Antepartum haemorrhage - 1 File Download

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Antepartum haemorrhage

Introduction to antepartum haemorrhage

Placental abruption

Antepartum haemorrhage (APH) complicates between 2 and 5% of all pregnancies and is defined as bleeding of the genital tract, occurring from 24 weeks of geastation until birth.

The causes of APH vary and include, perhaps most significantly, placental abruption (30%), placenta praevia (20%), uterine rupture (rare) and vasa praevia (rare). Other causes include cervical lesions (such as polyps or ectropion), infection, trauma or malignancy.

APH poses a risk to both the fetus and the mother, and potential complications include maternal hypovolaemic shock (particularly since APH can predispose to postpartum haemorrhage), premature birth (up to 20% of very-preterm births are associated with APH), fetal hypoxia and intrauterine death. APH has been associated with an increased risk of cerebral palsy because it increases the risk of preterm delivery.

Diagnosis, medical and surgical management of the conditions that comprise APH are an integral part of an obstetrician's work. This tutorial will help you to competently treat this condition.

Learning objectives

When you have completed this tutorial you will be able to:

evaluate a woman with an APH be aware of the differential diagnoses diagnose a placenta praevia diagnose and manage placental abruption manage both conditions safely counsel a woman on the recurrence risks

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appreciate the importance of management protocols for the management of obstetric haemorrhage and be able to instigate guidelines including those for women who decline blood transfusion

appreciate the importance of regular skill drills for management of collapse, massive obstetric haemorrhage.

Last updated January 2015.

Preliminary assessments

Before starting the tutorial, complete the following preliminary assessments on antepartum haemorrhage:

The following assessment was written by MorvenLeggott and Charles Cox.

The following questions ask whether uterine rupture or dehiscence can be suggested by:

Answer whether the following statements are true or false.

Vaginal bleeding

True

False

Correct

The answer is true.

Poor progress

True

False

Correct

The answer is true.

Haematuria

True

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False

Correct

The answer is true.

Maternal tachycardia

True

False

Correct

The answer is true.

Abnormal CTG

True

False

Correct

The answer is true.

The following assessment was written by MorvenLeggott and Charles Cox.

The following questions are on cardiac arrest in a pregnant woman.


It is more likely to have a successful outcome than in the non-pregnant woman

True

False

Correct

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The answer is false.

It can be caused by hypovolaemia

True

False

Correct

The answer is true.

It contraindicates caesarean section

True

False

Correct


It requires external cardiac massage in the supine position

True

False

Correct


It requires endotracheal intubation

True

False

Correct

The answer is true.

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The following assessment was written by MorvenLeggott and Charles Cox


Hypovolaemia is better tolerated than anaemia

True

False

Correct


The aim is to restore the CVP measurement to 5 cm H2O

True

False

Correct

The answer is true.

Two units of fresh frozen plasma should be given for every five units of blood transfused

True

False

Correct

The answer is false. Four units should be given for every six units transfused.

A fall in blood pressure would indicate a blood loss of at least 1500 ml

True

False

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Correct

The answer is true.

Urine output is a useful measure of the effectiveness of resuscitation

True

False

Correct

The answer is true.


The incidence of antepartum haemorrhage is 1%

True

False

Correct

The answer is false. The incidence is 3% (50% are due to 'other' causes and 50% are praevia + abruptioplecenta).

The incidence of symptomatic placenta praevia is 4–8%

True

False

Correct

The answer is false. Symptomatic placenta praevia occurs in 0.4–0.8% of pregnancies.

Placenta praevia is a coincidental finding in 10% of abruption cases

True

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False

Correct

The answer is true. The usual presentation of placenta praevia as 'painless vaginal bleeding' may not be true in this situation.

Is defined as bleeding from the genital tract after 24 weeks of gestation

True

False

Correct

The answer is true. The definition can vary but 24 weeks of gestation is the time when fetal survival is reaching meaningful amounts.

In the presence of pain a vaginal examination is advisable to exclude labour

True

False

Correct

The answer is false. Digital vaginal examination is CONTRAINDICATED and should be deferred until an ultrasound has excluded placenta praevia.

The recurrence rate in subsequent pregnancies is 10–17% after one abruption and >20% after two abruptions

True

False

Correct

The answer is true. Recurrence is ten-times more likely if there is a previous history of abruption. There should be a high suspicion for recurrence, especially 2–3 weeks before the gestation age at which the previous abruption occurred.

Low socio-economic status is a risk factor

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True

False

Correct

The answer is false. Stillbirth and neonatal mortality rates for mothers resident in the most deprived areas were 1.8 and 2.2 times higher compared with rates in the least deprived areas. When specific causes are analysed it is difficult to prove an association between socio-economic status and abruptio placenta.

There is an established link between thrombophilia and abruption

True

False

Incorrect

The answer is true. The studies are contradictory but there is a link between abrupio and factor V Leiden mutation, prothrombin gene mutation, anticardiolipin antibodies and antithrombin deficiency.

Smoking has been identified as an independent risk factor

True

False

Correct

The answer is true. There is a consistent link between maternal smoking and abruptio placenta.

These questions asks whether the following are recognised risk factors for placental abruption.


Increased parity

True

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False

Correct

The answer is true. The RCOG Green-top Guideline on APH, as well as other works, have quoted multiparity as a risk factor for placenta praevia.

Increased age

True

False

Correct

The answer is true. Both placenta praevia and abruptio placenta are more common in women of increased age.

Trauma

True

False

Correct

The answer is true. Severe maternal injury is likely to lead to fetal loss in 40–50% of cases; however, 60–70% of fetal losses resulting from maternal trauma follow relatively minor maternal injuries.

Cocaine

True

False

Correct

The answer is true. Owing to its vasoactive properties, crack (heat-stable smokable cocaine) is associated with double the risk of abruption.

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Alcohol consumption

True

False

Correct

The answer is false. Under-reporting of alcohol consumption is widespread and, hence, the effect of alcohol consumption may not always be recognised. Some publications have documented alcohol as a risk factor but the link is not established.


In the management of placenta praevia, transvaginal scanning is of use in obese women as there are fewer problems with soundwave attenuation

True

False

Correct

The answer is true. The internal os of the cervix can be consistently seen to aid diagnosis of a placenta praevia.

In the management of placenta praevia, it is best to avoid transvaginal scanning as it can lead to haemorrhagic complications

True

False

Correct

The answer is false. Transvaginal scanning is indicated in suspected placenta praevia.

MRI is superior to transvaginal scanning in the diagnosis of placenta praevia

True

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False

Correct

The answer is false. It is more expensive and has no superior role.

In the management of placenta praevia, a full bladder is a pre-requisite for a transvaginal scanning

True

False

Correct

The answer is false. A full bladder is not necessary.

In the management of placenta praevia, 50% of patients diagnosed as having a low-lying placenta in the second trimester continue to have a placenta praevia at delivery

True

False

Correct

The answer is false. Approximately 2–3% of women with a placenta praevia at 20–25 weeks of gestation will still have a placenta praevia at delivery.

Initial assessment of an antepartum haemorrhage

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Placental abruption

An abruptio placenta is defined as the premature separation of the normally sited placenta from the uterus. The lower limit of gestational age to define placental abruption has changed over a period of years from 28 weeks down to as low as 20 weeks of gestation. Hall and Wagaarachchi (2002) defined placental abruption as occurring at any gestational age.

Placental abruption can lead to significant maternal and fetal morbidity and, ultimately, maternal and fetal death. Abruption is often an unanticipated emergency, although a small bleed can suddenly evolve into a major abruption. Therefore, vigilance is essential.

The incidence reported in various studies varies in different populations and different study designs.Ananth et al (1996) documented that the USA-based studies found a higher incidence in cohort (0.81%) and case–control studies (0.37%) than the non-USA studies (0.60% and 0.26%, respectively).

Pathophysiology of placental abruption

Abruptio placenta occurs when there is premature separation of a normally sited placenta.

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Bleeding begins in the decidua basalis and leads to the separation of the placenta from its attachment to the uterine wall. This separation can be partial and self-limiting or can extend until there is fetal hypoxia and, ultimately, demise.

Blood is seen at the vagina as it tracks down the uterus between the membranes and the uterine wall. If there is a large pressure generated in the uterus, the blood can extend into the myometrium (Couvelaire uterus), which becomes weakened and can rupture with increased intrauterine pressure during contractions. The uterus appears severely bruised and is infiltrated with blood. A Couvelaire uterus, named after Alexandre Couvelaire, may contract poorly and contribute to postpartum haemorrhage.

Abruptions are usually associated with pain and, in contrast with labour pain, the pain can be constant; however, labour may be concurrent. The pain is likely to be secondary to the infiltration of blood into the myometrium.

Clinical presentation of placental abruption

Placental abruption is a clinical diagnosis. Ultrasound is useful to confirm fetal viability/death and exclude a placenta praevia.

The features are:

vaginal bleeding (70–80%) – usually dark blood; however, the bleeding can be concealed, revealed or mixed

abdominal pain (50%) – usually constant, in contrast to uterine contractions uterine tenderness (70%) uterine contractions (35%) – abruptions can occur in labour or stimulate labour to begin fetal distress or intrauterine death evidence of a disseminated intravascular coagulopathy – non-clotting vaginal bleeding,

bleeding from drip sites and skin bruising.

Examination findings of placental abruption

The mother could present with features of shock depending upon the blood loss, or there may be hypertension.

Findings include:

uterine tenderness is found in 70% of cases abnormal uterine contractions (e.g. hypertonic, high frequency) are found in 35% of cases fetal distress is found in 60% of cases idiopathic premature labour is found in 25% of cases fetal death is found in 15% of cases.

Tikkanen et al found that vaginal bleeding (70%), abdominal pain (51%), bloody amniotic fluid (50%), and fetal heart rate abnormalities (69%) were the most common manifestations. Neither bleeding nor pain was present in 19% of cases.

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Placental abruption could be revealed or concealed:

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Classification of placental abruption

Classification is based on clinical presentations:

Class Presentation 0 Asymptomatic

Diagnosis is made retrospectively by finding an organised blood clot or a depressed area on a delivered placenta

1 Mild or no vaginal bleeding with no maternal or fetal compromise 2 Moderate or no vaginal bleeding with possible maternal evidence of blood loss

(tachycardia/mild hypotension but no clinical coagulopathy) Fetal distress

3 Severe or no vaginal bleeding with maternal compromise (tachycardia, hypotension and coagulopathy)

Tense, tender uterus, 'woody hard' Intrauterine fetal death

Note that all classes can be associated with the absence of vaginal bleeding. These cases are the 'concealed' abruptions and can present with a full-house of complications.

Classification of abruption varies. For example, Sher et al described three degrees of severity rather than four.

Laboratory studies

Full blood count

A full blood count (FBC) or Hemocue® are useful in evaluating the patient, but findings are not reliable enough to estimate blood loss. In acute haemorrhage, the fall in haemocrit value lags several hours behind the bleeding, and may decrease falsely with the administration of crystalloid fluids during resuscitation.

Blood group and crossmatch

The patient should be blood grouped and at least 4–6 units of blood crossmatched in the event she requires a transfusion. Urea, creatinine and electrolytes

Urea and creatinine levels can be altered as the hypovolemic condition brought on by a significant abruption affects renal function. The condition usually self-corrects without significant residual dysfunction if fluid resuscitation is timely and adequate.

Baseline levels of urea and creatinine are useful to monitor progression to renal failure. Electrolyte levels should be monitored, particularly potassium levels, which may rise with renal failure and blood transfusions.

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Liver function tests

Liver function tests should be done in case of underlying hypertensive disease and HELLP syndrome.

Laboratory studies part 2

Fibrinogen concentration

Pregnancy is associated with hyperfibrinogenemia; therefore, modestly depressed fibrinogen levels may represent significant coagulopathy. A fibrinogen level of less than 200 mg/dl (2 g/l) suggests that the patient has a severe abruption. Charbit et al reported a 100% positive predictive value for fibrinogen levels equal to or less than 200 mg/dl in detecting severe postpartum haemorrhage, whereas levels greater than or equal to 400 mg/dl have a 79% negative predictive value. Some form of DIC is present in up to 20% of patients with severe abruptions; however, mild abruption can occur without any blood test derangement.

Coagulation screen

Prothrombin time/activated partial thromboplastin time may be prolonged, also indicating coagulopathy.

Kleihauer–Betke test

This test is used to detect fetal red blood cells in the maternal circulation. If the abruption is significant, inadvertent transfusion of fetal blood into the maternal circulation may occur. In women who are Rhesus negative, this fetal-to-maternal transfusion may lead to isoimmunisation of the mother to Rh factor. Kleihauer–Betke test findings help determine the volume of fetal blood transfused into the maternal circulation and allow for the correct dose of Anti-D to be calculated.

Imaging studies

Ultrasonography helps determine the location of the placenta; location is used to exclude placenta praevia. However, ultrasonography is not a very sensitive method of diagnosing placental abruption. Sensitivity has been reported to be between 25 and 50%; however, the positive predictive value has been reported as 88% when ultrasound findings are present.

Retroplacentalhaematoma may be recognised in 2–25% of all abruptions. Tikkanen et al found that a retroplacental blood clot was seen by ultrasound in 15% of cases. Recognition of retroplacentalhaematoma depends on the degree of haematoma and on the operator's skill level. In the acute phase, a haemorrhage is generally hyperechoic – or even isoechoic – compared with the placenta. A haemorrhage does not become hypoechoic for almost 1 week.

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Aetiology

The true aetiology of placental abruption has not been elucidated; there is probably more than one cause. Recognised associated risk factors include:

previous abruption is the single most predictive factor for abruption (see section on Recurrence risk)

folic acid deficiency – there is no convincing evidence that deficiency is related to placental abruption. There is no evidence that folate supplements confer any improvement in abruption rates (see section on Folic acid deficiency)

owing to its vasoactive properties, the use of crack (the heat-stable smokable cocaine) increases the risk of placental abruption (see section on Cocaine).

cigarette smoking has been found to be associated with a 90% increase in the risk of placental abruption (see section on Cigarette smoking)

Hypertension/pre-eclampsia is regarded as a risk factor; however, there is no consensus on whether hypertension precedes abruption or vice versa. The relationship is stronger with chronic hypertension than pre-eclampsia.

underlying thrombophilia – factor V Leiden, prothrombin gene mutation (heterozygous and homozygous), protein C and S deficiency, antiphosholipid syndrome and homocysteinaemia have been associated with abruption. A meta-analysis by Roger et al found only a weak association between abruption and factor V Leiden and prothrombin 20210A gene mutations.

Aetiology - part 2

Other recognised associated risk factors include:

chorioamnionitis – well recognised link between chorioamnionitis and preterm labour (see section on Premature rupture of membranes [PROM])

multiple pregnancy – all complications are more common in multiple pregnancy, including abruption. The cause is unclear (see section on Multiple pregnancy)

fibroids – most pregnancies are unaffected by fibroids; however, large submucosal and retroplacental fibroids may be associated with complications (see section on Fibroids and placental abruption)

social deprivation trauma – the degree of trauma does not need to be major o road traffic accident o iatrogenic–external cephalic version, cordocentesis (see section on Trauma) raised alpha feto-protein in absence of fetal abnormality. Increased risk of FGR, preterm labour

and placental abruption fetal abnormality rapid uterine decompression (e.g. rupture of membranes with polyhydramnios) disturbed placentation – FGR, oligohydramnios, fetal abnormalities (aneuploidy), abnormal

umbilical artery Doppler

Folic acid deficiency

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In general, alcoholism is the most common cause of folic acid deficiency. However, in pregnancy, requirements may not be met if there is long-standing dietary deficiencies in addition to nausea and vomiting.

Placental abruption, as well as pre-eclampsia and recurrent pregnancy loss, are related to placental vascular bed defects. Dietary deficiencies of vitamin B12 and folate, in addition to other abnormalities within the methionine–homocysteine pathway, have been implicated in the development of this disease.

The link between folic acid deficiency and placental abruption was discovered by Hibbard in a series of studies. These studies found megaloblastic erythropoiesis in a high proportion of cases of placental abruption (Hibbard et al 1963).

The demands of pregnancy can exceed the available supplies of folic acid. This is less likely nowadays with the abundance of folic acid supplements, supplemented foods, such as breakfast cereals, and the increased awareness of women about its benefits.

Social deprivation and related poor dietary knowledge can lead to the inadequate consumption of fresh fruits and vegetables, which can in turn lead to folic acid deficiency. In addition, deficiencies due to intestinal malabsorption and medication in the form of folic acid antagonists may be a contributory factor in some cases (Hibbard et al 1963).

Recently, the Hordaland Homocysteine Study demonstrated that methylenetetrahydrofolate reductase (MTFR) is involved in the metabolism of folate and homocysteine; a polymorphism in the MTFR gene is associated with adverse outcome of pregnancy. The study concluded that this polymorphism was a risk factor for placental abruption. (Nurk et al 2004).

There is no convincing evidence to show that folic acid deficiency is related to placental abruption. It is difficult to demonstrate improvements in outcome by folate supplements from case–control studies because not all women would benefit, and a large sample size is needed for statistical purposes (Ray et al 1999).

Cocaine

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Cocaine has vasoactive properties. This leads to maternal hypertension and direct vasoconstriction to the uterine vessels, thereby compromising placental blood flow.

It has been suggested that vasoconstriction might cause disruption of placental adherence to the uterine wall, and thereby result in abruption. Vasoconstrictive effects within the fetus can result in cycles of relative ischaemia and rebound vasodilatation and hyperperfusion within various organs.

A previous review of cocaine use in pregnancy found an incidence of 2–15% of placental abruption in cocaine users. This is a higher rate than background (Fajemirokum-Odudeyi et al 2004).

In addition, a meta-analysis by Addis et al explored the effect of cocaine on malformations, low birthweight, prematurity, placental abruption, premature rupture of membranes and mean birthweight, length, and head circumference.

The study found that only placental abruption and premature rupture of membranes could be statistically related to cocaine – the other perinatal adverse effects were not statistically significant (Addis et al 2001).

The mechanism is attributed to vasoactive properties of cocaine, which leads to separation of the placenta by disrupting its adherence to the uterine wall (Pauli)

This aspect would be difficult to study experimentally, as is the situation with most aspects of illegal drug use in pregnancy.

Cigarette smoking

Smoking has been identified as an independent risk factor for abruption. A meta-analyses by Ananth et al showed that smoking is associated with a 90% increase in the risk of placental abruption. The risk of abruption was also directly proportional to the number of cigarettes smoked (Ananth et al 1999).

The same study also verified an increased risk of abruption in relation to both cigarette smoking and hypertensive disorders of pregnancy. It also showed that smoking by both partners multiplied the risk. Smoking cessation programmes may have the potential to modify the risk.

Smoking and hypertension are often linked outside of pregnancy, and reducing both of these factors is important in preventing placental abruption (Ananth et al 1999).

Hypertension/pre-eclampsia

Ananth reviewed 54 studies on abruptio placentae and found the pooled odds ratio for the association between abruption and chronic hypertension was 3.14 (95% CI: 2.59–3.80).

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Pre-eclampsia had an odds ratio of 1.81 (95% CI: 1.62–2.02) regarding its association with abruption placentae. Therefore, the relationship was stronger with chronic hypertension than pre-eclampsia (Ananth et al 1996). However, hypertensive discorders of pregnancy are associated with thrombophilias, which are also associated with abruption.

Thrombophilia

In a systematic review by Alfirevic et al, increased incidences of abruption was shown to be associated with the majority of thrombophilias, including factor V Leiden, prothrombin gene mutation, protein C and S deficiency, antiphospholipid syndromes and homocysteinaemia (Alfirevic et al 2002).

There is no proven intervention that can be introduced to prevent placental abruption in women with an underlying thrombophilia (Luesley et al 2004).

Premature rupture of membranes (PROM)

Holmgren et al showed an increased frequency of abruption in patients with early rupture of membranes. There was an inverse correlation to gestational length.

Clinicians should be aware of the significant association between preterm PROM and the risk of subsequent placental abruption: the earlier the mid-trimester PROM occurs, the higher the incidence of placental abruption. A study by Holmgren reported that the incidence of abruption was 13% when PROM occurred at 29–32 weeks, 44% when PROM occurred at 20–24 weeks and 50% when PROM occurred at less than 20 weeks (Holmgren et al 1997).

PROM for 24–47 hours and more than 48 hours increased the relative risk of abruption by 2.4 and 9.9, respectively. PROM associated with intrauterine infection and oligohyramnios increased the risk of abruption (relative risk: 9.0 and 7.2, respectively) compared with women with intact membranes (Ananth et al 2004).

Multiple pregnancy

Sudden decompression of the uterus after delivery of the first twin can lead to placental abruption.

Salihu et al conducted a retrospective cohort study to investigate the associations between plurality (number of fetuses per pregnancy), abruptio placenta and perinatal mortality.

Number studied PNMR (adjusted odds ratio)

Placental abruption (cases per 1000)

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Singletons 15 051 872 14.3 6.2

Twins 413 619 4.4 12.2

Triplets 22 585 3 15.6

The study concluded that as plurality increase from one to three, the risk of placental abruption rises, whereas the risk of abruption-associated perinatal mortality declines (Salihu et al 2005).

Fibroids and placental abruption

Fibroids (Wellcome Photo Library).

Ouyang et al pointed out that, owing to the lack of large clinical trials studying the effect of fibroids on pregnancy outcome, it is difficult to determine if fibroids are a factor in placental abruption.

Large submucosal and retroplacental fibroids may be associated with complications. Placental abruption can occur in association with retroplacental fibroids (Ouyang et al 2006).

Social deprivation and placental abruption

The CEMACH perinatal mortality report 2005 has shown that over one third of all stillbirths and neonatal deaths were born to mothers resident in the most deprived quintile (compared with the expected 20%). Stillbirth and neonatal mortality rates for mothers resident in the most deprived areas were 1.8- and 2.2-times higher compared with rates in the least deprived areas (CEMACH 2007).

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Burkett et al described an entire social milieu results in a pattern of risk not only related to polydrug use, but to increased risk of sexually transmitted disease, malnutrition, violence and lack of antenatal care, all of which can place the fetus at risk (Burkett et al 1994).

However, studies into stillbirth and infant mortality found that social deprivation is associated with death caused by specific conditions and infection. There was no evidence of significant association with death caused by placental abruption, intrapartum asphyxia and prematurity (Guildea et al 2001).

Trauma

Severe maternal injury is likely to lead to fetal loss in 40–50% of cases; however, severe maternal injuries are relatively rare. Approximately 60–70% of fetal losses resulting from maternal trauma follow relatively minor maternal injuries. Pregnant women involved in severe accidents were more likely to suffer abruptio placenta.

The RCOG has issued advice about three-point seat belts detailing that they should be worn above and below the bump, not over it. This followed recommendations of a survey and two CEMACH reports, which highlighted the need to inform pregnant women of the correct way to wear seat belts.

Unlike the first trimester, when minor trauma is not threatening to the pregnancy, the effect of even minor trauma can be significantin the second and third trimester. Preterm rupture of membranes, preterm labour, abruption, uterine rupture and direct fetal injury can occur.

Rapid acceleration, deceleration or a direct blow to the maternal abdomen can cause shearing of the placenta leading to partial or complete abruption (Reis et al 2000).

Recurrence risk

Recurrence is ten-times more likely if there is a previous history of abruption.

There should be a high suspicion for recurrence, especially 2–3 weeks before the gestation age at which the previous abruption occurred. After one episode of placental abruption there is at least a 10% chance that the condition will recur in a subsequent pregnancy.

After two episodes pregnancies affected by placental abruption, the chance of recurrence increases to between 19 and 25% (Tikkanen et al).

The RCOG Green-top guideline on antepartum haemorrhage highlighted ongoing research examining the possible role of low-molecular-weight heparin in preventing abruption in women with a history of previous abruption. In a pilot study, low-molecular-weight heparin use appeared to be associated with fewer placental vascular complications; however, at present, there is no convincing evidence for the use of low-dose aspirin with or without low-molecular-weight heparin in patients with thrombophilia as prophylaxis for abruption.

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Complications of placental abruption

Maternal complications

Placental abruption has been implicated in a range of maternal complications, including:

hypovolaemic shock secondary to haemorrhage coagulopathy/disseminated intravascular coagulation (DIC) acute renal failure Couvelaire uterus postpartum haemorrhage ischemic necrosis of distal organs (adrenal, pituitary) feto–maternal haemorrhage

Fetal complications

These include:

intrauterine death hypoxia and its sequelae anaemia fetal growth restriction (FGR) if chronic risks of preterm birth

Definition of placenta praevia

Placenta praevia is a placenta that is partially or wholly implanted into the lower uterine segment. Bleeding occurs when uterine contractions dilate the cervix, thereby applying the shearing forces to the placental attachment in the lower uterine segment.

Placenta praevia has been traditionally divided into four types. However, more recently it has been classifiedas either major or minor placenta praevia according to the clinical relevance.

type I (lateral placenta praevia) – the placenta just encroaches on the lower uterine segment type II (marginal placenta praevia) – the placenta reaches the margin of the cervical os type III (complete placenta praevia) – the placenta covers part of the os type IV (complete placenta praevia) – the placenta is centrally placed in the lower uterine

segment

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Enlarge

Note

This grading system is not a precise predictor of problems from a placenta praevia. A type I praevia may end in an emergency caesarean section at 30 weeks of gestation and a type IV praevia may not bleed at all and will just be diagnosed because of a high-presenting part. The grading system works better in a text book than it does in clinical practice.

The use of ultrasound allows clinicians to confirm a placenta that was in the lower uterus in the second trimester is not a placenta praevia at 28 weeks of gestation (i.e. as the lower segment develops, the low-lying placenta becomes normally sited). However, there may be over-diagnosis of asymptomatic placenta praevia before any bleeding has occurred.

Further reading

The WHO produced an article on interventions for suspected placenta praevia in The WHO Reproductive Health Library (RHL). The RHL takes the best available evidence from Cochrane systematic reviews and presents it as practical actions for clinicians to improve health outcomes, especially in developing countries.

Osman NB. Interventions for suspected placenta praevia: RHL commentary. Geneva: The WHO Reproductive Health Library; last updated 2007.

Incidence of placenta praevia

Symptomatic placenta praevia occurs in between 0.4 and 0.8% of pregnancies. Routine ultrasound examination in pregnancy has shown that low implantation of placenta occurs in 5–28% of pregnancies during the second trimester, but as the uterus grows, the placental site often migrates upwards so, by term, only 3% of pregnancies are praevia (not all are symptomatic).

Aetiology of placenta praevia

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Development of placenta is as a discoid condensation of trophoblast on the surface of chorion at approximately 8–10 weeks of gestation. The position of placental implantation will be decided by the site of implantation of the discoid trophoblast.

It is postulated that the placental migration, which is described previously, could be owing to the development of lower segment with the growing pregnancy. Alternatively, it could be due to differential development of the placenta, possibly affected by previous scarring or changes in vascularisation. Adherence to a lower segment may also explain the increased incidence of placenta praevia following a previous caesarean section.

The evidence that the umbilical cord in placenta praevia frequently has a marginal insertion could explain changes in vascularisation.

Maternal age and placenta praevia

The incidence of placenta praevia by maternal age is summarised in the following table (one study also shows a relationship with smoking status). Rates are per 100 pregnancies:

Studies <20 years 20–24 years

25–29 years

30–34 years

35+ years

Chamberlain 1978 0.1 0.3 0.5 0.6 1.5

Paintin 1962 0.1 0.2 0.4 0.7 0.7

Clark 1985 0.1 0.2 0.3 0.4 0.9

Naeye 1980 Non-smokers 0.2 0.4 0.4 0.8 0.8

Smokers 0.3 0.7 0.7 1.8 1.8

Adapted from Chamberlain G, editor. Turnbull’s Obstetrics. Churchill Livingstone: London; 1995. p 320.

Parity and placenta praevia

The incidence of placenta praevia by parity is summarised in the following table (one study also shows relationship with smoking status) where rates are per 100 pregnancies:

Studies Primi 2nd pregnancy 3–4th pregnancy

>5th pregnancy

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Naeye 1980 Non-smokers 1.5 1.8 1.7 1.8

Smokers 1.8 1.9 2.2 2.9

Paintin 1962 0.3 0.3 0.7 0.7

Clark 1985 0.1 0.2 0.4 0.6

Chamberlain 1978 1.1 1.4 1.4 1.7

Adapted from Chamberlain G, editor. Turnbull’s Obstetrics. Churchill Livingstone: London; 1995. p 320.

Cigarette smoking and placenta praevia

The table on the previous page explains a possible relationship between smoking and placenta praevia as reported by Naeye. Note that the relationship is not as strong as for abruption.

Previous caesarean section and placenta praevia

The risk of placenta praevia increases with previous caesarean section, which could be due to adhesion to the scar of a lower segment caesarean section. The incidence of placenta accreta is also increased.

In a study of 147 cases of major placenta praevia, McShane et al 1985 found 15% (22 patients) had a previous caesarean section. They also found that six out of 22 (27%) of the women in the group with previous caesarean scar had placenta accreta.

Clark et al studied the incidence of placenta praevia in 97 799 deliveries. They found that the incidence of placenta praevia in those who had not had a previous caesarean was 0.25%, in those with one caesarean scar it was 0.65%, and with three or more previous caesarean sections it was 2.2%.

Number of caesarean sections

Number of patients Instances of placenta praevia (%)

Instances of placenta accreta (%)

0 97 917 238 (0.26) 12 (5)

1 3820 25 (0.65) 6 (24)

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2 850 15 (1.8) 7 (47)

3 183 5 (3.0) 2 (40)

(The relationship between placenta praevia, placenta accreta and previous caesarean section, fromClark et al 1985)

Increased surface area and placenta praevia

It is presumed that conditions with increased surface area of placenta (twin pregnancies, succenturiate lobe and placenta menbranacea) will have placenta praevia, but there is little supporting evidence.

Previous uterine surgery

The tendency for adherence to a uterine scar explains the increased incidence of placenta praevia in cases of previous myomectomies, in which the endometrial cavity is opened. Damage to the endometrium also explains the increased incidence of placenta praevia after dilation and curettage.

A study by Rose and Chapman (1986) compared 80 women with placenta praevia with controls who were matched for age and parity. They confirmed that there was a significant relationship between placenta praevia and a history of dilation and curettage. There was a less significant relationship with surgical management of miscarriage (previously known as evacuation of retained products of conception) but no relationship to a previous induced abortion.

Symptoms of placenta praevia

The most prominent symptom is vaginal bleeding. The loss is:

painless (contrast with abruptio placenta) bright red (the blood is still oxygenated) can vary in amount from 'spotting' to torrential/life-threatening

The bleeding may be recurrent and could be provoked by sexual intercourse or the onset of labour.

The fetus is usually well and in good condition.

Signs of placenta praevia as a cause of APH

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If the mother is bleeding, she may be in shock, and the shock is usually proportional to the amount of blood lost vaginally. There is a negligible concealed component to the bleeding.

The presenting part is usually high and there may be a non-cephalic presentation. The uterus is usually soft and non-tender but there may be evidence of early labour with contractions and relaxation in between contractions.

Digital vaginal examination is contraindicated but a speculum examination is useful if there is only slight bleeding (to exclude local causes). If there is heavy bleeding, a speculum examination is unlikely to be of use.

Method of delivery

Placenta accreta should be suspected antenatally when there has been a previous caesarean section and placenta praevia or the placenta overlies the site of the scar with adequate preparations made for delivery.

Caesarean section is the usual method of delivery. With major placenta praevia, caesarean section is necessary, preferably electively.

With minor placenta praevia, vaginal birth may be attempted if the fetal head is below the leading edge of the placenta as the fetal head can access the birth canal without placental separation.

The grading system is not always a good predictor of which placenta praevia is going to bleed; however, as a minor placenta praevia can cause a severe bleed that terminates a trial of labour.

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Timing of delivery

The ultimate plan is to perform a caesarean section at 37 weeks of gestation. If the caesarean is delayed until 38 or 39 weeks of gestation there is a risk of the commencement of spontaneous labour and the provocation of a bleed that necessitates an emergency caesarean.

Indications for delivery before 37 weeks of gestation in a case of placenta praevia are:

1. Onset of labour (not able to be suppressed) 2. Fetal distress 3. Severe growth restriction 4. Intra-uterine death 5. Severe bleed (threatening maternal health)

In the case of suspected placenta accreta, delivery is advisable before 36–37 weeks of gestation.

How much bleeding is acceptable?

The volume of blood loss that is acceptable is dependent upon gestational age. At an early gestational age there must be severe blood loss, with or without fetal compromise, to warrant a severely premature caesarean.

At later gestational ages, lesser bleeding will lead to a caesarean as the prognosis for the fetus is increasingly good and there is the possibility that the blood loss escalating into a life-threatening bleed for the mother.

Probability of caesarean section at various gestational ages in a case

of bleeding palcentapraevia. Enlarge

Caesarean section for placenta praevia

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Caesarean section for placenta praevia carries a substantial risk of major obstetric haemorrhage and there should be a high index of suspicion for placenta accreta if the mother has had a previous caesarean section. Following the Confidential Enquiry in 2007, a care bundle with six elements of good care was developed, which provides guidance on pre-delivery planning. As highlighted in the RCOG Green-top guideline on placenta praevia, placenta praeviaaccreta and vasa praevia, these are:

consultant obstetrician should be present and scrubbed, and directly supervise delivery consultant anaesthetist planned and directly supervising anaesthetic at delivery blood and blood products should be readily available preoperative planning by the multidisciplinary team preoperative discussion and consent should include possible necessary interventions,

including hysterectomy, transfusion, the placenta remaining in utero, cell salvage, uterine artery embolisation and interventional radiology. Women who decline blood products should be transferred to a unit where cell salvage and interventional radiology are available

local availability of a level 2 critical care bed

The procedure typically involves:

1. Pfannenstiel incision 2. Lower segment procedure preferred 3. It is preferable to go around the placenta to deliver the baby (if the placenta has an anterior

component); however, it may be necessary to go through the placenta 4. Relatively rapid delivery of the baby and placenta then rapid repair of the uterus to minimise

blood loss 5. Some surgeons dilate the cervix digitally when the uterine wound is open to allow free

drainage of blood vaginally postoperatively 6. Intravenous oxytocin (5–10 units/hour) given with the third stage and continued for at least 6

hours postoperatively. However, as the placental bed is in the lower segment, this area may be less contractile and, therefore, oxytocics may be unsuccessful. Mattress sutures to the placental bed or balloon tamponade warrant consideration prior to closing the uterus.

7. Postoperatively, the patient should be closely observed for blood loss

Postoperative management following caesarean section for placenta praevia

Suggested post-operative management after a caesarean section for placenta praevia is as follows:

1. Observe overnight or for a minimum of 12 hours in the postoperative (recovery) area 2. Intravenous oxytocin infusion to run over a minimum of 4–6 hours postoperatively 3. Indwelling catheter left overnight 4. Analgesia as usual

Vasa praevia

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Vasa praevia is defined as fetal vessels crossing the internal cervical os. The major risk is to the fetus when the membranes rupture, whether spontaneously or artificially, as the fetal vessel presenting can tear, thereby causing a fresh antepartum haemorrhage. The blood lost is fetal and not maternal; therefore, a relatively small amount of bleeding can have a devastating effect. The fetal mortality rate for vasa praevia is approximately 60% (Fung et al 1998).

The incidence of vasa praevia has been reported to be between one per 2000 and one per 6000 pregnancies; however, the true incidence may be higher as this is not a condition routinely screened for antenatally.

There are two types of vasa praevia: type 1 occurs secondary to a velamentous cord insertion, whereas type 2 occurs when fetal vessels connect lobes of a placenta, for example when a succenturiate lobe is present.

Conditions with placental anomalies or more than a single discrete placenta increase the risk for vasa praevia, such as a bi-lobed placenta, multiple pregnancy and a low-lying placenta in the second trimester. Assisted conception has also been associated with a higher risk of vasa praevia, although the reason for this is unclear.

In the absence of vaginal bleeding, vasa praevia is occasionally detected intrapartum when vessels are felt in the membrane during vaginal examination. This may be confirmed using an amnioscope.

Although vasa praevia can be diagnosed on ultrasound scan using colour Doppler, routine screening is not recommended as the condition does not fit the World Health Organization’s proposed criteria for a screening programme.

Optimal management in the absence of bleeding is yet to be established. When vasa praevia is detected in the second trimester, there is some evidence that 15% of cases will resolve (Nelson et al 1990). If the vasa praevia persists in the third trimester, inpatient observation from between 28 and 32 weeks of gestation has been proposed (RCOG Green-top guideline 27), with antenatal corticosteroids and a plan for elective caesarean section, prior to the onset of labour, between 35 and 37 weeks of gestation.

If there is bleeding from a known or suspected vasa praevia, especially with suspected fetal compromise, delivery should be prompt and usually by caesarean section category 1.

Uterine rupture

Uterine rupture may present with vaginal bleeding. Uterine rupture is full-thickness loss of integrity of the uterine wall and visceral peritoneum. It differs from uterine scar dehiscence in that the former is associated with bleeding, fetal compromise and expulsion of uterine contents into the abdominal cavity. Uterine scar dehiscence does not involve the visceral peritoneum and the placenta and fetus remain in the uterine cavity.

Most cases of uterine rupture occur during labour following previous caesarean section or other uterine surgery, such as myomectomy. The incidence of symptomatic scar rupture is low,

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even in this high-risk group, at seven per 10 000 planned vaginal births following caesarean section (Landon et al 2004). The risk increases two- to three-fold with induction and augmentation of labour. It is rare with an unscarred uterus, affecting 0.5–2 per 10 000; these are usually multiparous patients in labour.

Signs of uterine rupture include bleeding, hypovolaemic shock, pain (often described as 'tearing'), loss of station of the presenting part, diminished uterine contractions and abnormalities of the fetal heart rate.

Several studies have found that CTG abnormalities are the commonest and earliest signs of uterine rupture in up to 87% patients whereas, in one study, abdominal pain was the first sign of uterine rupture in 5% of patients (Bujold et al 2002, Leung et al 1993, Rodriguez et al 1989).

In cases of suspected uterine rupture, stabilisation of the mother and emergency delivery are crucial. The Royal Australian and New Zealand College of Obstetricians and Gynaecologists highlight perinatal mortality rates of 0.4 per 1000 attributable to scar rupture during labour following previous caesarean section and maternal mortality has been reported as 17 per 100 000 (Landon et al 2004).

Final assessment

A 30-year-old G2 P1 woman with a placenta praevia attends the labour ward as an emergency admission from home. What is the best management in each scenario? Each answer can be used once, more than once or not at all.

A: Immediate lower segment caesarean section B: Immediate classical caesarean section C: Induction of labour D: Blood transfusion E: Observation F: Tocolytics + observation G: Blood transfusion + observation H: Elective lower segment caesarean section I: Elective classical caesarean section

The pregnancy is at 32 weeks of gestation and she has bled 500 ml.

Incorrect

The answer is immediate lower segment caesarean section. The prognosis for the baby is

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good. The blood loss has been marked and the potential for more blood loss is great/the increment in fetal survival rates is small and therefore a caesarean is indicated. The grade of praevia does not prognosticate the amount of bleeding; therefore, if it was grade 1 or grade 4 the amount of blood loss is sufficient to warrant a caesarean.

The pregnancy is at 37 weeks of gestation, there is a grade 3 praevia and the blood loss is 50 ml.

Incorrect

The answer is immediate lower segment caesarean section. The pregnancy has reached its logical conclusion and the blood loss may be followed by a greater loss, especially with uterine contractions associated.

There is a mild blood loss, the presentation is cephalic, the pregnancy is at 36 weeks of gestation and the praevia is a grade 1.

Incorrect

The answer is induction of labour. If the bleeding is not severe and the fetal condition is satisfactory, then a vaginal delivery is possible. Cephalic presentation and a previous vaginal delivery are favourable factors.

There is grade 4 praevia, no blood loss and a transverse lie at 38 weeks of gestation. The woman was admitted due to decreased fetal movements; the CTG is satisfactory.

Incorrect

The answer elective lower segment caesarean section. It may seem logical to perform a classical caesarean rather than a lower segment operation but the delivery of the placenta will be equally troublesome. The classical operation is more difficult and heals less well. If the fetus is lying in a dorso-inferior position the lower segment approach results in a more difficult delivery. Version to either a cephalic or a breech presentation will facilitate delivery with the lower segment operation.

There are no fetal movements and ultrasound confirms an intrauterine death. There is a grade 3 praevia at 34 weeks of gestation. There is no bleeding.

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Incorrect

The answer is elective lower segment caesarean section. There is no need to perform an emergency procedure and the support of senior colleagues is more easily available during the day. A caesarean is necessary even with an IUD as the intrapartum bleeding is still a severe problem.

The pregnancy is at 28 weeks of gestation. The woman has bled 500 ml but the loss seems to have reduced. The CTG is acceptable and the uterus is soft.

Incorrect

The answer is blood transfusion + observation. In order to justify a caesarean at 28 weeks of gestation the bleeding must be severe and continuing. If the loss has settled there may be valuable time gained with conservative management. An experienced obstetrician is required to manage this plan.

The pregnancy is at 30 weeks of gestation. There is an irritable uterus and a continuing trickle of blood lost vaginally. The fetus is healthy.

Incorrect

The answer is tocolytics + observation. Tocolytics are not contraindicated with a placenta praevia and may help gain valuable time. Extra time for steroid administration may be useful in the short term but once this episode is over days or weeks may be gained.

A primiparous woman is admitted at 32 weeks of gestation with a vaginal bleed of 150 ml. The uterus is tense, fetal parts are difficult to palpate and the symphysis-fundal height is 36 cm. Her BP is 100/60 and pulse is 110 bpm. What is the best management in each of the following circumstances? Each answer could be used once, more than once or not at all.

A: Request an ultrasound scan B: Oxytocin infusion C: Artificial rupture of membranes D: Artificial rupture of membranes + oxytocin infusion E: Immediate caesarean section F: Resuscitate mother and then perform a caesarean section

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G: Resuscitate mother and conservative management H: Observe I: Epidural anaesthesia J: Pethidine

The fetal heart is heard at 80 bpm.

Incorrect

The answer is immediate caesarean section. The clinical diagnosis is one of an abruption and immediate caesarean section is indicated if there is a live, viable baby. If the fetus is alive there is probably no clinically significant coagulopathy and, therefore, any delay for the results of coagulation tests is unnecessary.

The fetal heart cannot be heard with a Pinard's stethoscope or cardiotocograph machine.

Incorrect

The answer is request an ultrasound scan. If the fetal heart cannot be heard, an intrauterine death is suspected and the ultrasound scan will assist the diagnosis. Resuscitation should not be delayed to wait for the ultrasound.

There is a normal cardiotocograph tracing of the fetal heart.

Incorrect

The answer is immediate caesarean section. The survival of a baby born at 32 weeks of gestation is excellent (>95% will go home). The clinical diagnosis is an abruptio placenta and the correct mode of delivery is immediate caesarean as the abruption could progress rapidly and result in an intrauterine death. Mild cases of abruption can be treated conservatively but in the case presented there is vaginal bleeding and uterine pain and suspicion of a retroplacental clot.

Ultrasound scan confirms an intrauterine death.

Incorrect

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The answer is artificial rupture of membranes + oxytocin infusion. This is the only scenario in which labour is induced by artificial rupture of membranes with an intrauterine death. An oxytocin infusion adds to the success rate of the induction and speeds up the process.

If there is an intrauterine death and the labour process is ongoing.

Incorrect

The answer is pethidine. Epidural anaesthesia is contraindicated after an abruptio and pethidine will provide analgesia. Resuscitation of the mother is a matter of extreme urgency as the labour may progress very quickly and the third stage may take place with an active coagulopathy in a woman who has a depleted circulating volume.

If labour is established, the fetus is alive and the CTG is acceptable.

Incorrect

The answer is immediate caesarean section. The patient should be transferred to theatre for a caesarean section and the operation performed. If the woman delivers in theatre pre-operatively or on the way to the theatre the quickest method of delivery has been taken. If delivery has not occurred then the caesarean is performed.

If there is a transverse lie and an intrauterine death.

Incorrect

The answer is resuscitate mother and then perform a caesarean section. There is less urgency than the case where the baby is alive. A coagulopathy is common when the abruption has been severe enough to produce an intrauterine death and uncommon when the baby is alive. Thus the management is to resuscitate the mother (fluids and blood products) and then a caesarean section.

Regarding antepartum haemorrhage, answer whether the following statements are true or false.

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Placental abruption accounts for 10% of stillbirths

True

False

Correct

The answer is true. The unexplained group are the most common category, and antepartum haemorrhage is the second most common.

Placental abruption is associated with factor V Leiden deficiency

True

False

Incorrect

The answer is true. The odds ratio for being factor V Leiden positive is 6.7 (CI: 2–21.6).

Placental abruption is associated with pre-eclampsia in 80% of cases

True

False

Correct

The answer is false. Hypertensive disease is associated in approximately 50% of cases. It is not clear, however, whether the rise in blood pressure preceds or follows the abruption.

Postpartum haemorrhage is a known complicating factor

True

False

Correct

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The answer is true. Postpartum haemorrhage is a serious complicating factor and the reason for the correction of any coagulopathy before the third stage of labour.

Placental abruption can lead to renal failure from acute tubular necrosis

True

False

Correct

The answer is true. Acute tubular necrosis is usually reversible. The more serious acute cortical necrosis can also occur after an abruption.

Answer true or false whether the following were highlighted in the last Confidential Enquiry into Maternal Deaths 2003–2005 report.


The number of deaths from antepartum haemorrhage remained the same while those from postpartum haemorrhage reduced

True

False

Correct

The answer is false. All deaths (APH and PPH) were reduced.

All women with a previous caesarean section should have the placental site determined

True

False

Correct

The answer is true.

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Women with a high risk of bleeding should be delivered in centres with facilities of intensive care and blood transfusion

True

False

Correct

The answer is true. However, women at risk of haemorrhage are still delivering in isolated units.

Maternal mortality from obstetric haemorrhage is eight out of 100 000 maternities

True

False

Correct

The answer is false. The rate is 0.8 out of 100 000.

If a woman refuses blood or blood products despite her life being at risk, her wishes should be respected

True

False

Correct

The answer is true. Provided that she has capacity and is an adult, her wishes must be respected.

Regarding placenta praevia, answer whether the following statements are true or false.


A previous caesarean section is a risk factor for placenta praevia

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True

False

Correct

The answer is true. The risk approximately doubles with each additional previous caesarean.

A previous termination triples the risk of placenta praevia

True

False

Correct

The answer is false. A previous termination doubles the risk.

A maternal age of more than 40 years doubles the risk of placenta praevia

True

False

Correct

The answer is false. A maternal age of more than 40 increases the risk by nine-fold.

The incidence of placenta praevia is increased in twins

True

False

Correct

The answer is true. The large placenta from twins increases the risk.

The incidence of placenta praevia is increased in erythroblastosis

True

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False

Correct

The answer is true. Erythroblastosis increases the risk.



The incidence of symptomatic placenta praevia is 0.4–0.8%

True

False

Correct

The answer is true.

There is coincidental placental abruption in 10% of cases of placenta praevia

True

False

Correct

The answer is true. There is coincidental placental abruption in 10% of cases of placenta praevia.

In 50% of cases, labour occurs within a few days of a bleed from a placenta praevia

True

False

Correct

The answer is false. Labour occurs in 25% of cases.

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An oblique or transverse lie occurs in 30% of cases of placenta praevia

True

False

Correct

The answer is false. An oblique or transverse lie occurs in 15% of cases.

Fetal distress is a feature of placenta praevia

True

False

Correct

The answer is false. There are usually no signs of fetal distress unless there is a complication.



A transvaginal scan is contraindicated if placenta praevia is suspected

True

False

Correct

The answer is false. A TV scan is safe and more accurate than a transabdominal scan.

The growth of the fetus is not affected in cases of placenta praevia

True

False

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Correct

The answer is false. Growth restriction can develop with repeated haemorrhages.

Maternal mortality is 10%

True

False

Correct

The answer is false. Maternal mortality is less than 1%.

Perinatal mortality is 15%

True

False

Incorrect

The answer is false. Perinatal mortality is 2 to 3%.

It can be difficult to determine the lower edge of the placenta with a transvaginal scan compared with a transabdominal scan

True

False

Correct

The answer is false. With a transabdominal scan it can be difficult to determine the lower edge of a posterior placenta.


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A previous myomectomy predisposes to placenta praevia

True

False

Correct

The answer is true. Any uterine surgery (including curettage) increases the risk of placenta praevia.

The risk of fetal abnormalities is tripled

True

False

Correct

The answer is false. The risk of fetal abnormalities is doubled.

Fetal growth restriction occurs in 30% of cases

True

False

Correct

The answer is false. Fetal growth restriction occurs in 15% of cases.

The risk of placenta praevia is increased in women who smoke

True

False

Correct

The answer is true. There is a small but significant increased risk of placenta praevia in

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women who smoke.



A placenta praevia can be diagnosed in the second trimester

True

False

Correct

The answer is false. Although placenta praevia can lead to bleeding in the second trimester, it can only be diagnosed at 28 weeks of gestation when the lower uterine segment is formed.

At 16–18 weeks of gestation, up to 40% of placentas can be found to be low lying.

True

False

Incorrect

The answer is false. Only 5-28% of placentas can be low lying before 24 weeks.

Only 50% of low-lying placentas at 20 weeks of gestation remain low (praevia) at term

True

False

Correct

The answer is false. Up to 28% of pregnancies result in low-lying placentas at or before 24 weeks of gestation. This decreases to approximately 18% at 24 weeks and, by term, only 3% of pregnancies remain praevia.

However, some studies have reported that false-negative ultrasound scans for placenta praevia occur in 7% of cases.

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A transvaginal scan causes discomfort due to a full bladder

True

False

Correct

The answer is false. It is an advantage of transvaginal scanning that there is no discomfort as the bladder is empty.

MRI is superior to transvaginal scanning in the diagnosis of placenta praevia

True

False

Correct

The answer is false. MRI is more expensive and has no superior role.

Regarding an adherent placenta, answer whether the following statements are true or false.


A morbidly adherent placenta can occur following a previous manual removal of placenta

True

False

Correct

The answer is true.

The most common form of morbidly adherent placenta is a placenta percreta

True

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False

Correct

The answer is false. 80% of cases of morbidly adherent placenta are placenta accreta.

Colour flow Doppler is the investigation of choice for the diagnosis of a morbidly adherent placenta

True

False

Correct

The answer is true.

Adherence occurs because of abnormal development of the decidua basalis

True

False

Correct

The answer is true.

Uterine inversion can be a complicating factor for morbid adherence of the placenta

True

False

Correct

The answer is true. If manual removal of an adherent placenta is pursued, the uterus can be inverted.


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The RCOG recommends in-patient management of all women with placenta praevia

True

False

Correct


If a low-lying placenta is diagnosed in the second trimester, it is recommended that a repeat scan is performed at 34 weeks of gestation

True

False

Correct

The answer is false. According to the RCOG guideline for asymptomatic suspected minor praevia, imaging can be left until 36 weeks of gestation. For asymptomatic major praevia, imaging should be at 32 weeks of gestation to clarify diagnosis and allow for management of delivery.

Once placenta praevia is diagnosed, reassessment of fetal anatomy is necessary

True

False

Correct

The answer is true.

MRI should be routinely performed in all cases of placenta praevia to exclude accreta

True

False

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Correct


Low-molecular-weight heparin thromboprophylaxis should never be given with known placenta praevia

True

False

Correct


Regarding antepartum haemorrhage, answer whether the following statements are true or false.


If the lower edge of the placenta is within 2 cm at the internal os then it is safe to conduct a vaginal delivery

True

False

Correct


The optimum time for an elective lower-segment caesarean section is 37 weeks of gestation if no bleeding has occurred

True

False

Correct

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The answer is false. The optimum time is 38 weeks of gestation (RCOG guideline).

Cell salvage may be considered in cases at high risk of massive haemorrhage

True

False

Correct

The answer is true.

There is a place for cervical cerclage to reduce bleeding and prolong pregnancy

True

False

Correct

The answer is false. There is no evidence for cerclage outside of a clinical trial.

Prophylactic anticoagulation should be prescribed for prolonged in-patient care

True

False

Correct

The answer is false. This is reserved for those at high risk of thromboembolism. For low-risk cases, thromboembolic stockings will suffice.

Single best answer question

A 35-year-old para 2 has been admitted for post-dates induction of labour at 41+4 weeks of gestation. Her first baby was a normal vaginal delivery and her second baby was born by elective caesarean section for breech presentation.

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On the initial examination, the cervix was 2 cm dilated and the vertex at spines -1. On artificial rupture of the membranes the liquor was clear. An oxytocin infusion was commenced and an epidural sited. Three hours later she complains of sudden severe constant pain. The previously reassuring cardiotocograph shows atypical decelerations with slow recovery; then there is difficulty picking up the fetal heartbeat. On vaginal examination the cervix is 5 cm dilated and the liquor is blood stained with clots.

Grade 2 caesarean section.

Grade 1 caesarean section.

Perform fetal blood sampling.

Stop the oxytocin infusion and re-site the epidural.

Attach a fetal scalp electrode. Correct

The correct answer is grade 1 caesarean section due to possible uterine rupture and possible abruption.

A 39-year-old primigravida presents with a history of painless bleeding at 31+6 weeks of gestation. This is the first episode of bleeding during this pregnancy. At home, the blood soaked through her clothes and ran down her legs then filled two sanitary towels. By the time she arrives at the hospital, the bleeding seems to be settling. On the 20 week scan the placenta was covering the os and she has another ultrasound appointment in four days' time. Maternal observations are:

pulse of 106 beats per minute blood pressure 116/72 mmHg respiratory rate 18 breaths per minute temperature 36.7°C saturations 100% on room air

The cardiotocograph is reassuring. Which of the following would be most appropriate?

Tocolysis with atosiban.

Discharge and review in clinic after scheduled ultrasound scan in four days.

Cross match group-specific blood and admit for steroids.

Cervical cerclage.

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Admit for observation but delay steroids until immediately prior to elective caesarean section at 37 weeks of gestation.

Correct

The correct answer is cross match group-specific blood and admit for steroids.

You are asked to review a 28-year-old primiparous woman who was brought by ambulance with heavy vaginal bleeding at 32 weeks of gestation. Her total blood loss has been estimated to be around 2 litres. She appears to be bleeding from the venepuncture site. You suspect disseminated intravascular coagulation (DIC).

What treatment can be given empirically while awaiting the results of coagulation studies?

4 units of FFP and 10 units of cryoprecipitate

2 units of platelets and 8 units of cryoprecipitate

1 unit of platelets and 4 units of FFP

1 unit of platelets and 4 units of cryoprecipitate

1 unit of FFP and 4 units of cryoprecipitate Correct

The correct answer is 4 units of FFP and 10 units of cryoprecipitate. See Royal College of Obstetricians and Gynaecologists. Antepartum haemorrhage. Green-top Guideline 63. London; RCOG. 2011.

A 37-year-old primiparous woman presented with small antepartum haemorrhage and tightenings at 34+3 weeks of gestation. Ultrasound examination at 32 weeks of gestation showed a low-lying placenta. CTG trace is reassuring. Tocograph shows regular uterine activity.

What would be the next step in her management?

Ultrasound examination

Perform Kleihauer test

Offer corticosteroids

Internal examination

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Commence tocolysis Correct

The correct answer is offer corticosteroids. Clinicians should offer a single dose of antenatal steroids to women between 24+0 and 34+6 weeks of gestation. The Kleihauer test is not a sensitive test for diagnosing abruption. There is no place for the use of prophylactic tocolytics in women with placenta praevia. Vaginal and rectal examination should be avoided.

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