Back to Basics!

The essence ofOBSTETRICSin two hours

Susan Aubin, MD, FRCSCAssistant ProfessorDepartment of Ob/GynThe Ottawa Hospital/University of Ottawa

Special Thanks to:Karine J. Lortie , MD, FRCSC

OVERVIEW

•Introduction•Early pregnancy•Antenatal care•Teratogens •Fetal growth and wellbeing•Medical complications•Breech•Multiple pregnancy •Labour

INTRODUCTION

RISK SPECTRUM IN PREGNANCY

LOW RISK (75%): normal obstetrics

MEDIUM RISK (20%): pre-post dates breech

twins maternal age, etc..

HIGH RISK (5%): genetic disease serious obstetric maternal complications

RISK IN PREGNANCY

Definition of Outcome Measures

1.Perinatal mortality rate• all stillbirths (intrauterine deaths) > 500 grams plus

all neonatal deaths per 1,000 total births2.Neonatal death

• death of a live-born infant less than • 7 days after birth (early) or less than 28 days (late)

3.Live birth• an infant weighing 500 grams or more exhibiting any

sign of life after full expulsion, whether or not the cord has been cut and whether or not the placenta is still in place

PERINATAL MORTALITY RATE

•ONTARIO: 5/1000

•Developing: 100/1000

PERINATAL MORTALITY

•Prematurity•Congenital anomaly•Sepsis•Abruption•Placental insuffienciency•Unexplained stillbirth•Birth asphyxia•Cord accident•Other ie. isoimmunization

MATERNAL MORTALITY RATE

•ONTARIO: 5/100 000

•Developing: 1000/100 000

MATERNAL MORTALITY

•Direct Deaths•Indirect deaths: < 42 days from delivery

Causes:•Hypertensive disorders•Pulmonary embolism•Anesthesia•Ectopic pregnancy•Amniotic fluid embolus•Hemorrhage•Sepsis

EARLY PREGNANCY

EARLY PREGNANCY

Dating:40 weeks from LMP280 days, Naegle’s rule (-3 months + 7 days)Affected by cycle lengthHegar’s sign: soft uterusChadwicks sign: blue cervix

8 days 8 weeks 16 weeks

5,000

Level

100,000

doubling time 2 days

Others use:Zone 2000-6000

•Mole•Ectopic•Ovarian cysts

Hormones

BhCG:A subunit similar to TSH, LH, FSHMeasurable 8 days post conceptionRole: stimulate CL progesterone

Other placental hormones

HPL = human placental lactogen (growth hormone)prolactinprogesteroneestrogen

ANTENATAL CARE

Maternal physiologyRBCplasma volume by 50%, GFR, CrCl (creatinine), glucosuriacardiac output (highest 1st hour after delivery)HR by 20%SVPlacental flow: 750ml/min at term

Antenatal careAntepartum history:age: >40 offer amniocentesisParity/gravidityMedical, surgical historyFamily, social historyMeds, allergies

Routine tests:CBC (Hg), Type and Screen, prenatal antibodiesVDRL, Rubella, Hep B, HIVUrine culturePap smear, + vag swabs, cervical culturesOffer IPSGBS swab at 35 weeks

Antenatal CareOther testing:Dating ultrasound, 18 weeks morphology ultrasoundHb electrophoresis (Thalassemia, sickle cell, etc.)Chicken pox, parvovirus, TSH28 weeks glucose screening testGenetic testing:CVSAmniocentesisScheduled visits:0-28 weeks: q4 weeks28-36 weeks: q2 weeks36+ weeks: q1 week

Scheduled visitsSFH (cm): (+ 2 # of weeks)Sensitivity of 60%12 weeks: symphysis pubis20 weeks: umbilicus36 weeks: siphisternumpresentationSymptoms, fetal movement+ urine dip: glucose, proteinBlood pressure, maternal weight

MATERNAL WEIGHT

wks gain

0 - 20 4 kg21 - 28 4 kg29 - 40 4 kgAverage 12 kg

•Weight Gain: •Underweight: 35-45 lbs (15-20 kg) •Normal BMI: 25-35 lbs (11-15 kg)•Overweight: less than 25 lbs (10 kg)

Genetic testing

IPS:First Trimester screening (10.6 – 13.6 weeks)

Nuchal translucency PAPP-A, (BhCG)

Second Trimester screening (15-16 weeks) BhCG, estriol, AFP, Inhibin A

87% detection rate, 2% false positive rate

MSS: (Quad test)15-19 weeksBhCG, estriol, AFP, Inhibin A77% detection rate, 5% false positive rate

IPS vs MSS Detection rate

NT

Suchet I, Tam W. The ultrasound of life. Interactive fetal ultrasound teaching program on DVD, 4th Edition, 2004.

Screening patterns

Down’s syndrome: low PAPP-A, AFP, estriol, high BhCG

Trisomy 18: low PAPP-A, AFP, BhCG, estriol, Inhibin A, high NT

Trisomy 13: high AFP, low BhCG/estriol

NTD: high AFP

Low estriol – associated with many congenital anomalies

Which of the following statements best describes the foramen ovale:

It shunts blood from right to left

It connects the pulmonary artery with the aorta

It shunts deoxygenated blood into the left atrium

It is an extra cardiac shunt

It is functional after birth

TERATOGENS

Risk Classification System for Drug Use in Pregnancy 

Category Description

A Taken by a large number of pregnant women. No increase in malformation. 

B Taken by only a limited number of pregnant women and women of childbearing age. No increase in malformation. Studies in animals wither show no increase or are inadequate. C Have caused or may be suspected of causing harmful effects on the human foetus or neonate without causing malformations. These effects may be reversible. 

D Have caused an increased incidence of human foetal malformations or irreversible damage. 

X Drugs that have such a high risk of causing permanent damage to the foetus that they should not be used in pregnancy. 

 

FETAL GROWTH AND WELL-BEING

Dating Scan

Gestational sac: 5wksFetal pole: 6wksFetal heart: 7 wksLimb buds: 8 wks crown rump length

Morphology scan

18- 20 weeksBPDHCACFemur length

Info from U/S

•Estimated fetal weight

•Twins discordance

•Behavioral states (BPP)

•Presentation

•Placenta (previa)

Anomalies: ultrasound 18 - 20 weeks

•Spina Bifida•Anencephaly•Cardiac•Renal•Diaphragmatic hernia•Limbs •Facial•Chromosomal

Late > 20 weeks

•Renal•Microcephaly•Hydrocephalus•Ureteral valves

Interventions•amniocentesis, l/s ratio (lung maturity)

•cvs

•cordocentesis, transfusion

•paracentesis

•Shunts: bladder, ascites, kidney, head

•Liver biopsy, skin

•Fetal reduction

DEFINITION OF I.U.G.R

•< than 2500 grams•< than 5th centile for GA•Approx. 4-7% of infants

BPD

AC

BPD

AC

CAUSES OF IUGR

•Maternal: Malnutrition Drugs Substance Abuse Diseases Infections

•Fetal: Chromosomal Abnormality Congenital Abnormality Multiple Gestation Congenital Infection

CAUSES OF IUGRPlacental:PerfusionAbnormalities:

Abnormal Cord Insertion Abruption Circumvallate placentation Placental Hemangioma Placental Infections Twin to Twin Transfusion

IMMEDIATE NEONATAL MORBIDITY IN IUGR

•Birth asphyxia•Meconium aspiration•Hypoglycemia•Hypocalcemia•Hypothermia•Polycythemia, hyperviscosity•Thrombocytopenia•Pulmonary hemorrhage•Malformations•Sepsis

CAUSES OF FETAL OVERGROWTH

•Maternal diabetes

•Maternal obesity

•Excessive maternal weight gain

EVALUATION OF WELL-BEING

FETAL ACTIVITY

•Kick counts:• “count to ten “ chart• towards term• 10 movements in 2 hours over 12 hours

BIOPHYSICAL PROFILE•Graded (0 or 2 pts; max 10)

• NST (normal)• Movement (2)• Tone (2)• AFI (amniotic fluid volume)• Breathing (30 seconds)

DOPPLER•What is it?

• Uteroplacental waveforms• Umbilical artery• Carotid artery• Descending aorta

CARDIOTOCOGRAPHYMaybe as good as BPP

1.Non-stress test: movement

uterine activity

2. Stress tests:Oxytocin infusion

nipple stimulation

Features of the normal CTG:• rate 110-160 bpm• BTB variation 5-15 bpm• Accelerations present (2)• No decelerations (early, variable, late)

Which fetus to assess?

Small for gestational age, postdatesMaternal hypertension, diabetesAntepartum hemorrhage Decreased FMThe “high risk” pregnancyEtc…

WHY FETAL ASSESSMENT?

1.To prevent damage (asphyxia)

2. To deter unnecessary intervention (prematurity,operative deliveries)

WHAT IS IT LOOKING FOR?

•Fetal hypoxia before asphyxia• Signs of placental failure:• Poor fetal growth• Decr. FM• Decr. AFI• Atypical, abnormal NST

•How to test?• Fetal scalp pH sampling• Normal >7.25• Borderline >7.21-7.25 (repeat sampling in ½ hour)• Abnormal <7.20 (deliver)

Criterias for asphyxia (hypoxic acidemia)

• umbilical cord arterial pH < 7.0

• base deficit > 16

• Apgar score 0-3 for >5 minutes

• neonatal neurologic sequelae (e.g. seizures, hypotonia, coma)

• evidence of multiorgan system dysfunction in the immediate

neonatal period

NORMAL TRACE

Early decels

Late Decels

Variable Decels

Reduced Variability

Tachycardia

MEDICAL COMPLICATIONS

NAUSEA AND VOMITING

•Morning sickness: 50%•Hyperemesis gravidarum: 1%

• Tx: • Diclectin (10 mg doxylamine succinate with vit B6)• Rest• Avoid triggers• Admit if severe (i.e. dehydration, electrolytes

imbalance)• TSH, LFT• IV• Dietitian consult• Psychology

DIABETES

Incidence: 1%GDM: 3-5%Screening: 50g GTT

If > 7.8 do 75 g 2 hr OGTT > 10.3 GDM

Risks factors:Previous stillbirthPrevious LGAFHxPersistent glycosuria

ORAL GLUCOSE TOLERANCE TEST (OGTT)

Criteria (ADA):•Fasting > 5.3•1 hour > 10.0•2 hour > 8.6

• 2 of the 3 values met or exceeded = GDM• 1 of the values failed = impaired glucose tolerance

Risks:•Anomalies•Infection•Pre-eclampsia•Macrosomia•Polyhydramnios•IUFD•shoulder dystocia

Rhesus isoimmunizationIncidence:

7% african-american13% caucasionIgG anti-D in Rh –ve sensitized women

Can cause:fetal anemiaheart failureHydrops fetalisBorn with jaundiceIn-Utero Dx: Amniocentesis, Cordo, DopplerProphylaxis: WinRho @ 28 wks + postpartum (newborn Rh status)

Antepartum hemorrage (>20 wks)

Causes:Placental abruption: concealed, revealed

Signs: vaginal bleeding, pain, fetal distress Causes:

PIH (DIC) Cocaine SLE Smoking Trauma Previous abruption

Abnormal placentation: previa, vasa previa Signs: painless vaginal bleeding

PPHCauses (4T):1.Uterine aTony:

• Twins• long labor• Etc…

2.Tissue (Retained products)• Infection

3.Trauma (tears)4.Thrombin:

• Congenital Disorders• APH

PPH Treatment

Conservative:Deliver the placentalBimanual compressionUterine packingIV, xmatch, blood bank (PRBC, FFP, …)

Medical:ErgotHemabateOxytocincytotec

PPH Treatment

Surgical: Repair the tear D&C (explore the uterus) Ligate internal iliacs UAE B-Lynch suture Backri balloon Hysterectomy

HYPERTENSION

HYPERTENSION IN PREGNANCY

•Leading cause of maternal death and perinatal mortality/morbidity

•BP monitoring is major activity of antenatal care

•Affects up to 10 % of all pregnancies

TERMINOLOGY

ABNORMAL VALUES? (depends on who…)•>140 / 90•DBP > 90 two readings•Systolic rise >30 or diastolic >15

PROTEINURIA>0.3 g/day (mild); >5 g/day (severe)

Gestational Hypertension with preeclampsia with comorbid conditions

Pre-existing Hypertensionwith preeclampsiawith comorbid conditions

Classification (it changes all the time…)

Eclampsia: Convulsion during pregnancy or within 7 days to 6 weeks of deliveryNot caused by epilepsy

Risk factorsPrimigravida or new partnerAge, raceLow social classFamilial trend ?single geneUnderlying hypertensive disorder 20 %diabetes 50 %Twins (mono) 30 %Hydatidiform molePrevious gestational hypertension 30 %

Severe:

• DBP> 110 with proteinuria (3-5g/d)• Symptoms:• Headache• Scotomas• Epigastric pain/RUQ• Vomiting• Hyperreflexia

Management

MILD: monitor, deliver near term

SEVERE: stabilize and deliver

MOTHER: • Labwork: CBC, LFT, uric acid, BUN, Cr,

Albumin/creatinine ratio or 24 hour urine total protein, LDH, INR/PTT

• Symptoms: IV, meds, ….

BABY :• BPP• Ultrasound: growth, doppler• NST• Celestone, …

ANTIHYPERTENSIVES

•Short or long-term:• Methyl dopa• Labetolol• Nifedipine

•Acute:• Labetolol• Nifedipine• Hydralazine

ANTICONVULSANTS•Prophylaxis and treatment:

• Magnesium sulphate

ECLAMPSIA

•Rx:• Control airway• Stop convulsion• reduce BP• MgSO4• Deliver (C. Section?)• watch post natally

BREECH

ETIOLOGY OF BREECH PRESENTATION

•prematurity•Fetal abnormality•Multiple pregnancy•polyhydramnios•Placenta previa•Uterine abnormality

TYPES OF BREECH PRESENTATION

Extended (frank)

Flexed (complete)

incomplete

footling

MANAGEMENT OF BREECH PRESENTATION

•If diagnosed >34 weeks, options:• External cephalic version• Trial of labor with vaginal delivery• caesarean

Criteria for TOL:•At 37 - 38 weeks:

• Estimated fetal weight 2.5-4 kg• Frank or complete breech presentation• clinical pelvimetry adequate• Fetal abnormality excluded• No serious medical or obstetric complications

TRANSVERSE LIE

•Incidence: 1:200 at term•Risk factors:

• Multigravidae• Placental previa• Fibroids• Polyhydramnios• Multiple pregnancy• Contracted pelvis• Fetal abnormality• Uterine abnormality

•Management:• Ultrasound• Cesarean if doesn’t turn

MULTIPLE PREGNANCY

Twins

•Incidence:• 1:80 (triplets 1:802)• 1:320 MZ twins worldwide

•superfecundation•superfetation

•Etiology: Population based Age Parity Previous binovular twins Heredity

TwinsDiagnosis:LGAu/s: lambda signIncreased AFP

Management:RestSerial u/sAssess presentation+ IOL @ 38 wks

Placentation

Dizygotic:Separate amnion and chorionSeparate placentas

Presentation:Vx/Vx: 45%Vx/BR: 25%Br/Vx: 10%Br/Br: 10%Etc…..

Placentation

DIZYGOTIC DAY

23 % 0 - 3 Totally separate

75 % 4 - 7 Separate fetuses & amnionsingle chorion with vascularconnections

1% 7 - 11 Monoamniotic & monochorionic

1% 11+ conjoined twins

Hazards of multiple pregnancy

•Increased risk pre-eclampsia (X3)•pressure symptoms•anemia

•Abortion (disappearing sac)•Prematurity (approx. 30% deliver < 37/40 )•Polyhydramnios•twin-twin transfusion•Placenta previa•APH/PPH•Malpresentation•cord entanglement

LABOR

What is Labor ?

(: work)

Regular painful uterine contractions

accompanied by progressive effacement and

dilatation of the cervix.

Timing of Labor

40 weeks

8% deliver on E.D.C.

7% premature <37 weeks

10% post-mature >42 weeks

Signs of Onset of Labour

•“Show”•Rupture of membranes•Contractions

Detection of ruptured membranes

•Nitrazine Test:• Alkaline pH of fluid turns blue

•Ferning:• High Na+ content causes “ferning” on air

dried slide

Ferning

Cord prolapseOnly with ruptured membranesIncidence: 1/300Risk factors:80% happen in multigravidaMalpresentation:

Transverse lie Breech High head

TwinsPrematurityOB interference: forcep, arm

Cord prolapse•Diagnosis:

• Ultrasound• Pelvic exam in labour (e.g. after ROM)• FHR abnormality

•Treatment:• Don’t panic• Push up presenting part• Sims position or knee/chest• Cesarean (forceps if fully)

Stages of Labor

1st stage: Onset to ‘full dilatationLatent and active

2nd stage: Full dilatation to delivery of baby

3rd stage: Delivery of placenta

4th stage: Placenta to 6 wks PP

Table 30-1. Characteristics of Labor Nulliparas and Multiparas*

Characteristic All patients Ideal Labor All patients Ideal laborNulliparas Multiparas

Duration of first stage(hr)Latent phase 6.4(±5.1) 6.1 (±4.0)4.8 (±4.9)4.5 (±4.2)Active phase 4.6(±3.6) 3.4(±1.5) 2.4(±2.2) 2.1 (±2.0)Total 11.0(±8.7) 9.5(±5.5) 7.2(±7.1) 6.6(±6.2)

Maximum rate of descent (cm/hr) 3.3(±2.3) 3.6(±1.9) 6.6(±4.0) 7.0(±3.2)Duration of secondstage (hr) 1.1(±0.8) 0.76(±0.5) 0.39(±0.3) 0.32(±0.3)

* All values given are ± SD.

(Data from Friedman EA: Labor: Clinical Evaluation and Management. 2nd ed. New York, Appleton-Century-Crofts, 1978).

Cesarean SectionIndications

Failure to progress (Dystocia)Repeat (Failed VBAC)Fetal DistressBreech PresentationPlacenta PreviaCord prolapseAbruptionDiabetesFetal Reasons (e.g. prevent infection)Social...

Premature labor

Incidence: 7% <37 wksMajor cause of perinatal morbidityOverall recurrence risk of 30%Risk factors:Previous PTDSmokingLow incomeCervical surgeryUterine anomalyMultiple pregnancy

Premature labor

Treatment:RestSteroids (for fetal lung maturity)Tocolytics?PPROM:

Mercer protocol (IV/PO ampicillin(amoxil)/erythromycin)

Prevention:Ultrasound cervical length?Fetal fibronectin (predictor?)

Amniotic Fluid•Mainly fetal urine•Some from extraplacental membranes

• 12 wks: 50 mls• 24 wks: 500 mls• 36 wks: 1,000 mls

•Oligohydramnios:• Reduced AFI on u/s: <5cm • SFH: small for dates; baby easy to feel• Causes: • Placental insufficiency• Urinary tract dysplasia• Diagnosis:• Ultrasound• Treatment:• Intensive monitoring• Early delivery

Polyhydramnios•Definition:

• An excess of liquor to such a degree that it is likely to influence the course or management of pregnancy.

• >20 cm

•Diagnosis:• SFH increased: large for dates• Tense and uncomfortable• Fluid thrill• Difficult to feel fetus

Polyhydramnios: EtiologyMaternal:

MultipDiabetesGHTNInfection: toxoplasmosis, CMVFetal:MacrosomiaAnencephaly, hydrocephalyGut atresiaMultiple pregnancyCAN’T SWALLOW (diaphragmatic hernia, mediastinal tumor)HYDROPS FETALIS (Rh incompatibility, infection, heart disease, thalassemia major, etc.)

Dystocia

Definition:Abnormal progression of labour in the ACTIVE Phase

Cervical dilatation of <0.5 cm/hr over a 4 hr period

arrest of progress in the ACTIVE phase either in the first or second stage of labour

Failure of descent of presenting partFriedman’s curve

CAUSES OF DYSTOCIA

Power Uncoordinated uterine action Dysfunctional Labour

Passenger Cephalo-pelvic disproportionRelative disproportionMassive baby! (macrosomia)

Passages Diameters (pelvic anatomy)

Dystocia

Risk Factors:ageParityInfectionEpiduralPosition in laborInductionMacrosomiacervix

Initial measure to treat dystocia

Comfortwellbeinghydration

B. AmniotomyC. Oxytocin if A+B failD. Wait long enough to see a response

A. Attention to:

Oxytocin usage

•Dosage:• Depends on your hospital protocol• Initial dose: 1 to 2 mu/min• Rate increased by 1 to 2 mu/min every 30 min

until contractions are considered adequateand cervical dilatation achieved

• Clinical response usually seen at dose levels of 8-10 mu/min

Reduction of risk of dystocia

Avoid induction for large fetal weightAvoid oxytocin use with unfavourable cervixAvoid admission to Labour and Delivery at <4cm dilatation“Management” of epidural at full dilatationAvoid immediate pushing after full dilatation

Supportive strategies

Cervical evaluation for ripening prior to booking inductionObstetrical triageContinuous professional support in active labourMobilization of women in active labourMinimization of motor blockage with epiduralUse of amniotomy and oxytocin prior to C/S for dystocia

Cesarean section for dystocia

Timing of procedure RateLatent phase 41%Active phase 38%Second stage 21%

Source: Stewart CMAJ 1990:142; 459-463

The perinatal mortality rate is defined as:

a)The number of neonatal deaths that occur per 1000 live births

b)The number of stillbirths that occur per 1000 births

c)The number of fetal deaths within the first week after birth

d)The number of stillbirths and neonatal deaths in the first week of life per 1000 live births

All of the following factors are associated with an increased risk of perinatal morbidity except:

a) low socioeconomic status

b) low maternal age

c) heavy cigarette smoking

d) alcohol abuse

e) exercise

Appropriate management for slow labour (dystocia) associated with an occiput posterior presentation during the first ACTIVE stage of labour would include:

a) immediate cesarean section

b) forceps

c) augmentation with oxytocin

d) external cephalic version

e) fetal blood sampling

Appropriate screening tests in an early, uncomplicated pregnancy include all of the following except:

a) repeat BhCGb) hemoglobinc) syphilis serologyd) Cervical cytologye) Blood type and Rh factor

Characteristics or associated findings with late decelerations include all of the following except:

a)They may be seen in patients with pre-eclampsia

b)They may be associated with respiratory alkalosis

c)They are associated with a decreased uteroplacental blood flow

d)They often are accompanied by decreased PO2

e)They usually are accompanied by an increased PCO2

A complete breech presentation is best described by which of the following statements:

The legs and thighs of the fetus are flexed.

The legs are extended and the thighs are flexed.

The arms, legs, and thighs are completely flexed.

The legs and thighs are extended.

None of the above