postterm pregnancy

Definition

Post Maturity: Specific syndrome of infant associated with postterm pregnancy.

Postterm pregnancy : is 42 completed weeks (294 days) or more from the first day of the last menstrual period. It is important to emphasize the phrase "42 completed weeks”. (American College of Obstetricians and Gynecologists (2004)

Estimated Gestational Age Using Menstrual Dates

Thus, there are two categories of pregnancies that reach 42 completed weeks: (1) those truly 40 weeks past conception, and (2) those of less advanced gestation but with inaccurately estimated gestational age.

menstrual dates are frequently inaccurate in predicting postterm pregnancy.

Sonographic at 16 to 18 weeks, or both of gestational age during pregnancy has been used to add precision

inciden

By Last menstrual Periode :

7.5 %

By USG : 2.6 %

BY LMP + USG : 1.1 %

The tendency for some mothers to have repeated postterm births Previous 1 postterm : 27 %Previous 2 postterm : 39 %

Risk factor• The most frequent cause is an error in dating

( the first day of last period)• Primiparity and prior postterm pregnancy are

the most common identifiable risk factors• Decreased fetal estrogen production Placental sulfatase deficiency Anencephaly (Deficiency of ACTH in fetus) Fetal adrenal hypoplasia• Male sex also has been associated. • Genetic predisposition may play a role .

patofisiology

• The influence of progresteron

• Theory of oxitocin

• Theory of kortisol

• Uterus nerve

• herediter

a decrease in the hormone progresterone in pregnancy is believed to change event that are more important in stimulating the endocrine processes on childbrith and increase biomolekuler the sensitivity uterus of oxytocin, so some authors oxytocin suspect that the occurence of postterm pregnancy is the on going influence of progresteron

use of oxitocin for induction of labor in postterm pregnancy it’s believed that oxytocin physiologically hold an important role in childbirth raises and the release of oxytocin (from neurohipofisis) pregnant women who are less advanced in their pregnancy is suspected as one or the factor of postterm pregnancy causes

In this theory proposed that the giver to sign start of delivery is due to an increased in fetal plasma cortisol levels. Fetal cortisol affect the plasenta so that production decreased secretion of progesterone and estrogen, later enlarged to the increasing production of prostaglandins. Fetal conginetal defect such as the anensephalus, fetuses, adrenal hipoplasia, and absence of pituitary gland in fetuses will cause fetal cortisol produced not properly so that pregnancy can take place though the month.

Pressure on the ganglion of cervical plexus of the contraction of the uterus frankenhauser will stir. In circumstances where there is no pressure on the plexus, the short cord and the bottom is still high as cause of the occurence of all of these suspested of postterm pregnancymother experience of pregnancy gave birth to

daughter postterm moment, then likely her daughter will experience pregnancy postterm

Risks factor

fetus• Doubling of perinatal

mortality• Asphyxia, meconium

aspiration,intrauterine sepsis• Fetal macrosomia• Fetal dysmaturity syndrome• oligohidramnion• Fetal trauma brachial plexus injuries,

clavicle fracture

mother• Increased risk of

labor abnormalities• Anxiety• Traumatic vaginal delivery-

shoulder dystocia• Increased CS rate• PPH risk

Perinatal Mortality

• Incidence of fetal mortality for all groups is as follows:

– 40-41 weeks’ gestation : 1.1%– 43 weeks’ gestation : 2.2%– 44 weeks’ gestation : 6.6%– Fetuses born postterm also are at increased risk of :

Sudden infant death syndrome (death within the first year of life).

– Some of these deaths clearly result from peripartum complications (such as meconium aspiration syndrome), but most have no known cause.

Placental Dysfunction

• placental apoptosis—programmed cell death—was significantly increased at 41 to 42 completed weeks compared with that at 36 to 39 weeks. The clinical significance of such apoptosis is currently unclear.

• cord blood erythropoietin. stimulator of erythropoietin is decreased partial oxygen pressure. cord blood erythropoietin levels were significantly increased in pregnancies reaching 41 weeks or more.

Hypoxia, meconium

• In some cases, the risks appear to be due to uteroplacental insufficiency, resulting in fetal hypoxia , meconium aspiration, growth restriction, and oligohydramnios .

• Fetal distress and meconium release were twice as common (at or after 42 weeks) than at term.

• There was an eight-fold increase in meconium aspiration

oligohidramnion

• The volume of amnionic fluid normally continues to decrease after

38 weeks and may become problematic

• diagnosis :

No vertical pocket > 2 cm or maximum-vertical amnionic fluid

pocket measured 1 cm or less at 42 weeks

Amniotic fluid index (AFI) 5 cm or less .

• It is considered an indication for delivery

• Moreover, meconium release into an already reduced amnionic fluid volume causes thick, viscous meconium that may cause meconium aspiration syndrome

macrosomia

In other cases, continued growth of the fetus leads

to macrosomia, increasing the risk of

labor abnormalities, shoulder dystocia with

resultant risks of orthopedic or neurologic injury.

Macrosomia is far more common in postterm than

term pregnancies (45%)

10%-IU malnutrition

Postmaturity syndrome

• Features include wrinkled, patchy, peeling skin; a long, thin body suggesting wasting; and advanced maturity because the infant is open-eyed, unusually alert, and appears old and worried.

• Skin wrinkling can be particularly prominent on the palms and soles.

• The nails are typically long.

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How can you assess the post-term fetus antenatally?

A. FHR testing:

• NST (non-stress test):– Non-invasive test of fetal activity that correlates with

fetal well-being.

– Fetal heart rate accelerations are observed during fetal movement.

– External monitor is used to record FHR & mother precipitates by indicating fetal movement.

– NST can be reactive or non-reactive.

• Contraction Stress test: not used anymore.

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B. Biophysical profile (BPP):

• Composite of tests designed to identify a compromised fetus during antepartum period.

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Biophysical Profile (BPP)

Parameter Normal (2 points) Abnormal

(0 point)

Amniotic Fluid Volume (AFV)*

Fluid pockets of 2 cm in 2 axes.

Oligohydramnios

NST Reactive. Non-reactive

Breathing At least 1 episode of breathing lasting at least 30 sec.

No breathing

Limb movement 3 discrete movements. ≤ 2

Fetal tone At least 1 episode of limb extension followed by flexion.

No movement

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Score Interpretation Mx

8-10 Normal Repeat BPP as clinically indicated

6 Suspect chronic hypoxia

Repeat BPP in 4-6 hours

0-4 Strongly suspect chronic asphyxia

Deliver fetus if mature

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How can you manage suspected post-dates pregnancy?

1. Determine gestational age dating.

2. Establish how favorable cervix is (dilated, effaced, soft).

3. Assess fetal well-being [e.g. with NSTs & amniotic fluid indices (AFIs)].

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4. Use the following triage method:– Dates are certain & cervix is favorable. Neither the

mother nor the fetus benefits from waiting induce labor promptly with IV oxytocin & rupture of membranes.

– Dates are certain but cervix is unfavorable. Risk of failed induction is high. If fetal macrosomia is suspected SC. Alternatively, if the estimated fetal weight (EFW) is normal, manage expectantly with twice-weekly NSTs & AFIs.

– Dates are unsure. Because it’s not known if the patient is post-dates, delivery is not indicated. Manage expectantly with twice-weekly NSTs & AFIs awaiting spontaneous labor.

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5. Intrapartum:• Meconium staining:• Prior to delivery Amnio-infusions• After delivery of fetal head suctioning

meconium from nose & pharynx to prevent aspiration.

• After delivery of entire fetus, but before the first neonatal breath aspirate neonatal tracheal meconium using laryngoscope.

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• When macrosomia is suspected, should be performed to estimate fetal weight. Clinician should always be prepared to deal with a potential shoulder dystocia.

• Intrapartum asphyxia: Careful monitoring should be instituted when this is suspected.

When to Induce: Indications

Urgent / High PriorityNon-reassuring statusChorioamnionitis PPROM at 35wksSevere Pre-eclampsiaIUGR below 3%Anyone >42wks

Medium PriorityFetal malformation Mild pre-eclampsiaIUGR below 10%AFI 5-8Multiple gestation >38wks

• Labour induction at 41 weeks gestation is recommended over expectant management in women with postterm pregnancy to reduce the rate of cesarean delivery & perinatal mortality .

• In the end of postterm pregnancy with oxytocin induction, patient must filled several terms, which is aterm pregnancy, normal pelvic size, no disproportion cephalopelvic, head presentation, cervix is ready (portio feels soft, flatening, and start to open). Beside that, size of pelvic should be done before.

Contraindications:

• Placenta Previa and Vasa • Fetal position: breech, transverse, mentum• Polyhydramnios • Abnormal FHTs

Is the cervix favorable?Bishop < 6 = Unfavorable soMechanical Cervial Ripening Stripping of membranesLaminariaTranscervial Foley Catheter- speculum exam, ring

forcepts, 30cc foley , sterile saline Monitor FHT for reactivity, insert foley through cervial

internal ostiumProstaglandin

Misoprostol (Cytotec)Gel Capsules 25mcg pv (4x every 6 hours)

Oxytocin Induction

Bishop score > or equal to 6 = Favorable “Low Dose Active Management”Start oxytocin at 8 milliunits/min and go up 4

miliunits/min by 15 mins (max 40 miliunits/min)

Bishop score > 5 inductionbisshop < 5 Cervial Ripening

Identification of patients that need delivery

Ripe cervixOligohydramnios

MacrosomiaAbnormal NST/BPP/CST

Meconium stained liquor

Unripe cxNormal fluid

Normal NST/CSTNormal fetal size

Cervical assessment,NST,AFIWeekly at 40 & 41 wksTwice wkly thereafter

Ripe cxOligo

Abn NST42 WKS

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