2. Introduction
Timely onset of delivery is an important
determinant of perinatal outcome.
Both preterm and postterm births associated
with higher rates of perinatal morbidity and
mortality
3. Definition:
The average duration of pregnancy is 280
days(40 wks), If this period is exceeded by
14 days(2 wks), it is referred to as post
term or prolonged pregnancy.
Postdate pregnancy implies pregnancy
lasting beyond the estimated date at 40
weeks.
4. Prevalence
5-10% of all
In US: 27% in the 40 th and 41 st week
5.5% at ≥42 weeks
Affected by:
* Routine early US assessment of GA (dated by first trimester
US the
prevalence of PTP is about 2% (versus 6-12% by LMP)
* Prevalence of primigravid women
* Prevalence of women with pregnancy complications
* Local practice patterns
5. Etiology and risk factors
Error in calculation of GA (the commonest)
No known etiology
Defects in fetal production of
hormones(anencephaly)
Placental sulfatase deficiency
Previous postterm pregnancy
* After one: two to three-fold
* After two: quadrupled
Nulliparity
6. Etiology and risk factors
Male fetus
Maternal obesity
Older/younger maternal age
Maternal or paternal personal history of
postterm birth
Maternal race (African-American, Latina, and
Asian are at lower risk than Caucasians)
7. Mortality and morbidity
Fetal and neonatal
Macrosomia (≥4500g) (2.5-10% versus 0.8-1% at term)
* Prolonged labor
* Cephalopelvic disproportion
* Shoulder dystocia
* Birth trauma (brachial plexus injuries and fractures)
Perinatal mortality
* twice the rate at term
* four-fold at 43w
Neonatal mortality
Placental insufficiency (hypoxia, asphyxia, meconium aspiration)
8. Mortality and morbidity
Fetal dysmaturity (postmaturity) syndrome
* Up to 20 percent
* Placental insufficiency, chronic intrauterine malnutrition
* Oligohydramnios
* Umbilical cord compression
* Meconium passage(physiological maturation or hypoxia)
* Long thin body, long nails, SGA
* Skin is dry, meconium stained,loose, prominent creases; lanugo
hair is
absent, scalp hair increased
* Short and long-term morbidities as IUGR
Intrauterine infection
9. Maternal risks:
Increased maternal
morbidity with large for
date or macrosomic
babies occurs because
of increased incidence
of:
• Dystocia
• Prolonged labour
• Shoulder dystocia
This results in an
increased risk of:
• pelvic floor trauma
• Instrumental deliveries
• Caesarian section (25%
incidence)
• Post partum
hemorrhage
• Endometritis
10. Management:
Two approaches
Both are associated with low complication rates in the low-
risk postterm gravida
favor induction of well-dated postterm pregnancies at or
shortly after 41 0/7ths weeks
expectant management with ongoing fetal assessment
11. Induction
Lower perinatal mortality and morbidity
No increase in or a reduction in cesarean
delivery
Patient satisfaction
cervical ripening agents even in women with
unfavorable cervices
membrane sweeping
12. Expectant management
Antepartum fetal demise increases with advancing GA
* 40-41 weeks: 0.86 to 1.08 per 1000
* 41-42 weeks: 1.2 to 1.27 per 1000
* 42-43 weeks: 1.3 to 1.9 per 1000
* >43 weeks: 1.58 to 6.3 per 1000
Neither method has been proven to be superior
NST with amniotic fluid volume assessment or by BPP
Induction for any usual obstetrical indications
amniotic fluid can become severely reduced within 24 to
48 hours
13. Antenatal Testing
Risk for uteroplacental insufficiency
Will not predict random unfortunate events
Based on physician experience
CST, NST, BPP, AFI
Three protocols in 583 women with completed 42w
gestation:
1-Weekly NST with CST for nonreactive NST
2-Twice weekly NST with BPP for nonreactive NST with induction
for a
4/10 BPP
3-Twice weekly NST with BPP for nonreactive NST and a weekly
determination of the amniotic fluid volume
Protocol 3 had the least perinatal morbidity and 1 highest morbidity
