Post-term or post-maturity pregnancy is defined as a pregnancy continuing beyond 42 completed weeks of gestation. The average incidence is about 10%. Post-term pregnancies carry increased risks for both mother and baby, including macrosomia, placental insufficiency, meconium aspiration syndrome, hypoglycemia, and stillbirth. Diagnosis involves confirming gestational age through menstrual history, clinical examination, and ultrasound. Management may involve induction of labor or continued monitoring, depending on fetal well-being as assessed by tests like biophysical profile and nonstress test. Preventing post-term pregnancy involves accurate dating using early ultrasound and monitoring pregnancies at risk of going past 42 weeks.

1. POST-TERM PREGNANCY
Joyce F. Mwatonoka, MD
April 2018

2. Outline
• Introduction
• Etiology
• Diagnosis
• Investigations
• Complications
• Management
• Sxs of post-maturity in a newborn
• Prevention

3. Introduction
• Post-maturity or post-term pregnancy is a
pregnancy continuing beyond two weeks of the
expected date of delivery (> 294 days/>42
completed weeks)
• Average incidence is about 3-12% (10%)
• Many suspected post-term pregnancies are
actually wrongly dated

4. Determining Gestational Age
• Naegele's rule
• Quickening (around 16 to 20 weeks GA)
• Uterine size, increases with GA
• Ultrasound examination in the first trimester
provides the most accurate dating
• Electronic Doppler ultrasound may detect
fetal heart tones as early as 10-11 weeks‘ GA

5. Etiology
• Wrong dates; inaccurate LMP (most common)
• Biological variability (hereditary/familial)
• Maternal factors: Primiparity, previous
prolonged pregnancy, sedentary habit and
obesity, elderly multiparae

6. Cont…
• Fetal factors: Congenital anomalies:
Anencephaly → abnormal fetal HPA axis and
adrenal hypoplasia → diminished fetal cortisol
response
• Placental factors: Sulphatase deficiency →
low estrogen
• Male baby

7. Diagnosis
1. Menstrual history; useful if the patient is
sure about her date
2. Clinical findings;
• Weight record: Regular periodic weight checking
reveals stationary or even falling weight
• Girth of the abdomen: It diminishes gradually
because of diminishing liquor
• History of false pain: that subsided

8. Cont…
• Obstetric palpation: The following findings, taken
together are helpful: height of the uterus, size of the
fetus and hardness of the skull bones. As the liquor
amnii diminishes, the uterus feels “full of fetus” a
feature usually ass/c post-maturity
• Internal examination: While a ripe cervix is usually
suggestive of fetal maturity, to find an unripe cervix
does not exclude maturity. Feeling of hard skull
bones either through the cervix or through the
fornix usually suggests maturity

9. Investigations
Aims are:
• To confirm the fetal maturity
• To detect placental insufficiency (fetal well
being)

10. Cont…
1. To confirm fetal maturity
• Sonography; Early ultrasound scan (in the 1st
trimester) can reduce the incidence of true post-
maturity
• Amniocentesis: The biochemical and
cytological parameters are helpful. However, this
invasive method has been mostly replaced by
sonography

11. Cont…
• Straight X-ray abdomen: Thickness and
density of the skull bone shadow, appearance
and density of the ossification centers in the
upper end of the tibia (38–40 weeks) and lower
end of the femur (36–37 weeks) are taken
together to assess the maturity
• Not commonly done

12. Cont…
2. Fetal well being assessment; done by twice
weekly,
• Nonstress test
• Biophysical profile (heart rate, movement,
breathing, and amnionic fluid volume)

13. Complications to the fetus/newborn
• Big baby (macrosomia)
• Placental insufficiency, which might cause;
-oligohydramnios (decreased amniotic fluid),
which might lead to IUGR, deformation and
increased risk of cord compression
-poor oxygen supply
• Meconium aspiration syndrome
• Hypoglycemia
• Antepartum stillbirth

14. Maternal complications
• An increase in severe perineal injury related to
macrosomia and operative delivery which is also
related to higher risk of hemorrhage,
endometritis and thromboembolic disease
• Increase in labour dystocia

15. Management
• Before formulating the plan of management one
should be sure of the Gastational Age
1. Induction of labour (likely)
2. Expectant management, with regular
ultrasound and biophysical profile

16. Symptoms of post-maturity in a
newborn
• Dry loose peeling skin
• Large amount of hair on the head
• Overgrown nails
• Green-yellowish/brownish coloring of the skin
from in-uteral passing of meconium
• More alert and wide-eyed

17. Prevention
• Women should keep truck of their menstral
cycles
• Ultrasonography in the 1st 12 weeks most
important

18. References;
• DC Dutta’s text book of Obstetrics
• Emedicine.medscape.com
• NMS Obstetrics and Gynaecology, 6th Edition
• Obstetrics by 10 Teachers 16th Edition