Introduction

Most pregnant women spend their nine months waiting for this one day - their "expected date of delivery". It is a known fact that one of every 10 pregnancies goes beyond 40 weeks.

So when do you really have to worry? You don't really, because only really 2.5 - 7% of all pregnancies go beyond 42 weeks. Up to 42 weeks, it is relatively all right to wait without interfering unless complications arise.

The first step to take when the pregnancy advances beyond 40 weeks is to ascertain and reconfirm the actual gestational age using an ultrasonography. The second thing is to look out for the welfare of the baby. There are a few fixed changes that occur in an overdue pregnancy:

v A decrease in the amniotic fluid progressively
v An increase in the fetal weight
v The ageing of the placenta

Each of these can be monitored with a sonography. A decrease in the amniotic fluid is the consequence of decreased urine production by the fetus subsequent to a decrease in blood circulation through the fetal kidney (to compensate for the increased blood flow to the fetal brain).

An increase in the fetal weight poses difficulty in a normal vaginal delivery since the baby is large.

And lastly the aging of the placenta causes a decreased circulation to the baby- this probably is the most worrisome problem of an overdue pregnancy.

The overdue pregnancy leads to a few fetal problems as listed below:

v Fetal distress to due to a compression of the cord following a decrease in the fluid
v Fetal injuries during labour due to a large baby
v Post-maturity syndrome - these babies are typical in appearance. They are thin with dry, cracked, peeling, loose skin. They also have long nails and hair which may be stained yellow.

Necessary monitoring of an overdue baby

The reason for less worry today is the easy availability of tests for fetal monitoring.

1. Non stress test - twice or thrice a week
2. Fetal kick count charting - daily
3. Sonography for:
a. Baby weight
b. Amount of fluid
c. Placental age or grade
d. Biophysical profile for fetal activity and breathing movements
4. Doppler ultrasonography - for fetal circulation

All these tests have been discussed in detail under "Fetal Monitoring".

What can be done to induce labour?

Various measures can be taken depending on what you and your obstetrician think best.
a. Nipple stimulation - this can be done by the mother herself but can lead to hyperactivity of the uterus sometimes
b. Stripping the membranes - this involves manual separation of the membranes surrounding the fetus, from the lower part of the uterus. It must be performed by a doctor. It carries the risk of accidental rupture of the bag of waters.
c. Medical intervention with the help of prostaglandin E2 preparations like gels, tablets or vaginal suppositories. These may lead to hyperactivity of the uterus

All these methods of induction may be used even before 42 weeks if there are any signs of distress to the baby or in anticipation of a difficult labour. Each of these methods carries a risk of a higher chance of Caesarean deliveries due to non-progress of labour or fetal distress.

But don't worry, its not always that bad because only 4-8% of pregnancies actually end on their due date.