Shanthini and her husband have just come back from a visit to their obstetrician. Shanthini is 32 weeks pregnant and they have been told that the amniotic fluid around the baby is reduced. They are very anxious.

Salomi, on the other hand, has just the opposite problem. At 28 weeks, the fluid around the baby seems to be excessive. She has been asked to have a detailed ultrasound examination.

What is amniotic fluid?

Amniotic fluid is a clear liquid surrounding and protecting the foetus. The baby breathes this fluid into its lungs and also swallows it. It provides free space for the foetus to move around thus helping in the development of its limbs and muscles.

The foetus produces urine and the amniotic fluid consists mostly of that. As the foetus continues to grow, fluids from the baby’s lungs also contribute to the quantity of amniotic fluid.

The amount of amniotic fluid gradually increases until about 28-32 weeks of pregnancy. After that time, the level stays about the same until about 37-40 weeks, when your baby is considered full term. After that, the level begins to decrease.

When the amniotic fluid is low

A low amniotic fluid level is called oligohydramnios. This occurs in about 8 out of 100 of pregnancies. It is most common in the last trimester of pregnancy, but it can develop at any time in the pregnancy. Women whose pregnancies go past the due date have a greater chance of oligohydramnios. Oligohydramnios is diagnosed with ultrasound.

The causes of oligohydramnios

The most important causes of oligohydramnios in pregnancy are:

• Ruptured membranes (breaks or tears in the sac that holds the amniotic fluid)
• Birth defects involving the kidneys and urinary tract
• Maternal problems leading to oligohydramnios include high blood pressure, diabetes, an autoimmune condition called system lupus erythematosus (SLE), and placent al problems
• Certain painkillers like nimesulide can cause severe reduction of amniotic fluid. Check with your obstetrician before you take any medication.

The effects of oligohydramnios

Oligohydramnios may affect the foetus and the process of labour and delivery. It increases the risk of miscarriage, preterm birth and stillbirth. If it occurs early in pregnancy, too little amniotic fluid may result in abnormalities of the foetal lungs and limbs. When oligohydramnios occurs in the second half of pregnancy, it may be associated with poor foetal growth.

Near delivery, oligohydramnios can increase the risk of complications during labour and delivery. There is a greater chance of having a caesarean section when the amniotic fluid is decreased.

Treatment of oligohydramnios

If the ultrasound shows that the baby is healthy and if you are not leaking fluid, your obstetrician will recommend that you drink plenty of fluids. Though you need not be on complete bed rest, you should try to avoid strenuous work. Whenever you lie down, lying on your side will help increase placental circulation and circulation of blood to the baby.