Polyhydramnios

I am 30 weeks pregnant and have been diagnosed with gestational diabetes. My obstetrician tells me that my tummy is big with excessive “amniotic fluid”. He says that I have “polyhydramnios”? What is Amniotic fluid? What does it do? What are the causes of polyhydramnios? Is it serious?

A. When you are pregnant, your baby grows in a bag filled with fluid. The sac is called amniotic sac and the fluid, amniotic fluid.

Initially, amniotic fluid is produced by the mother through the blood circulation. Soon, the baby starts to swallow the fluid and passes it out into the amniotic sac as urine. He or she will then swallow the fluid again and this process is repeated every few hours. Thus the amount of amniotic fluid is controlled by the baby to a large extent. If this regulatory system gets out of hand, excessive amount of fluid or too little fluid may result. The former condition is called polyhydramnios and the latter, oligohydramnios.

Normally, the amount of amniotic fluid increases as pregnancy progresses. It reaches its peak at around 34 to 36 weeks, measuring about 800ml. It then gradually decreases to about 600 mL at 40 weeks of gestation.

Amniotic fluid is important in maintaining a healthy environment for foetal development as it contains many nutrients, hormones and bacteria-fighting antibodies. Some of its important functions are as follows:

· It acts as a shock absorber protecting your baby from outside pressures.

· It helps your baby’s lungs and digestive system to develop. By breathing and swallowing the amniotic fluid, your baby will develop the muscles of these systems as it grows

· It insulates your baby, keeping it warm and maintaining a constant temperature

· The antibodies in the fluid will help protecting your baby against infection

· It prevents the umbilical cord from being compressed.

· It allows your baby to move freely in the amniotic sac, thus allowing the muscles and bones to develop properly

Polyhydramnios may be present in the following conditions:

1. Foetal factor:

· Digestive system: e.g. blockage of the food pipe (oesophageal atresia)

· Nervous system e.g. absence of a portion of the brain and skull, (anencephaly)

· Genetic abnormalities

· Infection

· Hydrops fetalis - a condition in which an abnormal level of water builds up inside many areas of the body

· Multiple pregnancies

2. Maternal factor

· Gestational diabetes.

I presume your baby has been examined by ultrasound and is presumably normal. The “Polyhydramnios” that you have is probably due to the gestational diabetes. Your obstetrician will monitor the levels of your blood sugar and the amniotic fluid closely. This is to prevent complications such as premature labour and premature rupture of membranes from happening.

Should you go into labour, you will be watched closely for cord prolapse (umbilical cord falls through the womb before delivery) and placental abruption (early placental separation). Both conditions may require immediate caesarean section.

After the baby is delivered, your obstetrician may give you medication to make the womb contract as your risk of postpartum haemorrhage is higher.

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Pregnancy