When excessive amniotic fluid surrounds the fetus in the womb, women experience a condition called polyhydramnios. The amount of amniotic fluid in the womb increases gradually up to 1 quart by week 36 of pregnancy. The amount of fluid appears to decline after this period.
What is polyhydramnios?
Polyhydramnios, or hydramnios, is an excessive amount of amniotic fluid around the fetus in the uterus. The amniotic fluid is produced by the kidneys of the fetus, which flows into the womb through the fetus’s urine.
The fetus then gulps the fluid and reabsorbs it while respiring. This act of swallowing helps balance the amount of amniotic fluid in the womb. This process maintains a vibrant balance between the production and absorption of amniotic fluid. Complications can arise for mother and fetus when this balance is disturbed.
Most women with polyhydramnios often feel no signs or symptoms, however, when symptoms do occur, they can include premature contractions, difficulty breathing, or abdominal pain.
When the uterus is larger than expected for the age of the fetus, this could mean presence of excessive amniotic fluid. A woman can usually tell that her belly is growing too quickly.
Polyhydramnios can develop for several reasons, such as:
- the fetus having difficulty swallowing the amniotic fluid
- multiple pregnancies
- congenital malformations
- maternal diabetes, which doctors also refer to as gestational diabetes
- the fetus producing an increased amount of urine
- problems affecting the fetus’s genetic makeup, lungs, or nervous system
- infection in the fetus
- anemia, or a lack of red blood cells, in the fetus
Risks and complications for both woman and fetus
Possible complications for the woman include:
- premature contractions leading to preterm delivery
- the water breaking too early
- longer labor
- premature separation of the placenta from the wall of the womb
- difficulty breathing
- uncontrolled bleeding after labor
Possible complications for the baby include:
- congenital abnormalities
- abnormal size or positioning
- dangerous positioning of the umbilical cord
- death in severe cases
Doctors diagnose polyhydramnios before the baby is born. Doctors will perform an ultrasound exam using waves to measure the amount of amniotic fluid in the womb and look for any fetal abnormalities.
Doctors can also check for conditions that can cause polyhydramnios by performing blood tests and a procedure called amniocentesis (doctor collects a sample of amniotic fluid from the womb and sends it to a laboratory for genetic investigation).
Doctors try to reduce the amount of amniotic fluid in the womb to treat polyhydramnios. This can lengthen the pregnancy and improve the woman’s well-being. A doctor may use one of the following methods to reduce the volume of fluid:
- Reduction amniocentesis: Doctors draw fluid from the womb.
- Medications. These could include prostaglandin synthetase inhibitors or sulindac, which is a nonsteroidal anti-inflammatory drug.