Definition

Polyhydramnios is too much fluid in the amniotic sac. The amniotic sac is the “water bag” inside the womb. It protects your baby. Usually, there is about 1 liter of fluid by 36 weeks of pregnancy. Polyhydramnios is an amniotic fluid index (AFI) of greater than 25 cm. About 2% of pregnant women have more than 25 cm and have polyhydramnios. The condition can result in:

• Early labor and delivery (preterm delivery)
• Cesarean delivery
• Increased bleeding after delivery
• Reduced growth in the baby
• Cord prolapse —The umbilical cord descends into the vagina before the baby.

Fetus in Utero, Amniotic Fluid

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Causes

About two-thirds of the time, the cause of polyhydramnios is not known. One-third of the time, a cause is found. Some causes are related to the mother and others are related to the baby.

Conditions that can cause polyhydramnios:

• Birth defects in the fetus, such as anencephaly
• Rh disease —a treatable condition that occurs when mother and baby have different blood types
• Diabetes in the mother
• Identical twins (twin-to-twin transfusion)

Risk Factors

The presence of a known cause of polyhydramnios (eg, diabetes in the mother) increases the risk of developing it.

Symptoms

Symptoms in the mother:

• Discomfort in the abdomen
• Trouble breathing due to crowding of the lungs (The large uterus in the abdomen pushes up your diaphragm.)

If you have mild polyhydramnios, you may not have any symptoms.

Diagnosis

Your doctor will ask about your symptoms and medical history. A physical exam will be done. You will probably be referred to a doctor who specializes in high risk obstetrics.

Your doctor may need pictures of your uterus and baby. This can be done with an ultrasound.

Your doctor may also need you to have tests of your body fluids. This can be done with:

• Amniotic fluid index
• Blood glucose
• Amniocentesis

Treatment

You will probably have more frequent prenatal visits and regular ultrasound tests. It is important to keep these appointments.

About half the time, polyhydramnios gets better without any treatment. In other cases, treating the cause of the increased amniotic fluid takes care of the problem. For example, diabetes treatment may make the polyhydramnios go away.

Your doctor will suggest a treatment plan based on your due date and the amount of amniotic fluid. If treatment is needed, options include the following:

• Removal of amniotic fluid—Your doctor may do a procedure to remove some amniotic fluid. This is similar to amniocentesis, but more fluid is removed.
• Medicine—Indomethicin may be used to decrease amniotic fluid. It is effective about 90% of the time, but cannot be used in the last eight weeks of pregnancy.

Prevention

The only way to prevent polyhydramnios is to treat the cause. Getting regular check-ups while you are pregnant can help find the problem early.