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Medically reviewed by Last updated on Jan 5, 2023.

What is polyhydramnios?

Polyhydramnios is a condition that causes you to have too much amniotic fluid during pregnancy. This fluid surrounds your unborn baby in the womb. Polyhydramnios is most common in the third trimester.

Why is amniotic fluid important during pregnancy?

Amniotic fluid helps your baby grow and develop normally. The fluid does the following during pregnancy:

  • Protects your baby from injury
  • Protects the umbilical cord and keeps it from being pinched
  • Helps your baby's lungs develop, and helps him or her exercise his or her muscles and digestive system
  • Keeps your baby's temperature regular and protected from infection
  • Prevents contractions from starting early

What causes polyhydramnios?

Amniotic fluid starts to develop in the womb soon after conception. The fluid contains mainly urine from the unborn baby by the end of the pregnancy. The baby normally swallows amniotic fluid and then urinates. This keeps the fluid level steady throughout pregnancy. The following can cause polyhydramnios:

  • A condition that causes your baby to urinate too much
  • Swallowing problems, such as from a cleft palate or a tumor, that prevent your baby from swallowing amniotic fluid
  • A birth defect, such as spina bifida or Down syndrome
  • Anemia, infection, or a heart problem in the baby
  • Pregnancy with more than one baby
  • Mother and baby have different blood types
  • Mother has diabetes

What are the signs and symptoms of polyhydramnios?

  • More weight gain than expected in the mother
  • Swelling in the legs, shortness of breath, or less urination than usual in the mother
  • Mother's abdomen is tight or shiny, or larger than expected for the trimester
  • More amniotic fluid than expected for the trimester

How is polyhydramnios diagnosed?

Your healthcare provider will examine you and ask about your symptoms. Tell him or her if your baby is moving less than usual, or if any fluid leaked from your vagina. Tell him or her about all medicines you are taking. You may need any of the following:

  • Ultrasound pictures are used to find the amount of amniotic fluid in the womb. The pictures may also show the baby's size. His or her kidneys and urinary tract will be checked. Moving ultrasound pictures are used to check blood flow through arteries in the baby's kidneys and through the placenta.
    Pregnancy Ultrasound
  • Amniocentesis is a procedure used to take a sample of amniotic fluid from the womb. The fluid contains cells that can be tested for birth defects and other problems.
  • A glucose challenge test is used to find the amount of glucose (sugar) in your blood. An increased amount may be a sign of gestational diabetes (diabetes during pregnancy). You will fast overnight and then drink a sweet liquid. Your blood sugar level will be tested every hour for 3 hours in a row. A high level in at least 2 of the tests is a sign of gestational diabetes.
  • A fetal nonstress test is used to check how the baby's heartbeat changes when he or she moves. You will wear a device on your abdomen. The device measures your baby's heart rate. You may need to eat or drink something to make your baby more active.
  • A biophysical profile is a test that checks the baby's breathing and movement. It also checks for the amount of amniotic fluid in the womb.

How is polyhydramnios treated?

Mild polyhydramnios may not need to be treated. If it is severe, you may need any of the following:

  • Amnioreduction is a procedure used to remove extra amniotic fluid.
  • Medicine may be given to reduce the amount of urine your baby produces.
  • Delivery may be recommended if your baby is close to full term.

What can I do to care for myself until delivery?

  • Elevate your head. Keep your head and shoulders propped up when you are lying down. This position will help you breathe deeply and prevent shortness of breath.
  • Get more rest. Your healthcare provider may tell you to alternate rest with activity. Activity improves your circulation and breathing.
  • Drink liquids as directed. Liquids can help prevent the amniotic sac from rupturing (tearing). This is called premature rupture of membranes (PROM). Amniotic fluid can leak out of a torn amniotic sac.

What are the risks of polyhydramnios?

Your water may break early, and your baby may be born prematurely. He or she may grow more than expected. The placenta may pull away from the womb before delivery. The umbilical cord may drop into your vagina before the baby. This can prevent your baby from getting enough oxygen during delivery. You may need a cesarean section (C-section). You may have heavy bleeding after delivery.

How can I lower my risk for polyhydramnios in a future pregnancy?

You may not be able to prevent polyhydramnios. The following may lower the risk:

  • Do not smoke. Nicotine increases the risk for problems with your pregnancy and your baby's health. Do not use e-cigarettes or smokeless tobacco in place of cigarettes or to help you quit. They still contain nicotine. Ask your healthcare provider for information if you currently smoke and need help quitting.
  • Eat a variety of healthy foods. Healthy foods include fruits, vegetables, low-fat dairy products, lean meats, and beans. Healthy foods can help you gain a healthy amount of weight during pregnancy, and prevent diabetes.
    Healthy Foods
  • Take prenatal vitamins as directed. The vitamins should contain at least 4,000 micrograms of folic acid. Folic acid helps prevent birth defects such as spina bifida. Your healthcare provider can help you choose a prenatal vitamin that is right for you.
    Sources of Folic Acid
  • Control diabetes or other medical conditions. Diabetes can cause problems for your baby, such as too much weight gain. If you have diabetes, work with your healthcare provider to manage your blood sugar levels before and during your next pregnancy.

When should I seek immediate care?

  • You have clear fluid leaking from your vagina.
  • You have heavy bleeding or any bleeding from your vagina for more than 24 hours.
  • You have vision changes or problems, such as blurred vision.

When should I call my obstetrician?

  • Your baby is moving less than usual.
  • You gain weight rapidly, or you have swelling in your legs or face.
  • You have a fever or chills.
  • You have contractions before you are due.
  • You have cramps, pressure in your abdomen, or a low backache.
  • You have questions or concerns about your condition or care.

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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