Polyhydramnios (pol-e-hi-DRAM-nee-os) is the excessive accumulation of amniotic fluid — the fluid that surrounds the baby in the uterus during pregnancy. Polyhydramnios occurs in about 1 to 2 percent of pregnancies.
Most cases of polyhydramnios are mild and result from a gradual buildup of amniotic fluid during the second half of pregnancy. Severe polyhydramnios may cause shortness of breath, preterm labor, or other signs and symptoms.
If you're diagnosed with polyhydramnios, your health care provider will carefully monitor your pregnancy to help prevent complications. Treatment depends on the severity of the condition. Mild polyhydramnios may go away on its own. Severe polyhydramnios may require closer monitoring.
Polyhydramnios symptoms result from pressure being exerted within the uterus and on nearby organs.
Mild polyhydramnios may cause few — if any — signs or symptoms. Severe polyhydramnios may cause:
Your health care provider may also suspect polyhydramnios if your uterus is excessively enlarged and he or she has trouble feeling the baby.
Some of the known causes of polyhydramnios include:
Often, however, the cause of polyhydramnios isn't clear.
Polyhydramnios is associated with:
The earlier that polyhydramnios occurs in pregnancy and the greater the amount of excess amniotic fluid, the higher the risk of complications.
If your health care provider suspects polyhydramnios, he or she will do a fetal ultrasound. This test uses high-frequency sound waves to produce images of your baby on a monitor.
If the initial ultrasound shows evidence of polyhydramnios, your health care provider may do a more detailed ultrasound. He or she will estimate the amniotic fluid volume (AFV) by measuring the single largest, deepest pocket of fluid around your baby. An AFV value of 8 centimeters or more suggests polyhydramnios.
An alternative way of measuring amniotic fluid is measuring the largest pocket in four specific parts of your uterus. The sum of these measurements is the amniotic fluid index (AFI). An AFI of 25 centimeters or more indicates polyhydramnios. Your health care provider will also use a detailed ultrasound to diagnose or rule out birth defects and other complications.
Your health care provider may offer additional testing if you have a diagnosis of polyhydramnios. Testing will be based on your risk factors, exposure to infections and prior evaluations of your baby. Additional tests may include:
If you're diagnosed with polyhydramnios, your health care provider will closely monitor your pregnancy. Monitoring may include the following:
Mild cases of polyhydramnios rarely require treatment and may go away on their own. Even cases that cause discomfort can usually be managed without intervention.
In other cases, treatment for an underlying condition — such as diabetes — may help resolve polyhydramnios.
If you experience preterm labor, shortness of breath or abdominal pain, you may need treatment — potentially in the hospital. Treatment may include:
After treatment, your doctor will still want to monitor your amniotic fluid level approximately every one to three weeks.
If you have mild to moderate polyhydramnios, you'll likely be able to carry your baby to term, delivering at 39 or 40 weeks. If you have severe polyhydramnios, your health care provider will discuss the appropriate timing of delivery, to avoid complications for you and your baby.
Polyhydramnios can be a worrisome finding during pregnancy. Work with your pregnancy care provider to ensure that you and your baby receive the best possible care.
You're likely to start by talking with your pregnancy care provider. Here's some information to help you get ready for your appointment and what to expect from your doctor.
Before your appointment:
Preparing a list of questions will help you make the most of your time with your doctor. For polyhydramnios, some basic questions to ask include:
Your doctor will likely perform a physical exam and run some tests, including an ultrasound exam. He or she may also ask you a number of questions, such as:
© 1998-2021 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved.