What is oligohydramnios?

In this condition, there is too little amniotic fluid around your baby during pregnancy. This occurs in only about 4% of pregnancies.  

Your baby needs amniotic fluid to grow. This watery fluid is inside the amniotic sac (membrane). It’s sometimes called the bag of waters. Your baby stays in this fluid for all of pregnancy. It helps to cushion and protect your baby. Amniotic fluid also helps your baby’s lungs, kidneys, and gastrointestinal (GI) tract grow.

The fluid is made by your baby’s lungs and kidneys. Your baby swallows the fluid and passes it out as urine. The waste is taken away through your placenta.  

Pregnant people normally have about one-half to 1 quart (500 ml to 1,000 ml) of amniotic fluid. Too much or too little amniotic fluid can cause problems. These issues can affect how your baby develops. They can also cause pregnancy complications. Or the amount of amniotic fluid may be a sign of another issue.

What causes oligohydramnios?

This condition may happen for several reasons. It may be due to not making enough fluid. Or it may be caused by problems that lower the amount of fluid. Oligohydramnios may be due to:

• Your water breaking before you go into labor

• Poor fetal growth

• Your pregnancy going past your due date

• Birth defects (kidney and urinary tract problems may be likely)

• You are pregnant with identical twins who share a placenta (called twin-to-twin transfusion syndrome)

What are the symptoms of oligohydramnios?

Symptoms can occur a bit differently in each pregnancy. They can include:

• Leaking of amniotic fluid, which may be caused by the sac breaking

• Not enough amniotic fluid seen on ultrasound

• Uterus is smaller than expected for how far along you are in pregnancy

These symptoms may be caused by other conditions. See your healthcare provider for a diagnosis.

How is oligohydramnios diagnosed?

Your healthcare provider will look at your health history. They will also give you an exam. The provider may spot this condition on an ultrasound during pregnancy. They will measure pockets of fluid to check the amount.

The ultrasound can show how well your baby is growing. It can also show the structure of your baby’s kidneys and urinary tract, and show urine in your baby’s bladder. You may need a special type of ultrasound (Doppler flow study) to check blood flow through your baby’s kidneys and the placenta.

How is oligohydramnios treated?

The goal of treatment is to keep you pregnant for as long as it’s safe. Treatment may also make you more comfortable.

Treatment will depend on your symptoms, pregnancy, and general health. It will also depend on how bad the condition is. Treatment may include:

• Monitoring. This means closely watching the amount of amniotic fluid.

• Regular checkups. Your healthcare provider may want to see you more often.

• Amnioinfusion. In this procedure, a special fluid is inserted into the amniotic sac. This is done to add fluid. You may need this if you’re in labor and your water has broken. You won’t have this done if you’re not in labor.  

• Delivering the baby. If problems are too risky for you or your baby, you may need to have your baby early.

What are possible complications of oligohydramnios?

Your baby needs amniotic fluid for their lungs to develop. Too little fluid for a long time may cause abnormal or incomplete development of your baby’s lungs. This is called pulmonary hypoplasia. 

Too little fluid may also keep your baby from growing well. This condition can also put pressure on the umbilical cord. This may prevent your baby from getting enough oxygen and nutrients. Too little fluid may also cause your baby to get their first bowel movement (meconium) in their lungs.

Key points about oligohydramnios

• In this condition, there is too little amniotic fluid around your baby in pregnancy.

• It can be caused by your water breaking too early. It can also be from staying pregnant past your due date. It may also happen for other reasons.  

• Having too little fluid can affect how your baby develops.

• Your healthcare provider may spot this condition during an ultrasound in pregnancy.

• Your treatment will depend on how little fluid you have. It will also depend on how it’s affecting your pregnancy. 

Next steps

Tips to help you get the most from a visit to your healthcare provider:

• Know the reason for your visit and what you want to happen.

• Before your visit, write down questions you want answered.

• Bring someone with you to help you ask questions and remember what your provider tells you.

• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

• Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.

• Ask if your condition can be treated in other ways.

• Know why a test or procedure is recommended and what the results could mean.

• Know what to expect if you do not take the medicine or have the test or procedure.

• If you have a follow-up appointment, write down the date, time, and purpose for that visit.

• Know how you can contact your provider if you have questions, especially after office hours or on weekends.