Oligohydramnios

Overview

What is oligohydramnios?

Oligohydramnios occurs during pregnancy when your amniotic fluid is lower than expected for your baby’s gestational age. Amniotic fluid is a water-like fluid that surrounds your baby in your uterus. It protects your baby from infection and umbilical cord compression and cushions their movements while they’re in the womb. Amniotic fluid also helps develop your baby’s digestive and respiratory system, as well as regulates their temperature.

Too little amniotic fluid can cause health problems in your baby or be a sign of an underlying condition. These conditions could affect your baby’s development or cause complications during labor and delivery.

How common is oligohydramnios?

Low amniotic fluid affects about 4% of people who are pregnant. It’s most common in the last three months of pregnancy. This rate rises to about 12% in people who are past their due date because amniotic fluid levels decrease after 40 weeks of pregnancy.

How much amniotic fluid do I have during pregnancy?

It depends on how many weeks pregnant you are. You begin making amniotic fluid about 12 days after conception. The amount of amniotic fluid you produce increases until its peak at 36 weeks of pregnancy. After that, your levels of amniotic fluid start decreasing.

Symptoms and Causes

What is the most common cause of oligohydramnios?

Several factors can contribute to low amniotic fluid, such as:

  • Congenital anomalies that affect your baby’s kidneys or urinary tract.
  • Problems with your placenta.
  • Going more than two weeks past your due date.
  • Hypertension or preeclampsia.
  • Diabetes.
  • Dehydration.
  • Prelabor rupture of the membranes.
  • Twin-to-twin transfusion syndrome.

What are the signs of low amniotic fluid?

You may not know you have low amniotic fluid. However, your healthcare provider may suspect it if:

  • You’re leaking fluid from your vagina.
  • Your uterus measures small.
  • You don’t feel your baby move enough.
  • You’re not gaining enough weight.

You’re also at an increased risk for low amniotic fluid if you’ve had low amniotic fluid in prior pregnancies.

What are the complications of oligohydramnios?

Low amniotic fluid in the first six months of pregnancy is generally more dangerous. These complications could include:

If you’re diagnosed with oligohydramnios in the last trimester (weeks 28 to 40) of pregnancy, complications could include:

  • Umbilical cord compression.
  • Fetal growth restriction.
  • Respiratory issues or underdeveloped lungs.
  • Increase risk of Cesarean delivery.
  • Need for an early delivery.
  • Increased risk for infection if your water has broken too early.

Diagnosis and Tests

How is oligohydramnios diagnosed?

If you have any signs of low amniotic fluid, your healthcare provider will measure the amount of amniotic fluid in your uterus using an ultrasound. If the amount of fluid is less than the recommended amount for the gestational age of your fetus, you may have oligohydramnios.

There are two ways to measure amniotic fluid: amniotic fluid index (AFI) or maximum vertical pocket (MPV).

Management and Treatment

What is the treatment of oligohydramnios?

It depends on how far along you are in your pregnancy and if you’ve been diagnosed with other pregnancy complications. If you’re close to full term (37 weeks of pregnancy), your healthcare provider may decide that inducing labor early is the safest option for your baby.

Your healthcare provider may monitor you more closely with extra prenatal visits, ultrasounds, non-stress tests and a biophysical profile.

Prevention

How can I prevent oligohydramnios?

There isn't anything you can do to prevent oligohydramnios. Attend all prenatal checkups and be honest with your healthcare provider about your symptoms and medical history. Knowing if you’re at risk for low amniotic fluid is your best chance for treating the condition.

Outlook / Prognosis

Can a baby survive oligohydramnios?

Yes, your baby will likely be born healthy and happy. Low amniotic fluid can be serious, but in most cases, it’s highly treatable.

Living With

Can drinking water increase amniotic fluid?

Maybe. Some studies show that drinking water can help increase amniotic fluid levels in people who are pregnant. Talk to your healthcare provider about increasing your water intake as a treatment for oligohydramnios.

When should I see my healthcare provider?

Call your healthcare provider if you experience any of the following:

  • Leaking large amounts of amniotic fluid from your vagina.
  • Vaginal bleeding.
  • Cramps or pelvic pain.
  • Contractions.
  • Feeling your baby move less.

A note from Cleveland Clinic

Low amniotic fluid or oligohydramnios is a potentially serious condition. It can cause complications with your pregnancy and affect your baby’s growth. Try to remain calm, though — most people who are diagnosed with low amniotic fluid go on to have healthy babies. Your healthcare provider will monitor you closely and work with you to determine the safest treatment plan. Attending all prenatal visits and sharing your pregnancy symptoms is the best way to detect potential issues.

Last reviewed by a Cleveland Clinic medical professional on 12/14/2021.

References

  • American Pregnancy Association. Low Amniotic Fluid Levels: Oligohydramnios. (https://americanpregnancy.org/healthy-pregnancy/pregnancy-complications/oligohydramnios/) Accessed 12/14/2021.
  • Lord M, Marino S, Kole M. Amniotic Fluid Index. (https://www.ncbi.nlm.nih.gov/books/NBK441881/) [Updated 2021 Jan 6]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Accessed 12/14/2021.
  • March of Dimes. Oligohydramnios. (https://www.marchofdimes.org/complications/oligohydramnios.aspx) Accessed 12/14/2021.
  • Merck Manuals. Problems With Amniotic Fluid. (https://www.merckmanuals.com/home/women-s-health-issues/complications-of-pregnancy/problems-with-amniotic-fluid?query=oligohydramnios) Accessed 12/14/2021.

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