Problems With Amniotic Fluid

(Polyhydramnios; Hydramnios; Oligohydramnios)

ByAntonette T. Dulay, MD, Main Line Health System
Reviewed/Revised Apr 2024
VIEW PROFESSIONAL VERSION
GET THE QUICK FACTS

Amniotic fluid is the fluid that surrounds the fetus in the uterus. The fluid and fetus are contained in membranes called the amniotic sac. Problems with amniotic fluid include

  • Too much amniotic fluid for the length of the pregnancy

  • Too little amniotic fluid for the length of the pregnancy

  • Infection of the fluid, amniotic sac, and/or placenta (called an intraamniotic infection)

Too much amniotic fluid

Too much amniotic fluid (polyhydramnios or hydramnios) stretches the uterus and puts pressure on the diaphragm of pregnant women.

Too much fluid may accumulate because of the following:

However, almost half the time, the cause is unknown.

Too much amniotic fluid can lead to several problems:

Too little amniotic fluid

Causes of too little amniotic fluid include the following:

In many cases, the cause is unknown.

Too little amniotic fluid (oligohydramnios) can also cause problems, such as the following:

  • Intrauterine growth restriction: Fetus has not grown as much as expected

  • Limb and facial deformities (if the amount of fluid is greatly reduced and begins early in the pregnancy)

  • Delayed or incomplete lung maturation

  • Inability of the fetus to tolerate labor, leading to the need for cesarean delivery

  • Fetal death

Symptoms of Amniotic Fluid Problems

Usually, having too much or too little amniotic fluid does not cause symptoms in the woman. The woman may sense that the fetus is not moving as much as earlier in the pregnancy. Sometimes, when the amount of amniotic fluid is excessive, women have difficulty breathing or painful contractions before their due date.

Disorders causing or contributing to too much or too little amniotic fluid may cause symptoms.

Diagnosis of Amniotic Fluid Problems

  • A doctor's evaluation

  • Ultrasonography

  • Tests to identify the cause

Doctors may suspect too much or too little amniotic fluid when the uterus is too large or too small for the length of the pregnancy or when the fetus is not moving as much as expected.

Sometimes the problem is incidentally detected during ultrasonography. If a problem is detected, doctors can use ultrasonography to determine how much amniotic fluid is present.

If doctors detect too much or too little amniotic fluid, they check for a possible cause. For example, they may examine the vagina and cervix to determine whether the membranes around the fetus have ruptured too soon.

Blood tests may be done to check for disorders that can affect amniotic fluid (such as diabetes). Ultrasonography and other tests (possibly amniocentesis) may be done to check for birth defects and genetic abnormalities in the fetus.

Treatment of Amniotic Fluid Problems

  • Ultrasonography to monitor the fetus's growth and to measure amniotic fluid levels

  • Monitoring of the fetus's heart rate

  • Treatment of any underlying disorders

  • Sometimes removal of amniotic fluid

  • Delivery

Ultrasonography is done regularly to monitor how much the fetus is growing and to measure the amniotic fluid levels. The fetus’s heart rate is also regularly monitored when the fetus is lying still and as it moves. This test is done to check on the fetus's well-being (called nonstress testing).

Any underlying disorders, such as diabetes and high blood pressure, are treated.

When there is too much amniotic fluid, doctors rarely remove the excess fluid. However, the amniotic fluid can be removed with a needle through the woman's abdomen when

  • Labor begins early

  • The mother is having severe problems

When there is too much amniotic fluid, doctors plan to deliver the baby at about 39 weeks in certain cases.

When there is too little amniotic fluid, most experts may recommend delivery between 36 and 37 weeks depending on how the fetus is doing.

quizzes_lightbulb_red
Test your KnowledgeTake a Quiz!
Download the free MSD Manual App iOS ANDROID
Download the free MSD Manual App iOS ANDROID
Download the free MSD Manual App iOS ANDROID