5 Causes Of High Amniotic Fluid (Polyhydramnios) In Pregnancy

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The amniotic fluid acts as a cushion to the baby in your womb. It also helps in the development of the baby’s lungs, digestive tract, and muscles.  Too high or too little fluid volume may sometimes cause complications in pregnancy.

In this MomJunction post, we will help explain the significance of amniotic fluid.

What Is Polyhydramnios?

Excess build-up of amniotic fluid around the growing baby is termed as polyhydramnios or hydramnios (1). According to the Fetal Medicine Foundation, UK, this condition occurs in one out of 100 cases (2).

Ideally, the doctor checks the amniotic fluid levels through an ultrasound. The normal volume of amniotic fluid should be between 500 and 1000ml. If it goes beyond this, there could be certain problems in the pregnancy.

What Are The Causes Of Polyhydramnios?

In most cases, it is not clear why the amniotic fluid levels increase. However, some possible causes are:

  1. Diabetes: According to the University of Rochester Medical Center, women who had diabetes before pregnancy or have gestational diabetes could be at risk of hydramnios (1).

    Diabetes can cause high amniotic fluid

    Image: iStock

  1. Twin-to-twin syndrome: In this rare condition, the twins share a placenta. The baby that sends blood to its twin will have less amniotic fluid around, and the baby that receives it will have a high volume of amniotic fluid or polyhydramnios (3).
  1. Birth defects: Congenital anomalies such as duodenal atresia or conditions relating to the heart or lungs (hydrops fetalis) may also lead to building up of the fluid, causing polyhydramnios (4).
  1. Others: Some other conditions, such as viral infections, fetal anemia, and kidney or heart problems, can also be responsible for increased amniotic fluid levels in the uterus (5) (4).

    Heart problems can cause high amniotic fluid

    Image: Shutterstock

  1. Most commonly, however, there is no cause for higher amniotic fluid, termed, “idiopathic”.
Point to consider
Polyhydramnios may also happen if the baby has an Rh-positive blood type and the mother has an Rh-negative blood type. The baby may develop Rh-factor or Rh-disease, a type of anemia. It may also lead to polyhydramnios (10).

Symptoms Of Polyhydramnios

Excess amniotic fluid can put pressure on the uterus and nearby organs. This could cause (2) (6).

  • Discomfort in the stomach

    Excess amniotic fluid can put pressure on the uterus

    Image: iStock

  • Shortness of breath
  • Contractions
  • Swelling in the abdominal wall and lower extremities
  • Change of fetal position
  • A uterus enlarged more than normal for that time in pregnancy.
Things to know
Swelling of the vulva, decreased urine production, constipation, heartburn, and abdominal tightness are some more symptoms of polyhydramnios (10).

Risks Related To Excess Amniotic Fluid

Polyhydramnios could be mild, moderate, or severe. Severe polyhydramnios is associated with the following complications (2) (6).

  • Too much fluid can expand your uterus and result in preterm labor
  • Early rupture of the amniotic sac
  • When amniotic fluid leaks, there could be placental abruption (detachment of the placenta from the uterus)
  • Umbilical cord prolapse (when the umbilical cord drops into the vagina)
  • Heavy bleeding after birth
  • Stillbirth

Timely diagnosis could help prevent these risks.

Diagnosis Of Polyhydramnios

Ultrasound can help diagnose polyhydraminos

Image: Shutterstock

Based on the checkup and the symptoms displayed, the doctor will recommend a fetal ultrasound. If the results hint at excess amniotic fluid, a detailed ultrasound is done (6).

There are two ways to measure the volume of the amniotic fluid.

  • The latest method and most accurate is measuring the deepest vertical pocket of amniotic fluid, called the “DVP”. Normal range is greater than 2cm but less than 8cm.
  • The second method is AFI or amniotic fluid index, which is the sum of the largest pockets of different parts in the uterus. If this measurement is greater than 25cm, it suggests excess amniotic fluid volume.

How Can Polyhydramnios Be Treated?

Polyhydramnios rarely requires any treatment. However, scheduled ultrasounds are done to closely monitor the amniotic fluid index and the baby’s health.

Rarely occuring but in severe cases of polyhydramnios, a few treatments may be recommended to reduce the amniotic fluid level become symptomatic with shortness of breath or signs and symptoms of preterm contractions. Treatment options may differ depending on certain factors such as the severity of the condition, its cause, symptoms, and gestational age (8).

  1. Medications: Based on the cause of excess amniotic fluid in the uterus, doctors prescribe medicine to reduce the fluid. For instance, if hydramnios is due to a fetal condition, then medicine to treat that condition is prescribed. This, in turn, adjusts the fluid level.
Doctor may prescribe medicine to reduce excess amniotic fluid

Image: Shutterstock

  1. Amnioreduction: In this procedure, the doctor inserts a  needle inside the uterus to drain out the excess amniotic fluid. This procedure may cause a little discomfort in the abdomen.
  1. Delivery: In case of complications that seem risky for the mother’s or baby’s health, early delivery is scheduled.

Besides the treatment, following a few self-care measures can help.

Can Polyhydramnios Cause Birth Defects?

Polyhydramnios or too much amniotic fluid may rarely indicate that there could be a congenital anomaly or a birth defect in the baby, but it does not cause them.

If the doctor finds that there is too much amniotic fluid, an ultrasound or other tests could be done to analyze the risks. The treatment options are recommended based on the results.

Is Polyhydramnios Dangerous For The Baby?

A severe case of polyhydramnios could increase the risks of preterm labor, placental abruption, infections, and stillbirth. But proper diagnosis and treatments in time can help in cutting down these risks.

Frequently Asked Questions

1. Can too much amniotic fluid harm the baby?

In most cases, having too much amniotic fluid around your fetus will not affect your pregnancy. However, you will have a healthy baby without significant risks with extra medical check-ups (9).

2. How can I reduce my amniotic fluid naturally during pregnancy?

There are no natural ways to reduce excessive amniotic fluid (polyhydramnios) during your pregnancy other than clinical management. However, in mild cases of polyhydramnios, no intervention might be needed, while in moderate cases, bed rest can be helpful (10).

High amniotic fluid, also known as polyhydramnios, is a pregnancy issue discovered during routine prenatal checks with ultrasound. While the majority of cases of polyhydramnios are idiopathic, additional factors such as diabetes in the pregnant mother or birth abnormalities could be to blame. Stomach pain, abdominal contractions and swelling, dyspnea, and other symptoms may occur. However, since polyhydramnios is a rare illness, there is no reason to get alarmed. Even if your doctor detects or diagnoses you with the illness, getting treatment and care as soon as possible can help reduce the dangers.

Key Pointers

  • Polyhydramnios is a rare condition seen in one out of 100 cases.
  • Diabetes, twin-to-twin syndrome, congenital disabilities such as duodenal atresia, and fetal anemia are some causes of polyhydramnios.
  • Symptoms include shortness of breath, contractions, stomach discomfort, swelling of the legs or abdominal wall, etc..
  • Serious cases of polyhydramnios can increase the risk of premature labor, infections, placental abruptions, and stillbirth.


MomJunction's articles are written after analyzing the research works of expert authors and institutions. Our references consist of resources established by authorities in their respective fields. You can learn more about the authenticity of the information we present in our editorial policy.
1. Hydramnios; University of Rochester Medical Center
2. Polyhydramnios; The Fetal Medicine Foundation
3. Twin-to-twin transfusion syndrome; C. S. Mott Children’s Hospital Michigan Medicine
4. Polyhydramnios treatment at Midwest Fetal Care Center; Children’s Minnesota
5. Polyhydramnios; Darthmouth-Hitchcock
6. Polyhydramnios; NCH Healthcare System
7. Polyhydramnios; Spectrum Health The Medical Group
8. A. Hamza, D. Herr, E. F. Solomayer, and G. Meyberg-Solomayer; Polyhydramnios: Causes, Diagnosis and Therapy; Geburtshilfe und Fraueneilkunde (2013)
9. Polyhydramnios (too much amniotic fluid); NHS
10. Polyhydramnios: High Amniotic Fluid During Pregnancy; American Pregnancy Association
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