Polyhydramnios- Excessive Amniotic Fluid During Pregnancy

5 min read

Written by Editorial Team

Editorial Team


A growing baby is fenced by the amniotic fluid in the womb. The amniotic fluid protects the growing fetus by acting as a cushion and prevents any kind of infection in the womb. It also makes the movement of the baby easier in the womb. This way it helps in musculoskeletal development.

It also helps with the development of lungs and different organ systems. What happens if the quantity of amniotic fluid increases abnormally during pregnancy? How does it affect the pregnancy? Continue reading to know more about polyhydramnios, a condition in which the amount of the amniotic fluid increases abnormally. pregnancy pillow

In This Article

What Is Polyhydramnios?

Polyhydramnios is an abnormal condition that happens during pregnancy caused by excess amniotic fluid. The increased levels of fluid can bring about several issues during different stages of pregnancy and delivery and can often lead to adverse pregnancy complications. Polyhydramnios is seen in around 1% of pregnancies.
The polyhydramnios can be either chronic, in which the buildup of amniotic fluid will progress slowly or can be acute, marked by the quick accumulation of amniotic fluid.

What Results In Polyhydramnios?

During the initial 14 weeks of gestation, the amniotic fluid is made from water and fluids taken in by the mother. After that, as the baby grows, the majority of the fluid actually consists of the baby’s urine. It breathes in the fluid, swallows some, and excretes the same as urine to maintain a balance. For various reasons, this delicate balance of amniotic fluid can be disturbed, resulting in too much or too little fluid buildup, either one of which is not a favorable condition for a healthy pregnancy.

Causes Of Polyhydramnios

causes of polyhydramnios

In about 50% of polyhydramnios cases, there are no definite reasons to pinpoint. More studies are required in this field for further information. In the other 50% of cases, polyhydramnios is due to either maternal, placental, or fetal tissues.

Here are the most significant reasons behind polyhydramnios.

1. Polyhydramnios Due to Placental Issues

Polyhydramnios can occur as a result of some issues related to the placenta such as:

Chorioangioma of placenta

Placental chorioangioma is the most common placental tumor and results in polyhydramnios

Twin-twin transfusion

This is an issue associated with multiple pregnancies (precisely the monochorionic twin pregnancies) in which, the babies share a single placenta. As a result, one child receives more blood than the other one. One who gets more blood is the recipient and one who gets less blood is the donor. The urine output of the recipient baby increases tremendously due to increased blood supply resulting in polyhydramnios

Polyhydramnios due to fetal issues

Polyhydramnios can occur as a result of some issues related to the fetus that affect the ability of the fetus to swallow and excrete amniotic fluid.

Fetal anemia

The lack of sufficient RBC (red blood cells) in the baby increases cardiac output. This, in turn, increases the production of fetal urine resulting in polyhydramnios

Gastrointestinal tract issues

Gastrointestinal tract obstruction in the fetus can result in polyhydramnios as it interferes with the proper intake and excretion of amniotic fluid

Fetal renal issues

Issues related to the fetal kidney can increase the urine production resulting in polyhydramnios

Chromosomal abnormalities

Sometimes, chromosomal abnormalities like Down syndrome are found to cause polyhydramnios

Fetal macrosomia

Excessive amniotic fluid can be caused due to fetal macrosomia. In this case, the baby is larger for its gestational period

Polyhydramnios Due to Maternal Issues

Some of the maternal issues that develop during pregnancy can lead to polyhydramnios.


If the blood sugar level of the mother is high, it will influence the baby. As a result, the baby produces more urine. This results in the increased volume of the amniotic fluid (polyhydramnios)


Various infections like rubella, parvovirus, etc. that affect the mother reach the fetus and due to this fetus may develop certain abnormalities that hinder the proper intake and excretion of amniotic fluid triggering polyhydramnios


Pregnancy-induced blood pressure increases the amount of the amniotic fluid resulting in polyhydramnios


Preeclampsia and polyhydramnios are closely related. Most of the mothers who develop preeclampsia are also found to experience polyhydramnios

Rhesus disease

Rhesus disease is a condition in which the antibodies in the mother’s blood destroy the baby’s blood cells, resulting in fetal anemia which is one of the major causes of polyhydramnios

Symptoms Of Polyhydramnios

Extreme swelling in ankles

Usually, the polyhydramnios has no significant symptoms. However, severe polyhydramnios shows certain symptoms as the increased amniotic fluid put pressure both inside and on the organs that are situated outside the uterus. The symptoms caused by severe polyhydramnios include:

Complications Due To Polyhydramnios

With excess amniotic fluid, there will be increased risks of:

Diagnosis Of Polyhydramnios

If the doctor doubts polyhydramnios, he will straight away go for an ultrasound. If needed he will go for a more detailed scan, in which, the amniotic fluid index is evaluated. This is done by measuring the four deepest pockets in four different areas of the uterus. If the total is or above 25 centimeters or a single pocket has fluid more than 8 cm deep, polyhydramnios is confirmed. Other tests like amniocentesis, glucose challenge test or karyotype are conducted to find the reason.

How To Manage The Polyhydramnios Condition?

Once polyhydramnios is confirmed, the baby and mother will be closely monitored. The non-stress test, fetal echocardiogram, Doppler ultrasound, biophysical profile, etc,  are done for close monitoring.
In addition, complete bed rest, avoiding long journeys (even short jerky ones), using pregnancy cushions to support the big belly, avoiding lying down position immediately after food, consumption of less spicy food, etc, are suggested to avoid further complications.

What Are The Treatment Options For Polyhydramnios?

Only acute polyhydramnios are usually treated. Whereas, the moderate ones only needed to be closely monitored. The treatment options are determined according to the severity and cause.

Some of the treatment options are:

  • Amnio reduction: Amnio reduction procedure is used to drain out excess amniotic fluid from the uterus
  • Medicine to decrease fetal urine production: Certain oral medicines are prescribed to decrease the production of fetal urine. Though this is not recommended after the 31st week of gestation
  • Medicines to regulate the fetal heart rate: In some cases, the doctor may prescribe medicines for stabilizing the baby’s heart rate

After treatment, the doctor will still want to monitor the amniotic fluid levels every one to three weeks.

Editorial Team,

With a rich experience in pregnancy and parenting, our team of experts create insightful, well-curated, and easy-to-read content for our to-be-parents and parents at all stages of parenting.Read more.

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