Polyhydramnios or Excess Amniotic Fluid

Any change in amniotic fluid during pregnancy, such as polyhydramnios, can bring complications and put the baby's life at risk.
Polyhydramnios or Excess Amniotic Fluid

Last update: 28 September, 2023

Polyhydramnios, better known as excess amniotic fluid, is an accumulation of the fluid that surrounds the baby during gestation and provides the fetus with all the necessary proteins for development.

However, when there is too much, it can lead to problems for the mother or fetus.

What causes polyhydramnios?

Although specialists aren’t always able to find out why it occurs for some women, according to research there are certain conditions that lead to a heightened risk for polyhydramnios. These include the following:

  • Multiple pregnancies. This can cause one fetus to have more amniotic fluid than the other.
  • Maternal diabetes
  • Large babies.
  • Neurological problems in the fetus, such as hydrocephalus, which can lead to difficulty swallowing.
  • Low fetal heart rate. 
  • Fetal malformations which may cause problems swallowing, and as a result, excess fluid in the womb.
  • Incompatible blood types between mother and baby. 
Polyhydramnios or Excess Amniotic Fluid

Signs and symptoms

Women who suffer from polyhydramnios often don’t present any symptoms, especially if the condition is light. However, if the condition becomes serious, the following symptoms may occur:

  • Difficulty breathing
  • Abdominal pain
  • Inflammation of the abdominal wall or lower extremities
  • Uterine contractions
  • Vomiting
  • A shinier or tighter abdomen, more than usual during the appropriate stage of pregnancy.

How can polyhydramnios be diagnosed?

The best way for a pregnant woman to know whether she is suffering from polyhydramnios is via an ultrasound measurement performed by a specialist.

This will give an approximation of the Amniotic Fluid Index (AFI), which shouldn’t be greater than 25 centimeters during the third trimester. If it’s greater, this indicates an excess, which can cause harm. 

After doing the complete ultrasound to look for fetal malformations, the doctor should identify whether the excess in amniotic fluid is due to genetic factors by verifying whether there is a family history. 

The doctor may also do some glucose tolerance tests, as well as tests for hemorrhages, anemia, and maternal serological tests.

Risk factors

There are serious risk factors that can increase problems during pregnancy as a result of polyhydramnios. It’s therefore important for mothers to go to all scheduled check-ups with their doctors throughout pregnancy. 

These are possible results:

  • Post-partum hemorrhage. A serious loss of blood after delivery.
  • Fetal death. Polyhydramnios can cause the baby to die after 20 weeks of pregnancy.
  • Premature delivery. This occurs when the baby is born before 37 weeks of pregnancy.
  • Detached placenta. This detachment is considered serious because the baby no longer receives oxygen and nutrients provided by the womb. This can lead to dangerous bleeding.
  • Poor fetal position. Normally the fetus is arranged head down, looking towards the mother’s spine. However, in cases of polyhydramnios, this position may be affected. The safest option in this case is a cesarean section.

What is the treatment?

If the polihydramnios is mild, no treatment is necessary. But once a doctor indicates that the case is severe, it’s vital to act quickly.

Some of the most effective treatments include: manual reduction of amniotic fluid, medication to reduce the baby’s urination, or cases when the due date is near, inducing delivery.

Likewise, it’s a good idea to begin prenatal monitoring at 32 weeks via a complete test. During the test it’s important to remain calm so that the results are precise and not affected in any way. Additionally, if the mother has diabetes, watch blood sugar levels to avoid fetal death.

Pregnancy without complications

Avoiding polihidramnios is impossible, as it appears without warning, whether due to some anomaly, heredity, or unknown causes. 

Therefore, it’s important for future mothers to take care during every phase of pregnancy to reduce the risks from this condition to the baby and their health in general.

Healthy habits, staying away from nicotine, and good nutrition will help mothers maintain a healthy weight. This reduces the risk of diabetes and provides vitamins that are important for correct fetal development.



All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Infogen. (2013). Alteraciones del líquido amniótico: Oligohidramnios, polihidramnios. Artículo perteneciente a  Infogen
  • Stanford Children’s Health. Problemas del líquido amniótico/hidramnios/oligohidramnios. Artículo perteneciente a Stanford Children’s Health

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.