Excessive Amniotic Fluid During Pregnancy

For babies to develop normally in the uterus, a balance in the production of amniotic fluid is necessary. An increase or deficiency can be risky and bring severe complications. Let's take a deeper look at this topic.
Excessive Amniotic Fluid During Pregnancy

Last update: 02 October, 2018

It’s estimated that 2% of pregnant women have an excessive amount of amniotic fluid. This is a condition called “Polyhydramnios.” It’s basically an alteration in the amniotic fluid at any stage of pregnancy, which can bring complications that may put the child’s life at risk.

In this article, we’ll be sharing with you what it is, how it’s diagnosed, and the possible causes of it.

What is polyhydramnios?

This refers to an increase in the amount of liquid contained in the amniotic sac. An adequate amount of it protects the baby, who beings to swallow and inhale it towards the second trimester of pregnancy.

This action enables the development of the lungs and digestive system. An increase in fluid indicates a failure in these mechanisms.

This is diagnosed through an ultrasound since it allows doctors to determine the amniotic fluid index. It’s done by calculating the depth of the fluid in four different sections of the uterus, to then add the obtained results.

In case of having a depth greater than 24 centimeters, it’s safe to say that the pregnant woman suffers from polyhydramnios.

Excessive Amniotic Fluid During Pregnancy

What is the average amount of amniotic fluid?

The amount of amniotic fluid can vary in each woman and increases as the pregnancy progresses. However, its peak point occurs towards the 32nd week, achieving stability until the 36th week. 

From then on it begins to go down, but never becomes extinct. It can reach approximate amounts of 800 milliliters to 1 liter. 

Causes of excessive amniotic fluid

In most cases, the causes of this are unknown by the medical community. Nonetheless, some doctors presume it’s due to an excessive production of liquid or inconvenience to be absorbed. Other probable causes are:

Gestational diabetes

There is a slight increase in this condition in women with diabetes and an inability to control blood sugar levels.

Fetal alterations

Another cause of excessive amniotic fluid is fetal malformations. An incorrect development of the esophagus, pancreas, duodenum, and even of the nervous system of the fetus increases the chances of suffering from polyhydramnios.

Other fetal alterations include:

  • Defects of the neural tube closure.
  • Hydrocephalus, holoprosencephaly or microcephaly, among others.
  • Cardiac disorders such as valvular disability and arrhythmias, among others.
  • Abnormalities in the renal system.
  • Disorders in the respiratory system.
  • Skeletal dysplasia, achondroplasia, and dwarfism.
  • Fetal anemia, which is due to an incompatibility of the child’s Rh factor or an infection. The main treatment for this condition involves a transfusion of intrauterine blood.

In most cases, doctors are able to detect these alterations with tests and special studies based on polyhydramnios. However, it’s very common to see large amounts of amniotic fluid in bigger fetuses.

Multiple pregnancies

Women who are pregnant with twins have a higher chance of suffering from excessive amounts of amniotic fluid. The danger increases when TTTS (Twin-twin transfusion syndrome) occurs.

This condition takes place when one of the fetuses produces more blood than the other and, because of the blood connections, a hemodynamic instability is generated.

Symptoms of having excessive amniotic fluid during pregnancy

It’s important to note that the symptoms may vary in each woman. In fact, many of them don’t even show any signs at all. There can be an increase in symptoms according to the severity of the case. They can be:

  • A precipitated growth of the uterus, which can cause shortness of breath.
  • Acute abdominal discomfort.
  • Contractions of the uterus.

It’s advisable to be alert since many of these symptoms can be confused with other pathologies. This is why it’s important to go see a doctor as soon as possible to get the correct diagnosis and on time.

Excessive Amniotic Fluid During Pregnancy

Risks of having excessive amniotic fluid

The risks can be proportional to the symptoms that the woman presents. A complication in this alteration can lead to premature birth, placental abruption, rupture of membranes, inconveniences with the umbilical cord, among others.

The risks of the baby involve low fetal growth, cesarean delivery, and occasionally, death.

The treatment in most cases aims to treat the cause and relieve the discomfort of the mother.

Having excessive amniotic fluid can lead to severe complications in pregnancy. However, frequent monitoring can reduce the chances of suffering from this condition and bring the pregnancy to a successful end.


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