Polyhydramnios (Too Much Amniotic Fluid)

Can too much of a good thing be bad? When it comes to amniotic fluid, the answer is, yes. This protective liquid is crucial to fetal survival and development in the womb. But too much amniotic fluid (polyhydramnios) can be dangerous.

Below, we’ll tell you why this is true. We’ll also explain what complications can come from excessive amniotic liquid. 

Monitoring amniotic fluid with ultrasound.

What is Amniotic Fluid? 

Everyone knows humans need air to breathe. But at the fetus stage, humans don’t breathe in air, but amniotic fluid. 

Here are some other important functions of amniotic fluid:

  • Acts like a cushion to protect the baby from injury
  • Protects against infections
  • Keeps womb temperature consistent
  • Ensures the umbilical cord doesn’t get compressed, cutting off the baby’s oxygen supply
  • Helps the baby’s lungs develop as they breathe the fluid in and out 
  • Lets the baby move around and develop their bones and muscles

Where does amniotic fluid come from? You may be surprised to read that it doesn’t just come from the mother. Yes, water from mom’s body does account for most of it– at first. But after week 20, the baby’s kidneys produce a great amount. This is because they swallow the fluid, and then excrete it as urine.

What is Polyhydramnios?

Polyhydramnios is when there’s too much amniotic fluid. It’s not a very common condition. According to the Mayo Clinic, it occurs in just 1 to 2% of pregnancies. 

At 36 weeks, there should be about 1 quart of amniotic fluid. Then the amount should start decreasing. If it doesn’t decrease, there could be a problem. 

Doctors measure the amount of fluid in two ways: amniotic fluid index (AFI) and maximum vertical pocket (MPV). In simple terms, they measure the uterus to estimate the fluid levels in each part of it. If the AFI measurement is more than 25 centimeters, a woman has polyhydramnios. 

What Causes Polyhydramnios?

What might cause there to be too much amniotic fluid? One of the main causes is gestational diabetes. This is when the mother becomes diabetic during pregnancy. 

Other times the culprit is fetal malformation. For example, there could be a problem with the gastrointestinal or urinary tract. Also, women who carry twins or multiples are at higher risk for developing polyhydramnios. 

Other reasons why this condition might develop include:

  • The fetus produces too much urine
  • The fetus has trouble swallowing the amniotic fluid
  • Maternal infections (such as syphilis)
  • Anemia in the fetus
  • Genetic abnormalities, such as Down syndrome 

Signs of Polyhydramnios

Women with too much amniotic fluid in the womb may experience no symptoms at all. Others might have abdominal pain because the excess fluid makes the uterus press on other organs. 

Here’s a short (non-exhaustive) list of other possible symptoms:

  • Stomach tightness
  • Constipation or trouble urinating
  • Enlarged vulva
  • Indigestion
  • Swelling, especially in hips, legs, and feet

It’s important to know that the symptoms above also correspond to other pregnancy complications. So you might have one or more of these symptoms, but not have polyhydramnios. 

Woman receives ultrasound early in pregnancy.

Treatment for Polyhydramnios

Slight polyhydramnios can go away on its own. But some cases require treatment. Or at the very least, constant monitoring. 

Here’s what you might expect your doctor to do when you have too much amniotic fluid:


The main course of action, especially for mild cases, is to monitor the mother and baby. The mother will need to get regular ultrasounds and nonstress tests. Women with polyhydramnios are at higher risk for preterm labor, so doctors will be on the lookout for signs of that. They should test for gestational diabetes as well. 


Your doctor might order a test called amniocentesis. This means they’ll collect a sample of amniotic fluid from the womb and analyze it in a laboratory. That way they can figure out what’s causing there to be too much amniotic fluid. Then they prescribe treatment for the cause.

Fluid Reduction

If it’s necessary, doctors might try to reduce the amount of amniotic fluid. There are a few ways to go about this:

  • Medication: Such as prostaglandin synthetase inhibitors or nonsteroidal anti-inflammatory drugs. 
  • Reduction Amniocentesis: This procedure involves draining the excess fluid.
Woman faces pregnancy scare because of too much amniotic fluid.

Complications from Having Too Much Amniotic Fluid

Most cases of polyhydramnios don’t cause long-term issues. But the earlier it starts, and the more fluid there is, the more dangerous it can become. 

Polyhydramnios might cause:

  • Postpartum bleeding (A uterus that has been stretched from too much amniotic fluid may not contract well, causing bleeding.) 
  • Premature labor
  • Long labor
  • Placental abruption
  • Umbilical cord prolapse (when the umbilical cord comes through the vagina before the baby)
  • The need for a Cesarean section 
  • Premature rupture of membranes (PROM) (When the pregnant woman’s “water” breaks but she’s not yet in labor)
  • Congenital abnormalities in the baby
  • Stillbirth

Not all complications from polyhydramnios are due to negligence. But it’s possible for a doctor to mishandle polyhydramnios. The baby and/or the mother can suffer injuries as a result. 
When that happens, your best ally is a birth injury lawyer. We can help you get the compensation you need and deserve. Schedule a free consultation with our experts here.