Polyhydramnios In Pregnancy: When There Is Too Much Amniotic Fluid

Polyhydramnios In Pregnancy: When There Is Too Much Amniotic Fluid

If you're found to have too much amniotic fluid at any point in your pregnancy, it's called polyhydramnios.

Polyhydramnios in pregnancy is a rare condition that happens when excess amniotic fluid accumulates in the uterus during pregnancy. 

Amniotic fluid is the fluid that surrounds your baby in your uterus (womb). During pregnancy, your baby needs amniotic fluid to grow.  Your baby stays in this fluid throughout pregnancy. It helps to cushion and protect your baby, and is also essential for your baby’s development.

During the first 14 weeks of your pregnancy, fluid passes from your circulatory system into the amniotic sac. Early in the second trimester, your baby starts to swallow the fluid and pass it out as urine (and the cycle goes on). The waste is taken away through your placenta.

Pregnant women normally have about 500 to 1,000 ml of amniotic fluid. Too much or too little amniotic fluid can can affect how your baby develops and/or cause pregnancy complications. 

If you're found to have too much amniotic fluid at any point in your pregnancy, it's called polyhydramnios.

Polyhydramnios occurs in about 1 to 2 percent of pregnancies. It can occur as early as 16 weeks, but it is usually seen in the later part of pregnancy.

Polyhydramnios is usually harmless, but in rare cases it can lead to serious pregnancy complications, especially if it occurs early on in the pregnancy, and depending on the amount of excess amniotic fluid.

polyhydramnios in pregnancy

Causes Of Polyhydramnios in Pregnancy

In many cases, the exact cause of polyhydramnios cannot be determined. 

Mild polyhydramnios can be caused by the gradual buildup of amniotic fluid over the course of the pregnancy.

Moderate to severe polyhydramnios may be caused due to:

  • A birth defect or congenital disability that affects the baby's gastrointestinal tract or central nervous system

Sometimes the baby’s ability to swallow may be impaired, due to a birth defect. 

While inside the womb, babies will swallow amniotic fluid and then urinate it out. This keeps the amount of amniotic fluid at a steady level. If the baby cannot swallow due to a genetic defect, amniotic fluid will build up.

  • Maternal diabetes

Elevated blood glucose levels can lead to an excessive buildup of amniotic fluid.

This can happen when the mother has diabetes before getting pregnant or becomes diabetic during pregnancy (gestational diabetes).

  • Being pregnant with twins or other multiples

Polyhydramnios is especially likely in the case of twin-to-twin transfusion syndrome, in which one twin has too little amniotic fluid while the other has too much.

  • Mismatched blood types between mother and baby

When a mother has Rh-negative blood type, and her baby has Rh-positive blood type, there is a risk of the baby developing, Rh-factor or Rh disease, a type of anaemia. This can cause, among other complications, polyhydramnios.

  • A problem with the baby’s heart rate

This includes anything from foetal arrhythmia, a faintness of heartbeat due to a large amount of amniotic fluid or a congenital heart defect.

  • Infection during pregnancy

  • A lack of red blood cells in the baby (foetal anemia)

polyhydramnios in pregnancy

Symptoms Of Polyhydramnios in Pregnancy

There may not be any symptoms in the case of mild polyhydramnios.

Moderate to severe Polyhydramnios may cause the following symptoms, due to the enlarged uterus exerting pressure on the other organs:

  • Difficulty breathing
  • Swelling in the lower extremities and abdominal wall
  • Uterine discomfort or contractions
  • Swelling of the vulva
  • Decreased urine production
  • Swollen feet
  • Constipation
  • Heartburn
  • Feeling huge or tightness in the belly
  • Foetal malposition, such as breech presentation

Complications from Polyhydramnios

Mild polyhydramnios usually does not cause complications during pregnancy. But in severe cases, there are certain risks, including:

  • Premature rupture of membranes — when your water breaks early
  • Premature Birth
  • Excess foetal growth
  • Placental abruption (premature separation of the placenta from the wall of the uterus)
  • Postpartum haemorrhage - Heavy bleeding due to lack of uterine muscle tone after delivery
  • Umbilical cord prolapse (the cord falling out of the vagina before the baby)
  • Foetal malposition such as breech presentation
  • Stillbirth

polyhydramnios in pregnancy

Testing For Polyhydramnios in Pregnancy

If your doctor suspects that you have polyhydramnios, he or she will perform a more detailed ultrasound to estimate how much amniotic fluid is inside your uterus, and to look for any foetal abnormalities.

Your doctor may also perform the following tests:

  • Glucose challenge test (for gestational diabetes)
  • Amniocentesis (sampling of amniotic fluid to test the baby for genetic abnormalities or defects)
  • Non-Stress Test (to check for abnormalities in the baby’s heart rate)
  • Doppler ultrasound (a stronger ultrasound that can see the baby’s circulatory system)

Treatment For Polyhydramnios

If you have polyhydramnios, you will usually have ultrasounds weekly or more often to check amniotic fluid levels. You may also have tests to check your baby’s health.

Treatment for polyhydramnios depends on the cause of the condition, and how severe it is. Mild cases of polyhydramnios usually do not require any treatment, and may go away on its own.

Severe polyhydramnios may require closer monitoring, especially from week 32 of pregnancy.

Cases of moderate polyhydramnios found later in pregnancy can be treated with bed rest. Laying horizontal and resting is recommended to delay any preterm labour as long as possible.

In more severe cases, polyhydramnios can be treated by regularly draining amniotic fluid from the uterus using a large needle. 

This procedure is called amnioreduction, and carries a risk of complications, so your doctor will only recommend it if the danger of continuing the pregnancy with untreated polyhydramnios is greater than the risk of draining the fluid.

If your doctor determines that your polyhydramnios is a result of your baby’s heart rate, he or she might give you medication to correct the heart rate.

Polyhydramnios can also be treated with a medication that reduces the amount of urine the foetus produces. 

In some cases of severe polyhydramnios, your doctor may decide that the best course of action is to induce labour early, at 37 weeks, or even sooner.

Doctors may also consider a caesarean delivery if they feel that the baby is too large, or a breech or vaginal birth is too risky.

If you have polyhydramnios in pregnancy, it is important to follow your doctor’s advice to help you have a safe delivery.

Also READ: "I have severe pubic bone pain during pregnancy. What should I do?"

(Source: AmericanPregnancy, MayoClinic, Stanford Children’s Health, NHS)

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Written by

Jaya

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