Polyhydramnios (Hydramnos)

Definition - What does Polyhydramnios (Hydramnos) mean?

Polyhydramnios is a condition related to pregnancy where there is a build up of the fluid that surrounds the baby in the uterus, called as the amniotic fluid. It leads to several complications like premature birth, placental abruption, and fetal abnormalities.

Hydramnios occurs at a rate of 1-2% in pregnant women. The diagnosis is made during pregnancy by an ultrasound examination that measures the amniotic fluid volume. The outcome of polyhydramnios varies with its cause and severity.

Polyhydramnios may also be referred to as hydramnios.

FertilitySmarts explains Polyhydramnios (Hydramnos)

During the initial 14 weeks of pregnancy, fluid from the mother's body passes into the amniotic sac or the bag of waters. When fetal kidneys start to function sometime around week 16, the fetus begins to swallow this fluid, which travels through the kidneys, and excreted as urine. The amniotic fluid is then re-swallowed and recycled; this cycle repeats every few hours.

With an accumulation in the amniotic fluid, symptoms experienced may include having unusual abdominal discomfort, difficulty breathing, swelling in the feet and ankles, and increased back pain. This is because the enlarging uterus compresses the organs and lungs. A healthcare practitioner may suspect this condition if the uterus is growing at a faster rate than would be expected.

Polyhydramnios may be caused by:

Maternal causes:

  • Diabetes: Inadequately controlled diabetes can lead to hydramnios. Maternal blood glucose passes into the fetus leading to high blood sugar levels and resultant excessive production of urine in your baby
  • Twin or multiple pregnancies: Being pregnant with twins or multiples increases the risk for hydramnios. The cause of polyhydramnios in multiple pregnancies is usually twin-to-twin transfusion syndrome, in which one twin is unable to produce enough amniotic fluid while the other creates too much

Fetal causes:

Anomalies that hinder the swallowing of the fluid by the fetus while the kidneys continue to produce more urine from the swallowed fluid can likely result in polyhydramnios. These include:

  • Esophageal or duodenal atresia
  • Cleft lip or palate
  • Pyloric stenosis
  • Any other kind of blockage in the gastrointestinal tract
  • Certain neurological problems, such as neural tube defects
  • Chromosomal abnormalities such as Down syndrome also interfere with the proper swallowing of the fluid
  • Transplacental infections like TORCH

An amniotic fluid index (AFI) of greater than 24 cm (as measured by an ultrasound) establishes the diagnosis of polyhydramnios. Treatment includes withdrawing the excess fluid via amnioreduction or amniocentesis, and the use of medications like non-steroidal anti-inflammatory drugs (NSAIDs) to reduce the amniotic fluid volume.

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