Polyhydramnios

Polyhydramnios (polyhydramnion, hydramnios) is a medical condition describing an excess of amniotic fluid in the amniotic sac. It is seen in 0.5 to 2% of pregnancies. It is typically diagnosed when the amniotic fluid exceeds 2000 mL.

The opposite to polyhydramnios is oligohydramnios, a deficiency in amniotic fluid.

Causes

A single case of polyhydramnios may have one or more causes. About 20% of cases are due to maternal diabetes mellitus, which causes fetal hyperglycemia and resulting polyuria (fetal urine is a major source of amniotic fluid). About another 20% of cases are associated with fetal anomalies that impair the ability of the fetus to swallow (the fetus normally swallows the amniotic fluid). These anomalies include:

• gastrointestinal abnormalities such as esophageal atresia, duodenal atresia, facial cleft, neck masses, and tracheoesophageal fistula
• chromosomal abnormalities such as Down's syndrome and Edwards Syndrome (which is itself often associated with GI abnormalities)
• neurological abnormalities such as anencephaly, which impair the swallowing reflex

In a multiple gestation pregnancy, the cause of polyhydramnios usually is twin-twin transfusion syndrome.

It can also be caused by some systemic medical conditions in the mother, including cardiac or kidney problems.

Additionally, chorioangioma of the placenta can also cause this condition.

Associated conditions

Fetuses with polyhydramnios are at risk for a number of other problems including cord prolapse, placental abruption and perinatal death. At delivery the baby should be checked for congenital abnormalities.

Treatment

In some cases, amnioreduction has been used in response to polyhydramnios.

See also

• Amniotic fluid index

References

External links