What is Polyhydramnios (too much amniotic fluid)?

Polyhydramnios refers to a condition in which there is too much amniotic fluid.  Around 2% of pregnant women have polyhydramnios.  Typically polyhydramnios is mild and is a result of a gradual buildup of fluid during the second half of pregnancy.  In more than half of the cases, polyhydramnios goes away by itself.  However, polyhydramnios if it remains can often result in preterm delivery.

Polyhydramnios and Oligohydramnios (too little amniotic fluid) can be diagnosed via ultrasound.  Doctors measure the depth of amniotic fluid in four sections of the uterus and add them together.  This gives them a number known as AFI or amniotic fluid index.  If the AFI is less than 5 centimeters, the pregnant woman has oligohydramnios.  If the AFI is over 25 cm, she has polyhydramnios.

Birth defects of the central nervous system, gastrointestinal tract or bladder and kidneys are the most common causes of polyhydramnios.  This condition can cause complications during pregnancy such as preterm rupture of the membranes, preterm birth, umbilical cord accidents, placental abruption, poor growth of the baby and stillbirth.  Women with polyhydraminos are more likely to have a cesarean delivery and to have severe bleeding after delivery.

The causes of polyhydramnios are not completely understood.  Women who have chronic diabetes seem to have increased risk, though they seem to also have fewer complications as a result of polyhydramnios.  If your physician thinks you may be at risk for polyhydramnios, you will likely need further testing and monitoring of your AFI.

Treatment for polyhydramnios may include removing some amniotic fluid or using medications that will reduce fluid levels.

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