POLYHYDRAMNIOS

Polyhydramnios is defined as an excess accumulation of amniotic fluid.

ULTRASOUND CRITERIA

• Largest vertical pocket of 8cm or more.
• Amniotic fluid index of >25cm / Tables and Graphs of Amniotic fluid index.

4 quadrant amniotic fluid index = 26 cm

• Amniotic fluid index at or above the 95th percentile for gestational age.
• Moderate polyhydramnios = largest vertical pocket of between 8 and 12cm

Single deepest vertical pocket of 8.3 cm and 10 cm

• Severe polyhydramnios = largest vertical pocket of >12cm.

Single deepest vertical pocket of 12 cm

There is an association between the amount of polyhydramnios that is present and the risk of a fetal anomaly being present. When the maximal vertical pocket is >16 cm the risk is exceedingly high.

At least 50% of all anomalous fetuses will have some degree of polyhydramnios.