What is the definition of polyhydramnios according to the American College of Obstetricians and Gynecologists (ACOG)?

From the Guidelines

Polyhydramnios is defined as an MVP > 8 cm or an AFI > 25 cm or >95th percentile for gestational age, according to the American College of Obstetricians and Gynecologists (ACOG) guidelines. This definition is based on the most recent and highest quality study available, which highlights the importance of accurate assessment of amniotic fluid volume in pregnancy outcomes 1.

Key Points to Consider

• The definition of polyhydramnios is crucial in identifying pregnancies at risk of adverse outcomes, such as perinatal mortality and stillbirth 1.
• The use of MVP or AFI in assessing amniotic fluid volume is essential, with MVP potentially performing better than AFI in some cases 1.
• Polyhydramnios is associated with increased risks of adverse fetal outcomes, including perinatal mortality and stillbirth, with an odds ratio of 5.8 (95% CI, 3.68-9.11) compared to normal amniotic fluid 1.

Management and Treatment

• Management of polyhydramnios typically involves increased monitoring of both mother and fetus, with treatment depending on the underlying cause and severity.
• In cases where maternal discomfort is significant, amnioreduction (removal of excess fluid) may be considered.
• Proper diagnosis and management of polyhydramnios are crucial for optimal pregnancy outcomes, given the increased risks of preterm labor, placental abruption, and umbilical cord prolapse associated with this condition.

From the Research

Definition of Polyhydramnios

The definition of polyhydramnios, according to the Society for Maternal-Fetal Medicine Consult Series #46, is an abnormal increase in the volume of amniotic fluid, which can be identified by a deepest vertical pocket (DVP) of ≥8 cm or an amniotic fluid index (AFI) of ≥24 cm 2.

Diagnostic Criteria

The diagnostic criteria for polyhydramnios include:

• A deepest vertical pocket (DVP) of ≥8 cm 2, 3
• An amniotic fluid index (AFI) of ≥24 cm 2
• A DVP of ≥10 cm may also be used to define moderate-severe polyhydramnios, corresponding to an AFI of ≥30 cm 3

Causes and Associations

Polyhydramnios can be associated with various causes, including:

• Maternal diabetes mellitus 2, 4
• Fetal anomalies 2
• Congenital infection 2
• Alloimmunization 2
• Pregnancies with diabetes have increased rates of oligohydramnios and polyhydramnios, as well as increased gestational age-specific amniotic fluid volumes between 28 and 36 weeks 4