Normal Deepest Vertical Pocket in PPROM at 32 Weeks Gestation
A single deepest vertical pocket (maximum vertical pocket) of at least 2 cm is considered normal throughout gestation, including at 32 weeks with PPROM. 1
Standard Definition Across Gestational Ages
- The maximum vertical pocket (MVP) threshold of 2 cm vertical depth remains constant throughout pregnancy and does not change based on gestational age. 1
- This measurement represents the single maximal vertical pocket measured anywhere in the uterus, free of umbilical cord and fetal parts. 1
- Values below 2 cm define oligohydramnios, which is common in PPROM due to ongoing amniotic fluid leakage. 1
Clinical Context in PPROM
- In PPROM cases, oligohydramnios (deepest vertical pocket <2 cm) is frequently present and reflects the membrane rupture rather than necessarily indicating fetal compromise. 1
- The Society for Maternal-Fetal Medicine notes that oligohydramnios in the context of fetal growth restriction did not independently increase adverse outcomes, though this finding may not fully apply to PPROM where fluid loss is mechanical rather than placental. 1
- Later gestational age at PPROM and higher residual amniotic fluid volume are consistently associated with improved perinatal survival. 2
Measurement Technique
- The deepest vertical pocket should be measured in a plane perpendicular to the uterine contour, avoiding umbilical cord loops and fetal extremities. 1
- This single pocket measurement is preferred over the amniotic fluid index (AFI) for simplicity in fetal surveillance, though both methods have been used historically. 1
Important Clinical Pitfall
Do not assume that oligohydramnios in PPROM automatically indicates fetal compromise or need for immediate delivery at 32 weeks. The reduced fluid is expected with membrane rupture, and management decisions should be based on comprehensive fetal surveillance including fetal heart rate monitoring, signs of infection, and gestational age considerations rather than amniotic fluid volume alone. 1, 2