Does an amniotic fluid index of ≤5 cm necessitate delivery in high-risk pregnancies?: A case-control study

OBJECTIVE: This study was undertaken to determine whether women with high-risk pregnancies and an amniotic fluid index of less than or equal to 5 cm require labor induction to prevent adverse perinatal outcomes. STUDY DESIGN: All women at high risk at greater than or equal to 34 weeks' gestation with an amniotic fluid index of less than or equal to 5 cm were admitted to the hospital for labor induction. Each woman was compared with the next patient at high risk seen with an amniotic fluid index of >5 cm and the same pregnancy complication. Case patients were also matched with control subjects for maternal race, age, parity, and gestational age. RESULTS: Prospectively, 79 women at high risk with an amniotic fluid index of less than or equal to 5 cm were compared with 79 control subjects. There were no statistically significant differences between the 2 groups in the risks of thick meconium (P=.29), variable decelerations (moderate P=.27, severe P=.37), amnioinfusion (P=.37), cesarean delivery for fetal distress (P=.4), and umbilical artery pH <7.10 (P=.29). CONCLUSION: High-risk pregnancies with an amniotic fluid index of less than or equal to 5 cm appear to carry intrapartum complication rates similar to those of similar high-risk pregnancies with an amniotic fluid index of >5.