Effectiveness of timing strategies for delivery of individuals with placenta previa and accreta.

OBJECTIVE: To compare strategies for the timing of delivery in individuals with placenta previa and ultrasonographic evidence of placenta accreta, and to determine the optimal gestational age at which to deliver individuals.
METHODS: A decision tree was designed comparing nine strategies for delivery timing in an individual with placenta previa and ultrasonographic evidence of placenta accreta. The strategies ranged from a scheduled delivery at 34, 35, 36, 37, 38, or 39 weeks of gestation to a scheduled delivery at 36, 37, or 38 weeks of gestation only after amniocentesis confirmation of fetal lung maturity. Outcomes factored into the model included maternal intensive care unit admission, perinatal mortality, infant mortality, respiratory distress syndrome, mental retardation, and cerebral palsy.
RESULTS: A scheduled delivery at 34 weeks of gestation was the preferred strategy and resulted in the highest quality-adjusted life years under the base case assumptions. Strategies awaiting confirmation of fetal lung maturity failed to result in better outcome than strategies that delivered at the corresponding gestational age without amniocentesis. After sensitivity analyses, delivery at 37 weeks of gestation without amniocentesis was the preferred strategy in limited situations, and delivery at 39 weeks of gestation was the preferred strategy only in unlikely situations.
CONCLUSION: This decision analysis suggests the preferred strategy for timing of delivery in individuals with ultrasonographic evidence of placenta previa and placenta accreta under a variety of circumstances is delivery at 34 weeks of gestation. At any given gestational age, incorporating amniocentesis for verification of fetal lung maturity does not assist in the management of such individuals. LEVEL OF EVIDENCE: III.