Incidence,obstetric risk factors and pregnancy outcome of preterm placental abruption: a retrospective analysis

Objective: To determine obstetric risk factors for the occurrence of preterm placental abruption and to investigate its subsequent perinatal outcome. Study design: A retrospective comparison of all singleton preterm deliveries complicated with placental abruption, between the years 1990-1998, to all singleton preterm deliveries without placental abruption, in the Soroka University Medical Center. Results: Placental abruption complicated 300 (5.1%) of all preterm deliveries (n = 5934). A back-step multivariable analysis found the following factors to be independently correlated with the occurrence of preterm placental abruption: grandmultiparity (more than five deliveries), early gestational age, severe pregnancy-induced hypertension, previous second-trimester bleeding and non-vertex presentation. These pregnancies had a significantly lower rate of preterm premature rupture of membranes than preterm pregnancies without placental abruption. Pregnancies complicated with preterm placental abruption had significantly higher rates of cord prolapse, non-reassuring fetal heart rate patterns, congenital malformations, Cesarean deliveries, perinatal mortality, Apgar scores lower than 7 at 5 min, postpartum anemia and delayed discharge from the hospital than did preterm deliveries without placental abruption. In order to assess whether the increased risk for perinatal mortality was due to the placental abruption, or due to its significant association with other risk factors, a multivariable analysis was constructed with perinatal mortality as the outcome variable. Placental abruption (OR 3.0, 95% CI 2.1-4.1) as well as cord prolapse, previous perinatal death, low birth weight and congenital malformations were found to be independent risk factors for perinatal mortality. Conclusion: Preterm placental abruption is an unpredictable severe complication associated with significant perinatal morbidity and mortality. Factors found to be independently associated with placental abruption were grandmultiparity, severe pregnancy-induced hypertension, malpresentation, earlier gestational age and a history of second-trimester vaginal bleeding.