Chronic abruption-oligohydramnios sequence

To determine outcome in patients with chronic abruption.

A retrospective review was performed of all patients delivering at a tertiary medical center during a 54-month period. All patients with a diagnosis of placental abruption with oligohydramnios or ruptured membranes were included. Chronic abruption-oligohydramnios sequence (CAOS) was defined by the following criteria: (1) clinically significant vaginal bleeding in the absence of placenta previa or other identifiable source of bleeding, (2) amniotic fluid volume initially documented as normal, and (3) oligohydramnios (amniotic fluid index < or = 5) eventually developing without concurrent evidence of ruptured membranes.

Twenty-four patients with CAOS were identified. Fourteen had first evidence of abruption at < 20 weeks' gestational age. A clot was identified between the chorion and uterus in 18/24. The mean gestational age at the first bleeding episode was 19.4 +/- 5.5 (SD) weeks, with the mean gestational age at delivery 28.1 +/- 4.5 weeks. Preterm premature membrane rupture occurred in 15/24. In these 15 there was a mean of 11.5 +/- days between the diagnosis of oligohydramnios and of ruptured membranes. Patients whose first blood occurred at < 20 weeks' gestation delivered at a gestational age of 26.1 +/- 3.9 weeks versus 33.0 +/- 5.3 weeks for the control group.

CAOS can occur in pregnancies complicated by abruptio placentae. If it develops, the mean gestational age at delivery is 28 weeks.