Pregnancies complicated by abruption result in increased frequency of
perinatal death and decreased fetal size and gestational duration, yet the
extent of placental separation and its effect on these adverse outcomes is
To assess the contribution of placental abruption and extent of placental
separation to stillbirth, preterm delivery, and fetal growth restriction.
Hospital-based, retrospective cohort study.
Mount Sinai Hospital, New York City, NY.
A total of 53,371 pregnancies occurring in 40,789 women who were delivered
of singleton births between 1986 and 1996.
Main Outcome Measures
Risks and relative risks for stillbirth (>20 weeks), preterm delivery
(<37 weeks), and fetal growth restriction (birth weight below 10th percentile
for gestational age) in relation to abruption.
The incidence of abruption was 1% (n = 530). Abruption was associated
with an 8.9-fold (95% confidence interval [CI], 6.0-13.0) adjusted relative
risk (aRR) of stillbirth. Preterm birth proportions among women with and without
abruption were 39.6% and 9.1%, respectively, yielding an aRR of 3.9 (95% CI,
3.5-4.4). In the abruption group, 14.3% of neonates were growth restricted,
compared with 8.1% among all other births (aRR, 2.0; 95% CI, 1.5-2.4). Extent
of placental separation had a profound effect on stillbirth (aRR for 75% separation,
31.5; 95% CI, 17.0-58.4), although evident only among those with at least
50% separation. However, the risk of preterm delivery was substantially increased
even for mild abruptions (aRR for 25% separation, 5.5; 95% CI, 4.2-7.3).
In this cohort, placental abruption had a profound impact on stillbirth,
preterm delivery, and fetal growth restriction. The risk of stillbirth was
dramatically increased for severe placental separation, but preterm delivery
was common even among women with lesser degrees of placental separation.