A history of placental dysfunction and risk of placental abruption

In a population-based historic cohort study we assessed the possible association of fetal growth retardation, preterm birth and pregnancy-induced hypertension in the immediately preceding pregnancy with placental abruption in the current pregnancy, which would suggest a shared aetiological factor. We also assessed whether chronic hypertension, diabetes mellitus and a history of Caesarean section are associated with placental abruption. Preterm birth and small-for-gestational-age (SGA) in the immediately preceding delivery were associated with an increased risk of placental abruption with unadjusted odds ratios (ORs) of 2.1 [95% CI=1.9, 2.4] and 1.6 [95% CI=1.5, 1.8] respectively. Women with a history of an SGA preterm birth in the immediately preceding delivery and an appropriate-for-gestational-age infant in the current had an adjusted OR of 3.2 [95% CI=2.3, 4.5]. The adjusted odds ratio of placental abruption in women who had pregnancy-induced hypertension in the previous pregnancy, but not in the current, was 1.4 [95% CI=1.2, 1.7]. Women who delivered a preterm or SGA infant in the previous delivery and had chronic hypertension or diabetes mellitus in the current had adjusted ORs of 2.3-5.7 and 2.5-6.0 respectively. Caesarean section in the previous delivery increased the risk of placental abruption by 40%. These results suggest that pregnancy-induced hypertension, intrauterine growth retardation, preterm delivery and placental abruption share an aetiological factor or represent different clinical expressions of recurring placental dysfunction. Chronic hypertension and diabetes mellitus may cause or aggravate such dysfunction thus causing placental abruption. A history of Caesarean section is associated with an increased risk of placental abruption.