Risk factors for hypoxic-ischemic encephalopathy or neonatal death in placental abruption

To identify risk factors for moderate or severe hypoxic-ischemic encephalopathy (HIE), or neonatal death in clinical placental abruption.

A nested case-control study within a cohort of singleton pregnancies complicated by placental abruption with a live born infant at two academic reference centers in France, from 2006 to 2019. Cases were patients who gave birth to an infant with moderate or severe HIE or death within 28 days (HIE/death group), and controls were patients whose infant did not have any of these outcomes (no-HIE group). Independent risk factors were identified by logistic regression. Binary decision tree discriminant (CART) analysis was performed to define high-risk subgroups of HIE or death.

Among 152 patients, the infants of 44 (29%) had HIE or death. Out-of-hospital placental abruption and fetal bradycardia at admission were more frequent in cases than in controls: 39 (89%) vs 61 (56%), p < .01 and 24 (59%) vs 19 (18%), p < .01, respectively. In multivariate analysis, out-of-hospital placental abruption (aOR, 7.05; 95% CI, 1.94-25.66) and bradycardia at admission (aOR, 8.60; 95% CI, 2.51-29.42) were independently associated with an increased risk of HIE or death. The combination of out-of-hospital placental abruption and bradycardia was the highest risk situation associated with HIE or death (67%). The decision-to-delivery interval was 15 [12-20] minutes among cases.

Out-of-hospital placental abruption combined with bradycardia at admission was associated with a major risk of moderate or severe HIE or death. An optimal decision-to-delivery interval does not guarantee the absence of an adverse neonatal outcome.