The influence of maternal cigarette smoking on placental pathology in pregnancies complicated by abruption.

OBJECTIVE The purpose of this study was to evaluate the effect of maternal cigarette smoking on placental histology in women with abruption. STUDY DESIGN Data were derived from the New Jersey-Placental Abruption Study (NJ-PAS)--an ongoing, case-control study, conducted since August 2002 in 2 large hospitals in NJ. Abruption cases were identified based on a clinical diagnosis. Histologic evaluations were performed by 2 perinatal pathologists who were blinded to the abruption status. Maternal smoking during pregnancy was determined based on patient's self-report. Among abruption cases, histologic findings were compared between smokers and nonsmokers, and the association expressed as odds ratio (OR) with 95% confidence interval (CI). All analyses were adjusted for potential confounders. RESULTS A total of 189 abruption cases were available for analysis, of which 10.6% (n = 20) were smokers. Intervillous thrombus was more common in women who smoked (20%) than in nonsmokers (3.0%) (OR, 17.5; 95% CI, 3.1-99.4). However, placental infarcts were seen less frequently among smokers than nonsmokers (10.0% vs 32.5%; OR, 0.2; 95% CI, 0.1-0.8). CONCLUSION These findings suggest that different pathologic mechanisms may be responsible for the histologic findings between smokers and nonsmokers diagnosed with placental abruption.