Sickle cell disease is associated with multiple adverse pregnancy outcomes. It is unknown if sickle cell trait (SCT) confers increased risk of similar adverse outcomes. Our objective was to compare differences in adverse pregnancy outcomes, specifically hypertensive disorders (PIH) and fetal growth restriction, between women with SCT and those with normal hemoglobin profiles in a modern population.METHODS:
We conducted a retrospective cohort study of women who delivered between 2006 and 2013 in the Kaiser Permanente Northern California (KPNC). We identified patients from their hemoglobin electrophoretic profiles. Our primary outcomes were PIH (gestational hypertension, preeclampsia, and eclampsia) and small-for-gestational-age infants (SGA). We compared categorical variables using Chi-square tests and continuous variables using t test and nonparametric tests. Multivariable logistic regression modeling examined associations between maternal characteristics and risk of the primary outcomes.RESULTS:
Of the eligible 34,713 women, 965 had HbAS and 33,748 had HbAA. From bivariate analysis, we observed that women with SCT were more likely to have PIH (16.8% vs 13.0%, P<.001) and SGA (8.2% vs 6.2%, P=.01). In multivariable analysis, after controlling for maternal age, race/ethnicity, and preexisting hypertension, SCT was neither an independent predictor of PIH nor of SGA.CONCLUSION:
SCT does not appear to be associated with increased risk of adverse pregnancy outcomes including PIH and SGA. The rigorous methodology used to identify the study population, by excluding potentially confounding hemoglobinopathies other than HbAS, provides more robust data about SCT and perinatal outcomes than has been published previously. This information is useful for counseling and managing pregnant women with SCT.