The impact of chronic hypertension and pregestational diabetes on pregnancy outcomes.

OBJECTIVE: The objective of the study was to examine the impact of chronic hypertension and pregestational diabetes on pregnancy outcomes. STUDY DESIGN: This was a retrospective cohort study of 532,088 women undergoing singleton births in California in 2006. Women were categorized into chronic hypertension, pregestational diabetes, both, or neither. Pregnancy outcomes were compared using the χ(2) test and multivariable logistic regression to control for potential confounders. RESULTS: We identified differences in perinatal outcomes between the groups. The rate of preterm birth in women with both conditions was 35.5% versus 25.5% in women with chronic hypertension versus 19.4% in women with pregestational diabetes (P < .001). The rate of small for gestational age was 18.2% in women with both versus 18.3% in women with chronic hypertension versus 9.7% in women with pregestational diabetes (P < .001). CONCLUSION: The impact of having both chronic hypertension and pregestational diabetes in pregnancy varies, depending on the outcome examined. Although some had an additive effect (eg, stillbirth), others did not (eg, preeclampsia).