Obesity increases the risk of severe preeclampsia in pregnancy

Objective: To evaluate the impact of maternal obesity on the development of severe preeclampsia in pregnancy.

Methods: Retrospective cohort analysis of n = 13.083 deliveries between January 2000 -December 2011 at the Department of Obstetrics and Gynecology of University Hospital Schleswig-Holstein, Campus Lübeck. Severe preeclampsia was defined as blood pressure ≥180/110mmHG and proteinuria > 3 g/l. Results were analyzed dividing the patients (pts.) into 2 groups; 1: BMI (Body mass index) 18,5 – 24,9; 2: BMI > 25. Subgroups were built: (I) BMI 25 – 29,9, (II) BMI 30 – 34,9, (III) BMI 35 – 39,9, (IV) BMI > 40. Exclusion criteria: incomplete data, multiple pregnancy, BMI < 18,5, height < 1,50 m. Main outcome parameter: rate of severe preeclampsia, gestational diabetes mellitus (GDM), mode of delivery.

Results: n =11.227 pts. met the inclusion criteria and were divided into 2 groups: (1) n =7.271 pts.; (2) n =3.955 pts.. Basic maternal characteristics were equal in all groups.

A significant difference in the rate of severe preeclampsia in favour of group 2 was observed (0,5% vs. 0,3%, p < 0,001, OR 2,9, 95% CI 1,7 – 5,1). Subgroup analyses showed similar results and varied from subgroup I 0,6% (15/2431) to subgroup IV 1,5% (3/195).

GDM occurred more frequently in group 2 than in group 1 (p < 0,001). Obesity was associated to significantly higher secondary c-section rates (group 1: 14,7% vs. group 2: 19,6%, p < 0,001, OR 1,3, 95% CI 1,2 – 1,5) and lower spontaneous delivery rates (group 1: 64,4% vs. group 2: 57,8%, p < 0,001, OR: 0,9, 95% CI 0,9 – 0,9).

Conclusion: Obesity increases the risk of severe preeclampsia. Accordingly, obese patients need to be given birth surgically more often.