Recurrent preeclampsia: the effect of weight change between pregnancies.

OBJECTIVE: To estimate whether the risk of recurrent preeclampsia is affected by interpregnancy change in body mass index (BMI).

METHODS: We conducted a population-based cohort study using Missouri maternally linked birth certificates for 17,773 women whose first pregnancies were complicated by preeclampsia. The women were placed into three groups: those who decreased their BMIs, those who maintained their BMIs, and those who increased their BMIs between their first two pregnancies. The primary outcome was recurrent preeclampsia in the second pregnancy. Adjusted risk ratios and 95% confidence intervals were calculated using Poisson regression analysis.

RESULTS: The overall rate of recurrent preeclampsia in women who decreased their BMIs between pregnancies was 12.8% (risk ratio 0.70, confidence interval 0.60-0.81) compared with 14.8% if BMI was maintained and 18.5% in those who increased their BMIs (risk ratio 1.29, confidence interval 1.20-1.38). Within the normal weight, overweight, and obese weight categories, women who decreased BMI between pregnancies were less likely to experience recurrent preeclampsia. Women in all weight categories who increased their BMIs between pregnancies were more likely to experience recurrent preeclampsia.

CONCLUSION: Interpregnancy weight reduction decreases the risk of recurrent preeclampsia and should be encouraged in women who experience preeclampsia.

LEVEL OF EVIDENCE: II.