Recurrence of preeclampsia: effects of gestational age at delivery of the first pregnancy, body mass index, paternity, and interval between births.

OBJECTIVES: The purpose of this study was to establish estimates for recurrence risk of preeclampsia based on gestational age at delivery of the first pregnancy complicated by preeclampsia and to determine whether interbirth interval, paternity, and body mass index (BMI) modify that risk in women with prior preeclampsia.

STUDY DESIGN: A population-based, cohort study was conducted using data from Missouri maternally linked birth certificates. The cohort included women who had 2 singleton births between 1989 and 1997: 6157 women with preeclampsia and 97,703 women without preeclampsia at the time of their first deliveries. Data were analyzed using the Poisson regression.

RESULTS: At the time of their second delivery, 14.7% women with prior preeclampsia developed recurrent preeclampsia. The risk of recurrent preeclampsia is inversely related to gestational age at the first delivery: 38.6% for 28 weeks' gestation or earlier, 29.1% for 29-32 weeks, 21.9% for 33-36 weeks, and 12.9% for 37 weeks or more. The recurrent preeclampsia risk was fairly constant if both births occurred within 7 years. Obese and overweight women had higher risks of recurrent preeclampsia (19.3% and 14.2%), compared with women with normal BMI (11.2%). The recurrence risk did not differ according to paternity status.

CONCLUSION: The risk of preeclampsia recurrence increases with earlier gestational age at the first delivery complicated by preeclampsia and with increasing maternal BMI.