Pre-eclampsia in the second pregnancy: Does previous outcome matter?

Objective: To assess the effect of initial pregnancy outcome and gestational age on the risk of pre-eclampsia in the second pregnancy.
Study design: We conducted an observational study using routinely collected data from the Aberdeen Maternity and Neonatal Databank between 1986 and 2006. Cases were women who developed pre-eclampsia in their second pregnancy and controls were normotensive in their second pregnancy. Crude and adjusted odds ratios were produced for each of the risk factors using logistic regression.

Results: Inter-pregnancy intervals of 6 years or more were associated with increased incidence of pre-eclampsia (19.4% vs. 14.7%). A change of partner had a protective effect while an increase in BMI increased the risk of pre-eclampsia. A history of pre-eclampsia was associated with 5 times higher risk {adjusted O.R. 5.12 (95% C.I. 4.42-6.48)} of pre-eclampsia in the second pregnancy. Compared to a term delivery, a previous second trimester pregnancy loss was associated with a 4 times higher risk {adjusted O.R. 4.22 (95% C.I. 2.54-7.03)} of pre-eclampsia in the next pregnancy. Previous very preterm and preterm births were associated with adjusted odds ratios of 2.32 (95% C.I. 1.62-3.32) and 1.62 (95% C.I. 1.46-1.72) respectively. The risk of pre-eclampsia was no higher in women with a previous history of fetal death after 20 weeks than those with a previous live birth, after adjusting for pre-eclampsia in the first pregnancy.

Conclusion: Only initial deliveries beyond 37 weeks, irrespective of outcome, were protective against pre-eclampsia in the second pregnancy.