Changing paternity and the risk of preeclampsia/eclampsia in the subsequent pregnancy

To determine whether changing paternity affects the risk of preeclampsia or eclampsia in the subsequent pregnancy and whether the effect depends on a woman's history of preeclampsia/eclampsia with her previous partner, a coho rt study was conducted based on 140,147 women with two consecutive births d uring 1989-1991 identified through linking of annual California birth certi ficate data. Among women without preeclampsia/eclampsia in the first birth, changing partners resulted in a 30% increase in the risk of preeclampsia/e clampsia in the subsequent pregnancy compared with those who did not change partners (95% confidence interval: 1.1, 1.6). On the other hand, among wom en with preeclampsia/eclampsia in the first birth, changing partners result ed in a 30% reduction in the risk of preeclampsia/eclampsia in the subseque nt pregnancy (95% confidence interval: 0.4, 1.2). The difference of the eff ect of changing paternity on the risk of preeclampsia/eclampsia between wom en with and those without a history of this condition was significant (p < 0.05 for the interaction term). The above estimates were adjusted for poten tial confounders. These findings suggest that the effect of changing patern ity depends on the history of preeclampsia/eclampsia with the previous part ner and support the hypothesis that parental human leukocyte antigen sharin g may play a role in the etiology of preeclampsia/eclampsia.