CHANGE IN PATERNITY - A RISK FACTOR FOR PREECLAMPSIA IN MULTIPARAS

Preeclampsia, a hypertensive disorder of pregnancy, is hypothesized to be a maternal immunologic response to foreign fetal antigen derived f rom the father's sperm. This response may be reduced by prolonged expo sure to father's antigen, such as through a prior pregnancy, which may explain why multiparas are typically at lower risk for preeclampsia t han nulliparas. Since multiparas with new partners are presented with a new set of paternal antigen, we hypothesize that they would have the same elevated risk for preeclampsia and gestational hyper tension as nulliparas, compared with multiparas with no change in partner. We stu died 5,048 nulliparas and 5,800 multiparas, 573 of whom had new partne rs, selected from the Child Health and Development Studies cohort (Oak land, CA, 1959-1961). Preeclampsia was diagnosed in 3.2% of nulliparas , 3.0% of multiparas with changed paternity, and 1.9% of multiparas wi th no change. Compared with multiparas with no change, the adjusted od ds ratio for preeclampsia among nulliparas was 2.5 [95% confidence int erval (CI) = 1.8-3.5]; among multiparas with new partners, the adjuste d odds ratio for preeclampsia was 1.4 (95% CI = 0.8-2.4). There was a similar pattern of results for gestational hypertension. The adjusted attributable risk of preeclampsia in multiparas associated with a chan ge in paternity was 29%. Although these findings in part support the i mmunologic theory of preeclampsia sia, they also suggest that a subseq uent pregnancy with any partner is associated with a reduced risk for preeclampsia.