Change in paternity: a risk factor for preeclampsia in multiparous women?

Background: Preeclampsia is often thought of as being a disease of first pregnancies. The incidence of preeclampsia in subsequent pregnancies, after a previous normal pregnancy is lower. However, it has been reported that this beneficial effect of multiparity is lost with a change in paternity. The aim of this study was to assess the impact of change in paternity on the incidence of preeclampsia in Dutch multiparous pregnant women.
Methods: 364 Multiparous patients with hypertension (diastolic blood pressure > or = 100 mmHg) were identified in the obstetric database of the Academic Hospital Vrije Universiteit Amsterdam for the period 1989-1996. The diagnosis in their obstetrical history (Preeclampsia, HELLP-syndrome, chronic hypertension) was defined in a pragmatic way in view of the retrospective nature of the study. The control group consisted of 281 multiparous women from a midwife clinic, with normotensive pregnancies in the same period. Patients and controls were asked, by telephone, if the index pregnancy was from the same partner as the previous pregnancy and what the sex of the newborns had been in each pregnancy. Fisher's Exact test was used for statistical analysis and P < 0.05 was considered significant.
Results: The final study group consisted of 333 multiparous patients with hypertension. The control group consisted of 182 multiparous women without hypertension. The prevalence of new paternity was significantly higher (P < 0.0001) both for preeclamptic and HELLP patients in comparison with the controls, with an odds ratio of 8.6 (95%CI: 3.1-23.5) and 10.9 (95%CI: 3.7-32.3), respectively.
Conclusion: This study confirms that change of partner raises the risk for preeclampsia in subsequent pregnancies. Immune maladaptation on the fetal maternal interface could be an underlying mechanism. Multiparous women with a new partner should be approached as being primigravid women.