Earlier pregnancies in nulliparous women with current father and lower risks for preeclampsia and low-birth weight newborns.

New paternity has been related to placenta-associated complications in pregnancy. We evaluated whether a lack of earlier pregnancies or deliveries with a current father are associated with the pregnancy, prenatal, and early neonatal outcomes after controlling for the most common maternal confounders in prospective birth cohort study. An online questionnaire was used to survey 4459 pregnant women from the Kuopio Birth Cohort in their third trimester. The topics included their history of paternity in current and earlier pregnancies. Data were combined with prenatal, perinatal, and early neonatal information. A multivariable logistic regression analysis was performed to compare the possible associations between selected pregnancy and early neonatal outcomes with respect to paternal change. Pregnant women with changed partners had higher rates of smoking during pregnancy and hypertension before pregnancy. In the adjusted analysis, primigravidas and nulliparous multigravidas with different father had the highest risks for preeclampsia (adjusted odds ratios (aORs) 4.46 and 2.69, respectively), low birth weight (aORs 3.15 and 2.25), and smallness for gestational age (aORs 2.23 and 2.16) compared to the parous controls. Nulliparous women who had earlier pregnancies with the current father had less preeclampsia or gestational hypertension, as well as low birth weight (aOR 0.42, 95 % confidence interval (CI) 0.21-0.82 and aOR 0.26, 95 % CI 0.08-0.87, respectively) compared to other nulliparas. Among parous women, most of the pregnancy, obstetric, and early neonatal outcomes were similar in the adjusted analysis, regardless of new changes in paternity.