Paternal age and adverse pregnancy outcomes: a spline analysis from the nulliparous pregnancy outcomes study: monitoring mothers-to-be study

Objectives Extremes of maternal age are associated with an increased risk of adverse pregnancy outcomes (APOs). Less is known about the independent effects of extremes of paternal age on reproductive risk.Methods We conducted a secondary analysis using data from the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be (nuMoM2b) using restricted cubic spline logistic regression to examine the non-linear association between paternal age and APOs and adverse fetal/neonatal outcomes.Results After adjusting for maternal health and sociodemographic and paternal sociodemographic confounders, we found no evidence of overall association (χ2 = 3.88, p = 0.143) or non-linearity (χ2 = 1.72, p = 0.189) between paternal age and composite APOs and adverse fetal/neonatal outcomes (Table 1). Additionally, after adjustment we did not find any statistical significance when examining separate composite APO outcomes (overall: χ2 = 3.02, p = 0.221; non-linearity: χ2 = 2.68, p = 0.101) or composite adverse fetal/neonatal outcomes (overall: χ2 = 1.73, p = 0.421; non-linearity: χ2 = 0.14, p = 0.706). Among adjusted individual outcomes, only gestational hypertension showed statistical significance for both overall association (χ2 = 6.72, p = 0.035) and evidence of non-linearity (χ2 = 4.12, p = 0.042).Conclusions While our findings do not support a strong independent association between paternal age and composite APOs and adverse fetal/neonatal outcomes, the non-linear association with gestational hypertension may warrant further study with sufficient paternal age representation and paternal health factors.