Do Hypertensive Disorders of Pregnancy and Abnormal Placentation Mediate the Association between Advanced Maternal Age and Adverse Perinatal Outcomes?

A tertiary-hospital-based retrospective study (2011-2019) was conducted to determine the mediating role of hypertensive disorders of pregnancy and abnormal placentations between advanced maternal age and adverse neonatal outcomes.

Data from a tertiary-hospital-based retrospective study (n= 23051) was used and conducted regression-based mediation analysis to assess the mediating role of hypertensive disorders of pregnancy and abnormal placentation between the advanced maternal age and adverse neonatal outcomes.

After adjusting for confounding factors, the indirect effect of advanced maternal age on preterm births, perinatal mortality, and low birth weight mediated by hypertensive disorders of pregnancy was [aOR 4.95 (95% CI: 4.05, 5.85)], [aOR 2.82 (95% CI: 1.78, 3.86)], and [aOR 5.90 (95% CI: 4.93, 6.87)], respectively. The indirect effect of advanced maternal age on preterm births and low birth weight mediated by abnormal placentation was [aOR 6.83 (95% CI: 5.70, 7.97)] and [aOR 4.18 (95% CI: 3.26, 5.11)].  About, 23%, 37%, and 17% of the effect of advanced maternal age on preterm births, perinatal mortality, and low birth weight was mediated by hypertensive disorders of pregnancy, respectively. Furthermore, abnormal placentation mediates the association between advanced maternal age and preterm births by 18% and low birth weight by 23%. 

Hypertensive disorders of pregnancy and abnormal placentation partially mediate the association between advanced maternal age and adverse neonatal outcomes.