Risk of Selected Fetal Adverse Pregnancy Outcomes at Advanced Maternal Age: A Retrospective Cohort Study in Debre Markos Referral Hospital, Northwest Ethiopia.

Introduction: Pregnancy at an advanced maternal age is defined as pregnancy at 35 years or older. Today, women postpone pregnancy due to different socioeconomic and personal reasons. However, there was limited evidence on fetal adverse outcomes' association with pregnancy at an advanced maternal age in Ethiopia and particularly in the study area. This study was aimed at assessing the effect of pregnancy at an advanced age on selected neonatal adverse pregnancy outcomes in Debre Markos Referral Hospital, Ethiopia, 2019.

Methods: Institution-based retrospective cohort study was conducted on 303 exposed (35 years and older) and 604 nonexposed (20-34 years old) immediate postpartum women who delivered at Debre Markos Referral Hospital after 28 weeks of gestation. All exposed women who fulfilled the inclusion criteria were sampled, and systematic random sampling was employed for those in the nonexposed group. The data were collected from 1st of July to 30th of December, 2019, by face-to-face interview and extraction from maternal chart using a structured questionnaire and data extraction checklist, respectively. Binary logistic regression (bivariate and multivariable) model was fitted, and wealth index was analyzed by principal component analysis. Adjusted relative risk with respect to 95% confidence interval was employed for the strength and directions of association between advanced maternal age and selected adverse pregnancy outcomes, respectively. P-value of <0.05 was used to declare statistical significance.

Results: The incidence of adverse neonatal outcomes including stillbirth, preterm birth, and low birth weight in the advanced maternal age group was 13.2%, 19.8%, and 16.5%, respectively. The incidence of stillbirth, preterm birth, and low birth weight in the nonexposed group was 3.1%, 8.4%, and 12.4%, respectively. The advanced maternal age group had three times the risk of stillbirth compared with the nonexposed group (ARR = 3.14 95% CI (1.30-7.00)). The advanced maternal age group had 2.66 times the risk of delivering preterm fetus (ARR = 2.66 95% CI (1.81-3.77)) compared with the younger counterparts. Low birth weight was not significantly associated with pregnancy at an advanced maternal age.

Conclusion: Fetal adverse outcomes including stillbirth and preterm birth were significantly associated with pregnancy at an advanced maternal age.