Fetomaternal Outcome Among Antenatal Attendees With Advanced Maternal Age: A Cohort Study

Background Advanced maternal age (AMA) has become increasingly prevalent as women postpone childbearing due to social, cultural, and economic reasons. Previous studies have linked AMA to a higher risk of adverse maternal and fetal outcomes, but regional data from Oman remain limited. Objective This study aimed to evaluate the association between AMA and pregnancy outcomes in women attending antenatal visits at Musannah Polyclinic and AR-Rustaq General Hospital. Methodology This observational comparative cohort study was conducted at Musannah Polyclinic, Sultanate of Oman, over 12 months beginning in July 2024. A total of 646 pregnant women were enrolled, comprising 323 women aged ≥40 years (AMA group) and 323 women <35 years (control group). Participants were recruited using non-probability convenience sampling. Data collection included demographic variables, maternal comorbidities, pregnancy complications, and fetal outcomes. Laboratory and imaging assessments were performed according to Ministry of Health protocols. Statistical analysis was conducted using SPSS version 26, with t-tests and chi-square tests applied for group comparisons, and logistic regression performed to identify independent predictors of adverse outcomes. Results The mean age in the AMA group was 42.8 ± 2.1 years versus 28.6 ± 3.5 years in controls (p < 0.001). AMA women had significantly lower spontaneous vaginal delivery rates (52/323; 16.1% vs. 149/323; 46.1%, p < 0.001) and higher preterm delivery rates (14/323; 4.3% vs. 5/323; 1.5%, p = 0.03). Gestational diabetes was significantly higher in AMA women (156/323; 48.3% vs. 47/323; 14.6%, p < 0.001), as were hypertensive disorders (38/323; 11.8% vs. 9/323; 2.8%, p < 0.001) and thyroid disorders (38/323; 11.8% vs. 11/323; 3.4%, p < 0.001). Fetal complications were also increased, including miscarriage (17/323; 5.3% vs. 4/323; 1.2%, p = 0.004) and NICU admissions (11/323; 3.4% vs. 3/323; 0.9%, p = 0.04). Logistic regression confirmed AMA as an independent predictor of gestational diabetes, hypertensive disorders, cesarean delivery, miscarriage, NICU admission, and thyroid disorders. Conclusion AMA is strongly associated with adverse maternal and fetal outcomes, underscoring the need for targeted antenatal monitoring, early screening, and specialized counseling in this high-risk group.