The Major Contributors to the Cesarean Section Risk in Nulliparous Women Aged 35 Years and Older

Objective: To assess the association between advanced maternal age (AMA) and cesarean section (CS) risk in nulliparous pregnant women aged 35 years and older and examine potential confounders to enhance guidance for pregnant women and healthcare providers. Study Design: This retrospective cohort study of singleton, nulliparous pregnant women with a fetus in the cephalic presentation admitted for delivery was carried out from 1 January 2022 to 31 December 2022. Maternal demographics, medical history, delivery records, and neonatal outcomes were collected from electronic medical records. Univariate and multiple logistic regression analyses identified variables independently associated with CS in AMA cases. Results: The study included an AMA group (≥35 years, n=52) and a control group (<35 years, n=487). The CS rate was significantly higher in the AMA group (67.3%) compared to the control group (26.1%, p<0.001). Multiple logistic regression revealed that assisted reproductive technology (ART) pregnancies (OR: 39.0), presence of additional maternal disease or pregnancy complication (OR: 5.34), and fetal heart rate (FHR) category III (OR: 3.34) were significantly associated with increased CS risk in AMA women. Conclusion: The risk of CS is significantly elevated in nulliparous women aged 35 and older, particularly among those who conceived through ART, presented with additional maternal diseases, or exhibited FHR category III. These findings provide essential insights for obstetricians to inform AMA patients on CS risks, aiding decision-making.