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Poster Session 1

(211) Age as an Independent Risk Factor for Cesarean Delivery

Thursday, January 30, 2025
10:30 AM – 12:30 PM  

    Submitting Author and Presenting Author(s)

  • Hillary Kroll, MD (she/her/hers)

    Resident Physician
    Kaiser Permanente Los Angeles Medical Center
    Kaiser Permanente Los Angeles Medical Center, California, United States

    • Coauthor(s)

  • EM

    Elena Martinez, MD, MPH

    OBGYN Faculty
    Kaiser Permanente Los Angeles
    Kaiser Permanente Los Angeles, California, United States

  • JL

    Jane C. Lin

    Kaiser Permanente Southern California
    Pasadena, California, United States

Objective: Few studies have examined the impact of maternal age on risk of C-section, especially at very advanced maternal ages. We sought to evaluate the association between maternal age at delivery and risk of C-section.

Study Design: This is a multicenter retrospective cohort study within a large integrated healthcare system. We examined all live births that occurred between 2012-2022. We excluded preterm deliveries, multifetal gestations, scheduled C-sections, patients with infrequent prenatal care, and patients not between the ages of 18-60 years old. We carried out a logistic regression analysis adjusted for race and ethnicity, parity, BMI, hypertension, pre-eclampsia, gestational diabetes, pre-gestational diabetes, fetal distress, fetal growth restriction, large for gestational age fetuses, macrosomia, APGAR scores, chorioamnionitis, meconium staining, and pregnancies resulting from assisted reproductive technology. We compared the risk of C-section in 5-year age intervals to a reference group of ages 25-34 using odds ratios.

Results: A total of 328,145 participants were included in the study. The rate of C-section in the reference group was 16.1%. The age range of 18-24 years old had a C-section rate of 13% with an odds ratio of 0.7 (95% CI [0.68, 0.72]), yielding a 30% decreased risk of C-section compared to the reference group. The rate of C-section in 35-39-year-olds was 20.7% with an odds ratio of 1.43 (95% CI [1.40, 1.47]) or a 43% increased risk of C-section. The rate of C-section in 40-44-year-olds was 25.7% with an odds ratio of 1.88 (95% CI [1.80, 1.96]) or an 88% increased risk of C-section. The rate of C-section in 45-49-year-olds was 33.5% with an odds ratio of 2.58 (95% CI [2.21, 3.01]) or a 158% increased risk of C-section. The rate of C-section in 50-60-year-olds was 50% with an odds ratio of 4.54 (95% CI [2.55, 8.06]) or a 354% increased risk of C-section.

Conclusion: After adjusting for other factors, age appears to be an independent risk factor for C-section. The risk of C-section increases with increasing age.