Factors associated with mode of delivery in large-for-gestational-age fetuses: a retrospective cohort study.

Background: Large-for-gestational-age (LGA) fetuses are often associated with increased maternal and neonatal morbidity. Although suspicion of LGA can prompt closer surveillance and interventions such as labor induction, the actual impact on delivery outcomes and complications remains controversial.

Purpose: To assess maternal and fetal factors associated with the mode of delivery in pregnancies with LGA fetuses.

Basic procedures: Retrospective, single-center study (2018-2021) including term, singleton pregnancies with birthweight ≥ 90th percentile (AUDIPOG). Exclusion criteria were prior cesarean, multiples, preterm birth, non-cephalic presentation, planned cesarean, maternal request, or incomplete records. Primary outcome was mode of delivery. Multiple logistic regression was used.

Main findings: A total of 211 women met inclusion criteria. The rate of operative delivery (cesarean or instrumental vaginal birth) was 32.2% (68/211). In multiple logistic regression, nulliparity (OR 8.1, 95% CI 3.2-20.5, p < 0.001), induction of labor (OR 2.6, 95% CI 1.1-6.3, p = 0.035), greater gestational weight gain (OR 1.07 per kg, 95% CI 1.01-1.14, p = 0.021), and prenatal suspicion of macrosomia (EFW > 90th percentile at growth or third-trimester ultrasound, OR 2.9, 95% CI 1.2-7.1, p = 0.019) were independently associated with an increased risk of non-spontaneous birth. Maternal age, diabetes, and a history of LGA were not significantly associated after adjustment. Neonatal outcomes were favorable, with only one case of umbilical arterial pH < 7.00 (0.5%) and no severe traumatic complications.

Conclusions: In LGA pregnancies, nulliparity and suspected macrosomia were associated with higher rates of medical intervention, whereas induction and prior vaginal delivery favored spontaneous birth. Neonatal weight did not differ between delivery modes. These findings underscore the complexity of managing suspected LGA fetuses and the need for prospective multicenter studies to refine risk stratification.