Obstetric Outcomes Among Underage Mothers: Age-Stratified Analysis from a Romanian Hospital-Based Cohort

Background and Objectives: Adolescent pregnancy is traditionally associated with increased obstetric risk, particularly among very young adolescents. Romania continues to report one of the highest adolescent birth rates in the European Union, yet age-stratified clinical data on obstetric outcomes among minors remain limited. This study aimed to evaluate maternal and intrapartum outcomes among underage mothers (<18 years), stratified by age (<15, 15-16, and 17 years), and to identify predictors of adverse obstetric outcomes. Materials and Methods: We conducted a retrospective cohort study of all live births and stillbirths among mothers aged 12-17 years recorded between 2020 and 2024 at a secondary maternity hospital in Romania. Data were extracted from standardized obstetric and neonatal records. Primary outcomes included preterm birth (<37 weeks), cesarean delivery, and intrapartum complications. Group comparisons were performed using non-parametric tests and the χ² test. Multivariable logistic regression models were used to assess independent associations between maternal age and obstetric outcomes. Results: The cohort comprised 763 adolescent mothers aged 12-17 years. No significant differences were observed across age groups in gestational age at birth, preterm birth rate, fetal presentation, or mode of delivery. In multivariable analyses, younger maternal age was not independently associated with preterm birth (adjusted odds ratios [aORs] 0.87-1.21) or cesarean delivery (aORs 0.74-1.08). Obstetric factors, such as non-cephalic presentation and characteristics of membrane rupture, were the main predictors of adverse outcomes. Temporal analyses demonstrated stable outcome patterns across the study period, with no significant interaction between maternal age and year of delivery. Conclusions: In this tertiary-care cohort, very young maternal age (<15 years) was not associated with poorer obstetric outcomes compared with older adolescents. These findings suggest that standardized antenatal surveillance and intrapartum management may mitigate age-related obstetric risk among underage mothers. Further population-based studies are warranted to contextualize these results within broader healthcare access and social determinants of adolescent pregnancy. Cesarean section rates were high across all groups (~50%), with no significant differences by maternal age.