Parity-Related Differences in Neonatal Outcomes Among Adolescent Mothers: A Retrospective Cohort Study.

Background/Objectives: Adolescent pregnancy is associated with an increased risk of adverse neonatal outcomes, including low birth weight, preterm birth, and impaired neonatal adaptation. While maternal age is a well-established determinant, the independent role of parity in this population remains uncertain. This study aimed to assess the association between parity and neonatal outcomes in adolescent mothers. Methods: We conducted a retrospective cohort study including 751 singleton live-birth deliveries to adolescent mothers aged <18 years at a Romanian secondary-care hospital. The unit of analysis was the delivery episode recorded in the institutional birth registry. Mothers were classified according to parity at the time of the index delivery as primiparous or multiparous. Neonatal outcomes included low birth weight (<2500 g), preterm birth (<37 weeks), Apgar score < 7 at 5 min, and a composite adverse neonatal outcome. Multivariable logistic regression models were used to evaluate the association between parity and neonatal outcomes, adjusting for maternal age (<15 vs. ≥15 years), gestational age, and mode of delivery, as appropriate. Results: A total of 751 singleton live-birth delivery episodes were included; 609 (81.1%) occurred in primiparous adolescents and 142 (18.9%) in multiparous adolescents. Parity was not significantly associated with preterm birth (aOR 0.86, 95% CI 0.48-1.56, p = 0.622), Apgar score < 7 at 5 min, or the composite adverse neonatal outcome. Maternal age < 15 years and gestational age were independently associated with Apgar score < 7 at 5 min. Multiparity was associated with lower odds of low birth weight (aOR 0.40, 95% CI 0.17-0.92, p = 0.031). Conclusions: Parity was not independently associated with most neonatal outcomes in adolescent pregnancies. Multiparity was associated with lower odds of low birth weight, but this finding should be interpreted cautiously because residual confounding cannot be excluded.