Predictors of Short Interpregnancy Interval in Adolescent Patients [ID 1317]

INTRODUCTION: Short interpregnancy interval (SII), defined as less than 18 months from delivery to subsequent conception, is associated with adverse maternal and fetal outcomes in the subsequent pregnancy, especially among adolescents. This study aims to evaluate the incidence of SII among adolescent patients and to identify associated risk factors. METHODS: A retrospective cohort study of adolescent patients delivering at a single health system from May 1, 2013, to April 30, 2023, was conducted. Patients who delivered after 20 weeks and were 10–17 years old for the index and subsequent pregnancy were included. Sociodemographic and clinical variables were abstracted from the electronic medical record. Primary outcome was incidence of SII in adolescence. Secondary analysis compared patients with SII to those without a second pregnancy before age 18. Bivariate analyses and regression models were used to identify factors associated with SII. RESULTS: Of 455 patients, 252 (55.4%) had a recurrent adolescent pregnancy. Of these, 62 (24.6%) had SII. On bivariate analysis, no significant associations were observed between race/ethnicity, mode of delivery, or age at first pregnancy and SII. Short interpregnancy interval was positively associated with shoulder dystocia ( P =.008) and current education level, with higher rates of SII among those in GED programs and middle school ( P =.05). Transfusion ( P =.05) and long-acting reversible contraceptive (LARC) use ( P <.001) were negatively correlated with SII. In adjusted regression analysis, LARC use (adjusted relative risk, 0.18; 95% CI, 0.08, 0.44) remained significantly protective against SII. CONCLUSIONS/IMPLICATIONS: Rates of recurrent adolescent pregnancy and SII are high. Long-acting reversible contraceptive placement was identified as the primary protective factor against SII for adolescent patients. Further research is needed to assess barriers to LARC utilization in postpartum adolescents.