1166 Short interpregnancy interval and risk of severe maternal morbidity in the United States

Abstract

Short interpregnancy interval (IPI) increases risk of preterm birth and other adverse pregnancy outcomes. This study aims to investigate whether short IPI, a modifiable risk factor, increases risk of severe maternal morbidity, which is an antecedent to maternal mortality. Retrospective population-based cohort study of all US live births using birth certificate records, 2012-2016. Study population was limited to multiparous mothers with data on IPI since the most recent prior birth. Exposure variables were short IPI defined as < 6 and <12 months. Severe maternal morbidity, a marker for maternal mortality risk, was defined as maternal ICU admission, blood transfusion, uterine rupture or unplanned hysterectomy during delivery hospitalization. Logistic regression estimated risk of SMM with short IPI, after adjustment for maternal race, age, obesity, no prenatal care, and Medicaid. There were 19,844,580 live births in the US during the study period, of which 10,714,861 were in multiparous women with data on IPI. The frequency of short IPI was 5.7% and 16.7% for births at <6 and <12 months, respectively. The frequency of composite severe maternal morbidity was 44 per 10,000 live births, and among women with the shortest IPI of <6 months was 52 per 10,000. After adjusting for the coexisting risks for SMM, short IPI <6 months was associated with 22% increased risk of SMM, adjRR 1.22 (95% CI 1.12,1.33) and short IPI <12 months had no significant increase in risk of SMM, adjRR 1.04 (CI 0.99, 1.10). Pregnancies that occur < 6 months following a recent birth increase the risk of severe maternal mortality in the US. Access to immediate postpartum highly effective contraception may help to prevent unintended pregnancy in the postpartum period. This could help to minimize very short IPIs in the US in effort to minimize the occurrence of serious maternal adverse events that lead to maternal mortality.View Large Image Figure ViewerDownload Hi-res image Download (PPT)