378 Age, parity and interval from previous delivery – influence on perinatal outcome

Abstract

To investigate the effect of parity and interpregnancy interval (IPI) on perinatal outcomes in advanced maternal age parturients (>40 years). A population-based retrospective cohort study of all women older than 40 years old, who had a singleton live birth after 24 weeks in the US in 2017 (http://data.nber.org/data/vital-statistics-natality-data.html). Women were categorized to three groups by parity and interval from last delivery: primiparas, multiparas with IPI<5 years, and multiparas with IPI>5 years. Primary outcome was composite neonatal outcome (preterm delivery <34 weeks, birthweight <2000 grams, neonatal seizures, neonatal intensive care unit admission, Apgar score less than 7 at 5 minutes or neonatal assisted ventilation for more than 6 hours). Secondary outcome was maternal composite (uterine rupture, unplanned hysterectomy, maternal intensive care unit admission or maternal blood transfusion) and other adverse perinatal outcomes. Univariate analysis followed by multivariate analysis was used to compare between groups. During 2017, 3,864,754 deliveries were recorded into the database. Following exclusion, 109,564 elderly gravidas entered analysis. Of them, 24,769(22.6%) were nulliparas, 39,933(36.4%) were multiparas with IPI< 5 years and 44,862(40.9%) were multiparas with IPI>5 years. Composite neonatal outcome was higher in nulliparas and in multiparas with IPI > 5 years, in comparison to multiparas with IPI lower than 5 years (16% vs. 13% vs. 10%, respectively, p<0.05). Nulliparas had higher rates of hypertensive disorders, induction of labor, cesarean deliveries and postpartum blood transfusions. However, maternal composite outcome was similar between groups (Table 1). In the multivariable analysis, relative to nulliparas, only multiparity with IPI<5 years had a protective effect against the composite neonatal outcome (aOR 0.97, 95% CI 0.95-0.99, p<0.001), Table 2. Among elderly gravidas, multiparity with IPI≤5 years has a significant protective effect against adverse neonatal outcomes. Multiparity with IPI>5 years is no longer protective.View Large Image Figure ViewerDownload Hi-res image Download (PPT)