Grand Multiparity and Obstetric Outcomes in a Contemporary Cohort: the Role of Parity

Objective Evidence is inconsistent regarding grand multiparity and its association with adverse obstetric outcomes. Few large American cohorts of grand multiparas have been studied. We assessed if increasing parity among grand multiparas is associated with increased odds of adverse perinatal outcomes.Study Design Multicenter retrospective cohort of patients with parity >= 5 who delivered a singleton gestation in New York City from 2011 to 2019. Outcomes included postpartum hemorrhage, preterm delivery, hypertensive disorders of pregnancy, shoulder dystocia, birth weight > 4,000 and <2,500 g, and neonatal intensive care unit (NICU) admission. Parity was analyzed continuously, and multivariate analysis determined if increasing parity and other obstetric variables were associated with each adverse outcome.Results There were 2,496 patients who met inclusion criteria. Increasing parity among grand multiparas was not associated with any of the prespecified adverse outcomes. Odds of postpartum hemorrhage increased with history (adjusted odds ratio [aOR]: 2.65, 95% confidence interval [1.83, 3.84]) and current cesarean delivery (aOR: 4.59 [3.40, 6.18]). Preterm delivery was associated with history (aOR: 12.36 [8.70-17.58]) and non-White race (aOR: 1.90 [1.27, 2.84]). Odds of shoulder dystocia increased with history (aOR: 5.89 [3.22, 10.79]) and birth weight > 4,000 g (aOR: 9.94 [6.32, 15.65]). Birth weight > 4,000 g was associated with maternal obesity (aOR: 2.92 [2.22, 3.84]). Birth weight < 2,500 g was associated with advanced maternal age (aOR: 1.69 [1.15, 2.48]), chronic hypertension (aOR: 2.45 [1.32, 4.53]), and non-White race (aOR: 2.47 [1.66, 3.68]). Odds of hypertensive disorders of pregnancy increased with advanced maternal age (aOR: 1.79 [1.25, 2.56]), history (aOR: 10.09 [6.77-15.04]), and non-White race (aOR: 2.79 [1.95, 4.00]). NICU admission was associated with advanced maternal age (aOR: 1.47 [1.06, 2.02]) and non-White race (aOR: 2.57 [1.84, 3.58]).Conclusion Among grand multiparous patients, the risk factor for adverse maternal, obstetric, and neonatal outcomes appears to be occurrence of those adverse events in a prior pregnancy and not increasing parity itself. Key Points Increasing parity is not associated with adverse obstetric outcomes among grand multiparas. Prior adverse pregnancy outcome is a risk factor for the outcome among grand multiparas. Advanced maternal age is associated with adverse obstetric outcomes among grand multiparas.