Grand multiparity and obstetric outcomes in a contemporary cohort: the role of increasing 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: Multi-center retrospective cohort of patients with parity ≥5 who delivered a singleton gestation in New York City from 2011-2019. Outcomes included postpartum hemorrhage, preterm delivery, hypertensive disorders of pregnancy, shoulder dystocia, birthweight >4000 grams and <2500 grams, and 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 pre-specified adverse outcomes. Odds of postpartum hemorrhage increased with history (aOR 2.65 [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 (OR 5.89 [3.22, 10.79]) and birth weight >4000g (aOR 9.94 [6.32, 15.65]). Birthweight >4000 grams was associated with maternal obesity (aOR 2.92 [2.22, 3.84]). Birthweight <2500 grams 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 95% CI [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.