Perinatal outcomes in grand multiparous women stratified by parity- A large multicenter study

To assess the effect of each additional delivery among grand multiparous (GMP) women on maternal and neonatal outcomes.

A multi-center retrospective cohort study that examined maternal and neonatal outcomes of GMP women (parity 5-10, analyzed separately for each parity level) compared to a reference group of multiparous women (parity 2-4). The study population included grand multiparous women with singleton gestation who delivered in one of four university-affiliated obstetrical centers in a single geographic area, between 2003 and 2021. We excluded nulliparous, those with parity > 10 (due to small sample sizes), women with previous cesarean deliveries (CDs), multifetal gestations, and out-of-hospital deliveries. The primary outcome of this study was postpartum hemorrhage (PPH, estimated blood loss exceeding 1000 ml, and/or requiring blood product transfusion, and/or a hemoglobin drop > 3 g/Dl). Secondary outcomes included unplanned cesarean deliveries, preterm delivery, along with other adverse maternal and neonatal outcomes. Univariate analysis was followed by multivariable logistic regression.

During the study period, 251,786 deliveries of 120,793 patients met the inclusion and exclusion criteria. Of those, 173,113 (69%) were of parity 2-4 (reference group), 27,894 (11%) were of parity five, 19,146 (8%) were of parity six, 13,115 (5%) were of parity seven, 8903 (4%) were of parity eight, 5802 (2%) were of parity nine and 3813 (2%) were of parity ten. GMP women exhibited significantly higher rates of PPH starting from parity eight. The adjusted odds ratios (aOR) were 1.19 (95 % CI: 1.06-1.34) for parity 8, 1.17 (95 % CI: 1.01-1.36) for parity 9, and 1.39 (95 % CI: 1.18-1.65) for parity 10. Additionally, they showed elevated rates of several maternal and neonatal outcomes, including placental abruption, large-for-gestational age (LGA) neonates, neonatal hypoglycemia, and neonatal seizures. Conversely, they exhibited decreased risk for other adverse maternal outcomes, including preterm deliveries, unplanned cesarean deliveries (CDs), vacuum-assisted delivery, and third- or fourth-degree perineal tears and small-for-gestational age (SGA) neonates. The associations with neonatal hypoglycemia, and neonatal seizure were correlated with the number of deliveries in a dose-dependent manner, demonstrating that each additional delivery was associated with an additional, significant impact on obstetrical complications.

Our study demonstrates that parity 8-10 is associated with a significantly increased risk of PPH. Parity level > 5 correlated with increased odds of placental abruption, LGA neonates, neonatal hypoglycemia, and neonatal seizures. However, GMP women also demonstrated a reduced likelihood of certain adverse maternal outcomes, including unplanned cesarean, preterm deliveries, vacuum-assisted deliveries, SGA neonates, and severe perineal tears. These findings highlight the importance of tailored obstetrical care for GMP women to mitigate the elevated risks associated with higher parity.