[Impact of the number of cesarean deliveries on adverse pregnancy outcomes of cesarean section in a single-center cohort study].

Objective: To investigate the impact of the number of cesarean deliveries on adverse maternal and neonatal outcomes. Methods: A retrospective analysis was conducted on 11 904 singleton pregnant women who underwent cesarean delivery at the Third Affiliated Hospital of Guangzhou Medical University from January 1st, 2019 to December 31st, 2023. The women were grouped according to the number of cesarean deliveries: those undergoing their first cesarean delivery (1CD group, 7 231 cases), those undergoing their second cesarean delivery (2CD group, 3 749 cases), those undergoing their third cesarean delivery (3CD group, 841 cases), and those undergoing their fourth or more cesarean deliveries (4CD group, 83 cases). Differences in clinical characteristics, related surgical procedures, and adverse maternal and neonatal outcomes among the groups were compared. Binary logistic regression analysis was used to assess the impact of the number of cesarean deliveries on related surgical procedures and adverse maternal and neonatal outcomes. Results: (1) During the 5-year period, the total number of women undergoing cesarean delivery in our hospital showed a slight downward trend, while the proportion of women undergoing three or more cesarean deliveries increased. (2) Compared with women undergoing their first cesarean delivery, women in each repeat cesarean delivery group were older, had higher proportions of advanced maternal age and pre-pregnancy body mass index, and had more pregnancies, deliveries, and induced abortions; the incidence of placenta previa, placental implantation, antepartum hemorrhage, gestational hyperglycemia, and failed trial of labor requiring conversion to surgery was higher, while the incidence of premature rupture of membranes was lower; the proportions of ureteral stent placement, adhesiolysis of the pelvic and abdominal cavities, uterine rupture, uterine reconstruction, uterine artery ligation, hysterectomy, postpartum hemorrhage, and postoperative intestinal obstruction were higher, and the amount of postpartum hemorrhage was greater; the gestational age at delivery of neonates was earlier, but the rates of preterm birth at 28-31⁺⁶ and 32-33⁺⁶ weeks of gestation were lower; the differences were statistically significant (P<0.05) for all comparisons. (3) The number of cesarean deliveries was not an independent risk factor for the dose-dependent occurrence of placenta previa (aOR=0.99, 95%CI: 0.98-1.01; P=0.261). In women without placenta previa, the number of cesarean deliveries was not a risk factor for placental implantation (aOR=1.12, 95%CI: 0.90-1.39; P=0.320). However, in women with placenta previa, the number of cesarean deliveries was a risk factor for placental implantation (aOR=4.01, 95%CI: 3.08-5.22; P<0.001). In the overall population, the number of cesarean deliveries was a risk factor for ureteral stent placement, adhesiolysis of the pelvic and abdominal cavities, bladder rupture repair, uterine rupture, uterine reconstruction, uterine artery ligation, hysterectomy, postpartum hemorrhage, and preterm birth (all P<0.05). However, the number of cesarean deliveries was not a risk factor for postoperative intestinal obstruction, admission to the intensive care unit, neonatal asphyxia, admission to the neonatal intensive care unit, or neonatal death (all P<0.05). Conclusions: The number of cesarean deliveries could lead to adverse maternal and neonatal outcomes, but the relationship is not simply dose-dependent. It is speculated that the occurrence of severe adverse maternal and neonatal outcomes is more closely related to maternal complications and comorbidities, as well as whether multidisciplinary comprehensive management was received.