Timing of elective repeat cesarean delivery and maternal and neonatal outcomes

Objective To explore the optimal timing of termination of pregnancy,we analyzed the different gestational age in repeat cesarean delivery and maternal and neonatal outcomes.Methods This was a retrospective study.The information of cesarean sections was collected from maternal obstetric records in the electronic medical recording system of the First Affiliated Hospital of Chongqing Medical University from June 1,2011 to June 30,2013,and women with intrauterine viable singleton pregnancies delivered after 37 weeks of gestation without prenatal complications were selected.They were divided into five groups with different gestational weeks.Maternal general information,perioperative outcome and rate of neonatal adverse event were analyzed with one way ANOVA analysis and Chi-square test.Results A total of 579 cases of elective repeat cesarean at term were performed.The ratios of cesarean section prior to 39 and 39-39+6 weeks of gestation were 64.6％ (374/579) and 29.0％ (168/579),respectively.No fetal,neonatal or maternal death occurred.There were no statistically significant differences in the termination of pregnancy at 37-37+6 weeks,38 38+6 weeks,39-39+6 weeks,40 weeks and ≥ 41 weeks between the two time intervals for cesarean section (P＞0.05).There were statistically significant differences in the length of hospitalization [(4.9±3.0),(4.3 ± 1.3),(4.3 ± 1.0),(4.5± 1.2) and (4.0±0.7) d,respectively; F=2.849,P＜0.05].No significant difference was observed in the maternal BMI,placental membrane residue,maternal perioperative bleeding,premature rupture of membrane (PROM),intensive care unit (ICU) admission and uterine resection (P＞0.05).There were statistically significant differences among the five groups in neonatal weight [(3 082.9±479.2),(3 318.1 ±390.8),(3 415.7±431.1),(3 630.5±475.2) and (3 334.0±242.5) g,F=13.798] and length [(48.8± 1.5),(49.3± 1.5),(49.6± 1.5),(50.0± 1.5) and (47.8±3.9) cm,F=7.460; both P＜0.05].One min and 5 min Apgar scores also showed statistically significant differences [1 min:(9.7±0.7),(9.8±0.6),(9.8±0.4),(9.7±0.5) and (8.8±2.7) ; F=4.432; 5 min:(9.9±0.3),(10.0±0.3),(10.0±0.2),(10.0±0.2) and (9.2± 1.8),F=9.625; all P＜0.05].The overall rates of neonatal adverse events,including the admission to neonatal intensive care units (NICU),the rates of cardiopulmonary resuscitation or ventilator therapy,asphyxiation,as well as the length of stay in NICU ≥ 5 d among the five groups also showed statistically significant differences [overall:5.4％ (5/93),1.8％ (5/281),0.6％ (1/168),0.0％ (0/32) and 2/5,x2=16.812;NICU:3.2％ (3/93),1.1％ (3/281),0.0％ (0/168),0.0％ (0/32) and 1/5; x2=1 1.294; cardiopulmonary resuscitation or ventilator therapy:2.2％ (2/93),0.7％ (2/281),0.0％ (0/168),0.0％(0/32) and 1/5,x2=10.584; asphyxiation:1.1％ (1/93),0.7％ (2/281),0.0％ (0/168),0.0％ (0/32) and 1/5,x2=9.637; NICU ≥ 5 d:3.2％ (3/93),1.1％ (3/281),0.0％ (0/168),0.0％ (0/32) and 1/5,x2=1 1.294; P＜0.05].The risks of neonatal adverse outcomes in delivery at 37-38+6 weeks were:OR=1.1(95％CI:1.0-2.1) at 37 37+6 weeks,OR=1.3 (95％CI:0.9-1.9) at 38-38+6 weeks,compared with delivery at 39-39+6 weeks.Conclnsions The percentage of repeat cesarean delivery prior to 39 weeks of gestation is high in our hospital,early termination of pregnancy would not reduce the maternal perioperative adverse outcome,but may increase the risk of neonatal adverse events.Taking into account the maternal benefit,we suggest 39 39+6 weeks of gestation as the best time of elective repeat cesarean in order to reduce the risk of neonatal adverse events. Key words: Cesarean section, repeat;  Pregnancy outcome