- ACTUAL NUMBER IS AN INDEPENDENT PREDICTOR FOR INTRAOPERATIVE MATERNAL MORBIDITY IN SUBSEQUENT PREGNANCIES AFTER PRIMARY CESAREAN SECTION OFFER EREZ, LENA NOVACK, VERED KLEITMAN-MEIR, DORON DUKLER, MOSHE MAZOR, Soroka University Medical Center, BeerSheva, Israel, Ben Gurion University of the Negev Faculty of Helth sciences, Epidemiology, Beer-Sheva, Israel, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, OB/GYN, BeerSheva, Israel OBJECTIVE: To investigate the association between the number of subsequent deliveries after primary cesarean section (CS), the rate of successful vaginal deliveries and intraoperative maternal morbidity during repeated CS. STUDY DESIGN: A retrospective population based cohort study was designed. Patients with primary CS comprised the study population (n = 6233), women in the study group were followed up to maximum 4th consecutive delivery after their primary CS. A survival analysis model (Cox regression) was performed to investigate the association between the number of repeated CS, their proportion out of the number of subsequent deliveries after the primary CS and intraoperative maternal morbidity. Intraoperative morbidity was defined as primary outcome and included scar dehiscence, uterine rupture, cesarean hysterectomy, trauma to adjacent organs and transfusion of blood products. RESULTS: During the study period there were 11,338 deliveries of them 5,859 VBAC deliveries, and 5479 recurrent CS. The prevalence of repeated CS in subsequent deliveries was found to be an independent risk factor for dehiscence of cesarean scar, uterine rupture, cesarean hysterectomy, trauma to adjacent organs during the operation and blood transfusion ((Hazard Ratio (HR) 14.27, p=0.005; HR-5.12 p=0.005; HR-3.38 p!0.02; HR-7.73 p=0.004; HR2.5 p=0.02, respectively). Maternal parity before the primary CS was an independent risk factor for cesarean hysterectomy (HR-1.33 p!0.001). Elective CS had an overall protective effect against intraoperative complications (HR-0.74 p=0.027), this effect could not be attributed to a specific complication. CONCLUSION: 1) The higher intraoperative morbidity is positively related to the percentage of repeated cesarean deliveries rather than their actual number representing the protective effect of repeated successful VBAC; 2) the increased risk for cesarean hysterectomy among multiparous patients can be attributed to intraoperative medical judgment; and 3) elective repeated cesarean delivery has a protective effect against intraoperative complications.