Association of placenta praevia with repeat cesarean section in Omdurman Maternity Hospital, Sudan 2010- 2012

Background: Several risk factors for placenta praevia exist, including previous cesarean section(C/S). This association has been investigated long time ago, however in this hospital there is no documented evidence. This study was done to assess the risk of placenta praevia based on number of previous cesarean sections.Methods: A hospital-based study, at Omdurman maternity hospital- OMH during; January 2010-December 2012. Deliveries in OMH were reviewed by trained registrars. Patients diagnosed prenatally or during delivery as placenta praevia were included. All women operated were followed till discharge from hospital.Results: Total number of deliveries during the study period is 94758.Of them 68415 (72.2%) delivered vaginally and 26343 (27.8%) by C/S.Of the latter 10643 (40.4%) underwent elective and 15700 (59.6%) emergency CS.448 (0.5%) were diagnosed as placenta praevia. Placenta praevia was more common in patients with scarred uterus being found a 250 out of 9853 CS (2.5%). Its frequency increased with the number of uterine scars: one scar; (1.7%), (RR = 1.45, CI= 1.12-1.88), 2-4 scars (2.8%), (RR = 2.32, CI= 1.87-2.87) & five or more scars; (12.7%), (RR = 10.54, CI= 7.34-15.13). Nineteen patients (7.6%) had adherent placenta, (RR = 42.41, CI =5.69-315.83), 68(15.2%) had history of dilatation and curettage (D&C) or evacuation,(RR = 1.5, CI = 1.18-1.94), 37 (8.3%) had previous history of placenta praevia, (RR= 8.30, CI = 6.17- 11.19). Threematernal deaths were encountered (0.7%).Conclusion: The frequency of placenta praevia in this study increased with increasing number of previous C/S, and was associated with adverse feto-maternal outcome. This study provides a reason to reduce primary C/S and encouraging vaginal birth after C/S (VBAC).Key words: Placenta praevia. Repeated cesarean section. Sudan