Identifying possible risk factors for cesarean scar pregnancy based on a retrospective study of 291 cases.

Aim: Cesarean scar pregnancy (CSP) is a rare but life-threatening type of ectopic pregnancy. This study's aim is to investigate the clinical characteristics and possible risk factors for cesarean scar pregnancy.

Methods: A clinically randomized, unpaired and retrospective case-control study was implemented. A study group of 291 CSP patients and a control group of 317 full-term pregnant women with a history of cesarean section (CS) were recruited in our hospital from May 2013 to October 2018. Their demographic characteristics and medical and obstetric history were collected.

Results: Only symptoms suggestive of an impending abortion, such as vaginal bleeding with or without abdominal pain, were identified as the clinical characteristics of CSP. Maternal age older than 35 years, gravidity higher than 3 (especially gravidity higher than 5), more than two induced abortions (especially more than five abortions), an interval of less than 5 years (especially less than 2 years) between the current pregnancy and the last CS, history of CS performed in a rural hospital, history of induced abortions after CS and retroposition of the uterus were possible independent risk factors for CSP.

Conclusion: CSP is a result of a combination of multiple factors associated with CS. There are no unique early clinical features of CSP. As a unique type of ectopic pregnancy, early diagnosis, early termination and early clearance should be the treatment principles. Further research is needed to evaluate the relationship between the cesarean scar defect and CSP in the future.