Background Repeat abortion is a significant and growing public health problem in Scotland and is associated with poor maternal and perinatal outcomes in future pregnancies. Despite a number of publications in this area, there is a lack of consensus regarding the risk factors for repeat abortion. We aimed to identify the determinants of repeat abortion using a systematic review of quantitative studies.

Methods A bibliographic search strategy was developed based on the review question – what are the determinant factors for repeat abortions? Papers were identified from searches in MEDLINE; EMBASE; Cochrane Central Register of Controlled Trials and Cochrane Database for Systematic Reviews with no date or language restrictions. Hand searches and bibliographies of reviews were also completed. Studies were included if they examined the determinants of woman with repeat abortions compared to woman with less or no abortions. Two independent reviewers screened titles, abstracts and full text papers using pre-defined inclusion/exclusion criteria. Data extraction, quality assessment and a narrative synthesis was completed on the included papers.

Results From the 3933 studies screened, 67 studies met the inclusion criteria; of these studies 46 were available in full texts. The included studies lacked homogeneity as there was a large variation in study methodology and the definition of repeat abortion. From these studies a number of themes became apparent such as socio-demographic, sexual behaviour, obstetric history and psychosocial factors. There are a number of associated factors with repeat abortion such as increased age, parity, marital status, use of contraception at the time of conception and previous history of abuse or adverse life events. Many studies show that either barrier or oral contraceptive methods were used at the time of conception; these women were also less likely to use long acting reversible contraception before or after an abortion.

Conclusion Consistent determinants for repeat abortions include contraception use, domestic abuse and adverse life events. With a lack of methodological standardisation among studies it is difficult to generalise the determinants that have a greater association with repeat abortion. Future research needs to propose a definition that can be used uniformly across the discipline and examine whether repeat abortions are a result of user or method failures of contraception.

Keywords repeat abortion