Risk factors for abdominal scar endometriosis after obstetric hysterotomies: a case-control study

Objective. to identify risk factors that are associated with the development of scar endometriosis after obstetric hysterotomies. The hypothesis is that early hysterotomy in pregnancy ( before 22nd week) is the main risk factor for the development of scar endometriosis. Methods. The authors conducted a case - control study between April 2000 and June 2003. A total of 117 women were selected, including 39 cases and 78 controls. Exposure and confounding variables were measured by a standardized questionnaire, which included sociodemographic characteristics, reproductive/physiologic history, past pathological history, history of obstetric surgeries, family history, and social history. The odds ratio ( OR) and its 95% confidence interval (CI) were calculated using bivariate analysis for each possible risk factor. These estimates were obtained by multivariate analysis using unconditional logistic regression. Tests were made to assess the fit of the final model. Results. In the multivariate analysis, positive associations were observed between scar endometriosis and hysterotomy type ( early versus late: OR = 42.99; CI 8.77 - 210.81), amount of the menstrual blood flow ( heavy versus light/normal: OR = 11.97; CI 2.35 - 60.82), and alcoholic consumption ( yes versus no: OR = 5.31; CI 1.22 - 23.11). Negative association was observed between scar endometriosis and parity ( OR = 0.61; CI 0.31 - 1.23), however it was not statistically significant ( p > 0.05). Conclusions. Early hysterotomy in pregnancy is the main risk factor for scar endometriosis. Increased menstrual flow and alcohol consumption are also risk factors, while high parity may be a protecting factor.