Is prior uterine surgery a risk factor for adenomyosis?

OBJECTIVE: The objective of our study was to assess whether prior uterine surgery is a risk factor for adenomyosis. METHODS: Medical records of women who had a hysterectomy for benign conditions between January of 1995 and June of 2002 were reviewed. Women with and without adenomyosis were compared with respect to history of prior uterine surgery, such as cesarean delivery, myomectomy, endometrial ablation, dilation and evacuation, and dilation and curettage. RESULTS: Of 873 completed records available, 412 patients (47.1%) had adenomyosis. Mean age and race distribution were similar between the 2 groups. The group with adenomyosis had significantly higher gravidity (P < .001) and parity (P = .004), but smaller uterine size (P < .001) and uterine weight (P < .001). Univariable analysis for each aforementioned specific surgical procedure did not indicate a significant difference between women with and without adenomyosis. However, history of any prior uterine surgery increased the risk of adenomyosis (48.8% and 41.0%, odds ratio 1.37, 95% confidence interval 1.05-1.79) on univariable analysis. This association remained significant when all of the factors were combined in a multivariable logistic regression model. CONCLUSION: In this study, we found a significantly increased risk of adenomyosis with prior uterine surgery. The absence of significant association with any specific surgical procedure is possibly the result of a smaller number of subjects in each individual group. LEVEL OF EVIDENCE: II-3.