Induced and Spontaneous Abortion and Risk of Uterine Fibroids

The relationship between abortion and uterine fibroids has received little attention. The aim of the present study was to explore the association between number of induced and spontaneous abortions and the risk of uterine fibroids in middle-aged and older Chinese women.

A total of 14,595 retired female employees from the Dongfeng-Tongji cohort study were included in our analysis. Information on induced and spontaneous abortions was collected by trained interviewers through face-to-face interviews. Diagnosis of uterine fibroids was based on ultrasound or self-reported physician diagnosis of uterine fibroids. Logistic regression models were used to explore the associations between number of induced and spontaneous abortions and the risk of uterine fibroids.

The prevalence of uterine fibroids was 15.1% among all participants. Higher number of induced abortions was associated with an increased risk of uterine fibroids (1 induced abortion: odds ratios [ORs] = 1.32, 95% confidence interval [CI] 1.18-1.48; 2 induced abortions: OR = 1.45, 95% CI 1.28-1.64; and ≥3 induced abortions: OR = 1.62, 95% CI 1.39-1.90). Compared with women without induced abortion, ORs for women with 1, 2, and ≥3 were 1.17 (95% CI 1.03-1.32), 1.21 (95% CI 1.06-1.39), and 1.36 (95% CI 1.15-1.61), respectively, after adjustment for potential confounders. No association was observed between the number of spontaneous abortions and the risk of uterine fibroids.

The findings of this study showed that induced abortion may be an independent risk factor for uterine fibroids in middle-aged and older Chinese women.