Frequency and risk factors for repeat abortions after surgical compared with medical termination of pregnancy.

OBJECTIVE

To compare the frequency and risk factors for repeat abortions after surgical compared with medical termination of pregnancy.

METHODS

Frequency of and risk factors for repeat abortions after medical (performed with mifepristone alone, or with a combination of mifepristone and misoprostol or other prostaglandins) compared with surgical (dilation and curettage, or vacuum aspiration) termination of pregnancy were studied using Finnish national health registries. The cohort consisted of 40,360 women undergoing termination of pregnancy between 2000 and 2005 (19,841 medical and 20,519 surgical abortions) with duration of gestation of 63 days or less. Univariable and multivariable association models were used in connection with various factors associated with repeat abortion. The mean (+/-standard deviation) follow-up times were 3.0 (+/-1.5) and 4.3 (+/-1.9) years, respectively.

RESULTS

Women choosing surgical and medical abortion differed subtly, but significantly in several respects. The total number of repeat terminations was 37.9 per follow-up year per 1,000 after surgical termination of pregnancy and 40.4 after medical termination of pregnancy (P=.01). However, medical termination of pregnancy was not linked to an increased risk of another abortion when compared with surgical methods (hazard ratio [HR] 0.98, 95% confidence interval [CI] 0.93-1.04). In multivariable analysis, the risk factors for repeat abortion were parity (HR 1.99, 95% CI 1.85-2.14), previous abortion(s) (HR 1.70, 95% CI 1.60-1.82), low socioeconomic status (HR 1.22, 95% CI 1.06-1.39), and being unmarried but cohabiting (HR 1.14, 95% CI 1.03-1.25) or single (HR 1.25, 95% CI 1.15-1.36). The risk of repeat termination of pregnancy decreased with age, among women living in rural areas, and when intrauterine devices or sterilization were planned for future contraception.

CONCLUSION

The risk of repeat abortion is associated with various sociodemographic characteristics. The method of abortion used is not a risk factor for repeat termination of pregnancy.

LEVEL OF EVIDENCE: II.