ANTIBIOTICS AT THE TIME OF INDUCED-ABORTION - THE CASE FOR UNIVERSAL PROPHYLAXIS BASED ON A METAANALYSIS

Objective: To determine the efficacy of periabortal antibiotics in pre venting postabortal upper genital tract infection using data from publ ished trials. Data Sources: We performed a literature search of all st udies published from January 1966 to September 1, 1994, using MEDLINE, and we manually searched bibliographies of published articles. MEDLIN E search terms included: abortion, infection, prophylaxis, antibiotics , pelvic inflammatory disease (PID), and suction curettage. Methods of Study Selection: Randomized, controlled trials comparing antibiotics with placebo in women undergoing suction curettage abortion before 16 weeks' gestation were identified. Tabulation, Integration, and Results : Data were extracted independently by two reviewers, one of whom was blinded to journal, year of publication, authors, and institution. Dat a from 12 studies were combined using meta-analytic techniques based o n a fixed-effects model. The overall summary relative risk (RR) estima te for developing postabortal upper genital tract infection in women r eceiving antibiotic therapy compared with those receiving placebo was 0.58 (95% confidence interval [CI] 0.47-0.71). Of high-risk women, tho se with a history of PID had a summary RR estimate of 0.56 [95% CI 0.3 7-0.84); women with a positive chlamydia culture at abortion had a sum mary RR estimate of 0.38 (95% CI 0.15-0.92). Of low-risk women, those with no reported history of PID had a summary RR estimate of 0.65 (95% CI 0.47-0.90); in women with a negative chlamydia culture, the summar y RR estimate was 0.63 (95% CI 0.42-0.97). The lowest summary RR estim ate was among women drawn from populations with a low incidence (5-6%) of postabortal infection (summary RR estimate 0.22, 95% CI 0.11-0.42) . The overall 42% decreased risk of infection in women given periabort al antibiotics is similar to the risk reduction demonstrable when only studies published before 1985 are combined (summary RR estimate 0.63, 95% CI 0.44-0.89). Conclusion: Our meta-analysis revealed a substanti al protective effect of antibiotics in all subgroups of women undergoi ng therapeutic abortion, even women in low-risk groups. No more placeb o-controlled trials should be performed, because women assigned to pla cebo are exposed to preventable risk. Routine use of periabortal antib iotics in the United States may prevent up to half of all cases of pos tabortal infections.