Purpose: Although studies suggest that antibiotics around the time of early surgical abortion reduce infection rates, most studies were performed at centers where infection was diagnosed in >5% of women receiving antibiotics. No major publications from North America have reported infections rates higher that 1%. Additionally, long-term outcomes are not generally evaluated in trials of antibiotic use at abortion. We performed a cost-effectiveness analysis to examine the benefits and consequences of using antibiotic prophylaxis in a range of high to low risk settings.

Methods: A Markov model of antibiotic side-effects, infection and infection sequelae (ectopic, chronic pain, & infertility) was developed. Three options were considered: no antibiotics, prophylactic antibiotics (pre-abortion single-dose), and treatment-dose antibiotics (post-abortion multiple-dose). The base case assumed a 2% infection rate and a 25% side-effect rate. Four models were run using either 20-year-old or 30-year-old women who do or do not desire children in the future. One-way, two-way, and Monte Carlo sensitivity analyses were performed. A $50,000 per QALY cost-effectiveness threshold was used.

Results: For a 20 or 30-year old woman desiring future fertility, no antibiotic is favored if the baseline infection risk is <0.8% or <0.9%, respectively. Treatment-dose antibiotics are favored if the risk of infection exceeds 4.7% or 5.7%, respectively. Otherwise, prophylactic antibiotics are favored for women desiring future fertility. For a 20 or 30-year old woman not desiring future fertility, no antibiotic is favored if the baseline infection risk is <0.9 % or <1.1%, respectively. Treatment-dose antibiotics are favored if the risk of infection exceeds 5.7% or 6.6%, respectively. Otherwise, prophylactic antibiotics are favored. Results were sensitive to varying relative infection risk between prophylactic and treatment regimens and the rate of side-effects but were robust to variation of other cost and outcome parameters.

Conclusions: Although age and desire for fertility influence the cost-effectiveness of antibiotic use, further study is needed to examine antibiotic use in settings with a low incidence of post-abortal infection and to compare prophylactic and treatment regimens directly. Further delineation of the sequelae of post-abortal infection is also needed.