Following a miscarriage, surgical intervention is needed in some cases to remove retained products of conception. Antibiotic prophylaxis may reduce the risk of pelvic infection, which is an important complication of this surgery, particularly in low-resource countries. The AIMS (Antibiotics in Miscarriage Surgery) trial was a double-blind, placebo-controlled, randomized trial investigating whether antibiotic prophylaxis before surgery to complete a spontaneous abortion would reduce pelvic infection among women and adolescents in low- and middle- income countries (LMICs).
Women were randomly assigned to a single preoperative dose of 400 mg of oral doxycycline and 400 mg of oral metronidazole or identical placebos. The primary outcome was pelvic infection within 14 days after surgery. Pelvic infection was defined by the presence of two or more of four clinical features (purulent vaginal discharge, pyrexia, uterine tenderness, and leukocytosis) or by the presence of one of these features and the clinically identified need to administer antibiotics.
The trial included 3412 participants in Malawi, Pakistan, Tanzania, and Uganda. Women were assigned to receive either antibiotic prophylaxis (1705 [50%] of 3412) or placebo (1707 [50%] of 3412). 158 (5%) of 3412 women developed pelvic infection within 2 weeks of surgery, of whom 68 (43%) were in the antibiotic prophylaxis group and 90 (57%) in the placebo group.
A cost-effectiveness analysis found that there is 97-98% probability that antibiotic prophylaxis is a cost-effective intervention at expected thresholds of willingness-to-pay per additional pelvic infection avoided. In terms of post-surgery antibiotics, the antibiotic prophylaxis group was US$0·27 (95% CI -0·49 to -0·05) less expensive per woman than the placebo group.
Therefore, the AIMS trial demonstrated that antibiotic prophylaxis is more effective and less expensive than no antibiotic prophylaxis for surgical management of miscarriage in a LMIC setting.