Antibiotic prophylaxis and operative vaginal delivery

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The World Health Organization (WHO) currently does not recommend routine antibiotic prophylaxis for women undergoing operative vaginal birth because of insufficient evidence of effectiveness. But results of a new study in The Lancet may compel a change to that guidance.

Twenty-seven UK obstetric units participated in the blinded randomized controlled trial. Women aged 16 or older who had undergone operative vaginal birth at ≥ 36 weeks’ gestation were randomized to a single dose of intravenous amoxicillin and clavulanic acid or placebo. The primary outcome was confirmed or suspected maternal infection within 6 weeks of delivery based on a new prescription of antibiotics for specific indications, confirmed systemic infection on culture or endometritis. 

Of the women, 1715 were given amoxicillin and clavulanic acid and 1705 received placebo. Primary outcome data were missing for 195 women (6%). Baseline characteristics in both groups were similar. Seventy-seven percent of the women were primiparous and 49% had induction of labor. In addition, 13% of the participants had ruptured membranes for more than 24 hours before giving birth. Sixty-five percent of the births were by forceps and 35% were by vacuum extraction. 

The authors found that women in the amoxicillin and clavulanic acid group had significantly fewer confirmed or suspected infections (180 of 1619 [11%]) than those in the placebo group (306 of 1606 [19%]; risk ratio 0.58 ,95% CI 0.49-0.69; P < .0001). Adverse events were minimal in both groups. One woman in the placebo group reported a skin rash and two women in the amoxicillin and clavulanic acid group reported allergic reactions.

The authors say their findings show that antibiotic prophylaxis can significantly reduce incidence of infection after operative vaginal delivery while cautioning that ob/gyns do need to counsel their patients about possible allergic reactions. They suggested that WHO and other organizations adapt their guidance to reflect the benefits of antibiotic prophylaxis in this delivery setting.