Research indicates that both caesarean birth and operative vaginal birth (forceps or vacuum extraction) are associated with an increased risk of postnatal infection. While multiple trials have shown the efficacy of antibiotic prophylaxis to prevent infection after caesarean birth, only one, small, underpowered trial assessed this efficacy following operative vaginal birth.

For a multi-center, blinded, randomized placebo-controlled trial published in The Lancet, Marian Knight, DPhil, and colleagues set out to investigate whether a single dose of intravenous co-amoxiclav (amoxicillin/clavulanic acid) administered immediately after operative vaginal birth effectively prevented confirmed or suspected maternal infection, and a range of other secondary outcomes. Among nearly 3,500 women, the researchers compared co-amoxiclav with a placebo.

We found that a single dose of co-amoxiclav significantly reduced the incidence of confirmed or suspected infection from 19% in the control group to 11% in the antibiotic group,” explains Dr. Knight. “Women randomized to the antibiotic group were also significantly less likely to experience confirmed systemic infection on culture (0.6% vs 1.5%) and were at significantly lower risk of most secondary outcomes compared with women randomized to placebo, including perineal wound infection, perineal pain, use of pain relief for perineal pain, wound breakdown, and any perineum-related outpatient, primary care, or home visits.”

With 11% of women still having confirmed or suspected infection after receiving antibiotic prophylaxis, Dr. Knight questions whether other interventions might reduce this rate further. “We did not collect information about the aseptic techniques used at the time of operative vaginal birth,” she adds “It is possible that further attention to aseptic technique at the time of birth may influence later outcomes. Further investigation of whether the efficacy of prophylaxis varied with timing of administration is warranted to further guide advice on how rapidly antibiotic prophylaxis should be administered, and to assess whether there is any evidence to suggest that pre-delivery or repeated administration may be more effective.”

In the meantime, Dr. Knight suggests that clinical practice be changed to “reflect the clear evidence of benefit of a single intravenous dose of prophylactic co-amoxiclav after operative vaginal birth.”