May 14, 2019
Prophylactic antibiotic administration within 6 hours of assisted vaginal delivery can dramatically reduce infection rates in the 6-week post-delivery period. These are the results of a blinded, randomized, placebo-controlled trial published online May 13 in The Lancet.
"From our results, a high proportion of women — almost one in five —experience an infective complication and this can be reduced by almost half," write Marian Knight, MBChB, DPhil, FFPH, FRCPE, from the University of Oxford, United Kingdom, and colleagues.
"This equates to prevention of more than 7000 infections annually in the UK with associated perineal complications, and around 5000 per year in the USA with routine use of antibiotic prophylaxis at operative vaginal delivery," note the authors.
Conducted across 27 hospital obstetric units in the UK, Knight and colleagues enrolled 3427 women (aged 16 years or older) between March 2016 and June 2018. Women were allocated to receive a single intravenous dose of amoxicillin (1 g) and clavulanic acid (200 mg) or placebo (20 mL intravenous sterile 0.9% saline) immediately following operative vaginal birth.
Operative vaginal delivery included the use of forceps or vacuum assistance and all deliveries were performed at 36 weeks' gestation or later. The study excluded women with any indication for antibiotic administration following delivery.
The researchers evaluated available medical record data within 6 weeks of delivery to identify new antibiotic prescriptions dispensed for "presumed perineal wound-related infection, endometritis or uterine infection, urinary tract infection with systemic features (pyelonephritis or sepsis) or other systemic infection (clinical sepsis); confirmed systemic infection on culture; or endometritis."
Only 11% (180/1619) of women in the antibiotic group developed an infection compared with 19% (306/1606) in the placebo group (risk ratio 0.58; 95% confidence interval, 0.49 – 0.69).
In the secondary outcome analysis, significantly less women in the antibiotic group reported perineal pain, need for perineal care, or wound breakdown when compared with women in the placebo group.
The study authors note that further studies are needed regarding route and timing of antibiotic administration and acknowledge that, while not all infections were confirmed with culture (given that microbiological confirmation is often not possible), the study outcome definition enhances the generalizability of their findings.
"[The trial] provides evidence of benefit of prophylactic antibiotic administration after operative vaginal birth, with few observed adverse events in relation to the intervention, indicating an urgent need to change current clinical practice to prevent maternal morbidity," conclude Knight and colleagues.
In an accompanying editorial, Vincenzo Berghella, MD, from Thomas Jefferson University in Philadelphia, Pennsylvania, and Federica Bellussi, from the University of Bologna, Italy, note that these study results are "practice changing."
Berghella and Bellussi point out that, even using a conservative estimate of 2% operative vaginal deliveries globally, use of prophylactic antibiotics could prevent 432,000 maternal infections.
The editorialists acknowledge that further data is required, including information on the effect of antibiotics on breast-feeding infants as well as a subgroup analysis of women who did not have an episiotomy, and therefore may not benefit from antibiotic therapy.
Funding for the study was provided by the National Institute for Health Research HTA Programme. The study authors and editorialists have disclosed no relevant financial relationships.