Date: 14 May 2019
Using a single dose of antibiotic to prevent infections after assisted vaginal births would reduce antibiotic use by 17% and halve the rate of infection, according to a new NIHR-funded study which published in The Lancet.
Infection rates after a caesarean birth without antibiotic prophylaxis are estimated at 20-25% and up to 16% after an operative vaginal birth (involving forceps or vacuum extraction). Sepsis causes 11% of maternal deaths globally. For every woman who dies from pregnancy-related infection, 70 more have severe infection and survive often with long-term health consequences.
The use of antibiotics during birth by caesarean section is widely recommended but current World Health Organization and national guidelines, recognising the importance of antibiotic stewardship, do not recommend routine antibiotic prophylaxis for operative vaginal birth.
The ANODE (prophylactic ANtibiotics for the prevention of infection following Operative DElivery) study, investigated whether a single dose of antibiotic prevented maternal infection after operative vaginal birth.
Senior author, Professor Marian Knight, from the National Perinatal Epidemiology Unit (NPEU), Nuffield Department of Population Health, University of Oxford said ‘The trial showed a clear benefit of single dose prophylactic antibiotic after operative vaginal birth and both UK and World Health Organisation guidance should be changed to reflect this.’ She added ‘Almost one in five women experience an infective complication and our results show that this can be reduced by almost half with routine use of antibiotic prophylaxis at operative vaginal delivery. This equates to prevention of over 7,000 infections annually in the UK.’
Prof Knight noted, ‘We also assessed the effect of using prophylaxis on overall antibiotic use. We found that for each additional 100 doses of antibiotic used in prophylaxis, 168 treatment doses will be saved, representing a 17% overall reduction in antibiotic use with a policy of universal prophylaxis.’
The trial was conducted at 27 hospital obstetric units in the UK between March 2016 and June 2018. Overall, 65% of births to women in the trial were by forceps and 34.8% by vacuum extraction. 1,719 women received amoxicillin or clavulanic acid, and 1,708 were given a placebo (saline). The antibiotic or placebo was administered about three hours after the women had given birth. The researchers found that women who received the antibiotic had a statistically significantly lower rate of confirmed or suspected infection than women allocated the placebo.
Lead Health Economist, Associate Professor Oliver Rivero-Arias, said ‘The results of the ANODE trial also have implications for healthcare resources. Women who received amoxicillin or clavulanic acid prophylactically were statistically significantly less likely to report any GP, nurse or midwife home visits or hospital outpatient visits in relation to concerns about their wound healing compared to the placebo group. The total mean NHS costs per woman at six weeks after giving birth was estimated to be £52.60 less for women who received the single dose of antibiotic.’
Unlike many previous observational studies of infections after operative vaginal birth which only followed women until they were discharged from hospital, in the ANODE trial information on antibiotic prescription for presumed infection was collected from medical records both at the time of hospital discharge and by telephone interview six weeks after women gave birth.
The primary outcome was confirmed or suspected infection within six weeks of delivery, as defined by one of: a new prescription of antibiotics for presumed perineal wound-related infection, endometritis or uterine infection, urinary tract infection with systemic features or other systemic infection; confirmed systemic infection on culture; or endometritis.
Six weeks after giving birth, rates of perineal infection, perineal pain, use of pain relief for perineal pain, need for additional perineal care and wound breakdown were statistically significantly lower in the group who received a single dose of antibiotics. Importantly, given recent concerns over sepsis in the UK, highlighted by organisations such as the UK Sepsis Trust, women receiving antibiotic prophylaxis had a 56% reduction in the risk of confirmed systemic infection on culture compared to women receiving the placebo.
It is unclear whether prophylactic antibiotics administered orally would have the same preventative efficacy. Further analysis of the mechanism of action of a single dose of antibiotic is needed to investigate whether earlier administration, prenatal administration or repeated administration is likely to be more effective.
For further information on this study, please visit the NIHR Journals Library.
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