Preventative antibiotics halve childbirth infections

Maternal infections, including sepsis, could drop by half if a single dose of preventative antibiotics is given to all women whose childbirth involves forceps or vacuum extraction.

This would be equivalent to reducing maternal infections by 7000 cases every year in the UK and by around 5000 in the USA.¹

The study also found that for every additional 100 doses of antibiotic given prophylactically, 168 doses could be avoided due to fewer postdelivery infections — meaning that a policy of universal prophylaxis after birth could help to reduce antibiotic use by 17%.

Published in The Lancet, the study is believed to be the first randomised trial of its kind in the UK involving 3420 women from 27 obstetric units.

Infection rates

Infection rates after assisted vaginal birth without antibiotic prophylaxis are around 16% worldwide and up to 25% after caesarean section. In 2016, an estimated 19,500 women died because of pregnancy-related infections globally. Even in high-income settings, infections account for 1 in 20 maternal deaths, and as many as 1 in 8 in the USA. For every woman who dies from pregnancy-related infection, another 70 women develop a severe infection and survive often with long-term health consequences.

“These findings highlight the urgent need to change current WHO antibiotic guidelines and other guidance from organisations in the UK, North America and Australasia that do not recommend routine antibiotic prophylaxis for assisted childbirth,” said Professor Marian Knight from the University of Oxford, UK, who led the research.

A recent Cochrane review of 95 trials showed that giving antibiotics before caesarean section reduced wound infection, endometritis, and serious maternal infection by 60–70%, and the use of antibiotics during caesarean section is widely recommended. In contrast, evidence on the use of prophylactic antibiotics in assisted vaginal birth is limited to a small trial of 393 women.

To provide more evidence, the new study investigated whether a single dose of antibiotics prevented maternal infection in the six weeks after assisted vaginal birth in 3420 women (aged 16 years and older) giving birth in 27 hospital obstetric units across the UK.

Study method

Between March 2016 and June 2018, women were randomly assigned to receive intravenous amoxicillin and clavulanic acid (1715 women) or placebo (saline; 1705) within six hours of operative vaginal delivery. The researchers also assessed the effect of using prophylaxis on overall antibiotic use. Suspected or confirmed maternal infection within six weeks of giving birth was identified by a new prescription for antibiotics, confirmed systemic infection on culture or endometritis.

Overall, around two-thirds of babies were delivered by forceps and about a third by vacuum extraction.

Results suggested that women who received a single dose of antibiotics had significantly fewer suspected or confirmed infections than women given placebo.

Importantly, women receiving antibiotic prophylaxis were also much less likely to have confirmed culture-proven sepsis compared to those receiving placebo.

Rates of perineal wound infection or breakdown (burst stitches), perineal pain, use of pain relief for perineal pain and need for additional perineal care were also substantially lower in the group who received antibiotics compared to the placebo group. Additionally, women who received antibiotics were much less likely to report any GP, nurse or midwife home visits, or hospital outpatient visits due to their wound healing compared to the placebo group.

“With increasing recognition of the need to reduce unnecessary caesarean births, the incentive to minimise the harms associated with other types of assisted delivery are even greater,” said Professor Knight. “This simple intervention could also be used to prevent maternal infections in low- and middle-income countries in which intravenous antibiotics are available.”

The authors note several limitations, including that presumed rather than culture-proven infection was the primary outcome, and that only three-quarters of women were followed up for secondary outcomes, both of which could have influenced the results. They also point out that despite being given antibiotics, 1 in 10 women still had a suspected or confirmed infection, highlighting the importance of more studies to investigate the mechanism of action and whether earlier administration, prenatal administration or repeated administration is likely to be more effective. Finally, it is unclear whether oral prophylactic antibiotics would have the same preventative efficacy.

Reference

1.  Around 1 in 8 women in the UK have an assisted vaginal birth (104,000 women annually), which compares to around 1 in 25 in the USA and less than 1 in 100 in some low-income countries.

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