Included studies

One Cochrane systematic review (Liabsuetrakul 2020), which 2 included randomised controlled trials (RCTs) (Heitmann 1989 and Knight 2019) was included in this review.

One RCT (Heitmann 1989) compared prophylactic antibiotics given postnatally to no treatment. One RCT (Knight 2019) compared prophylactic antibiotics given postnatally to placebo.

Studies were from the United Kingdom and the United States.

The included studies are summarised in Table 2.

See the literature search strategy in appendix B and study selection flow chart in appendix C.

Excluded studies

Studies not included in this review are listed, and reasons for their exclusion are provided in appendix J.

Included studies

One economic study was identified which was relevant to this question (Knight 2019).

See the literature search strategy in appendix B and economic study selection flow chart in appendix G.

Excluded studies

Economic studies not included in this review are listed, and reasons for their exclusion are provided in appendix J.

The outcomes that matter most

As the main aim following prophylactic use of antibiotics is a reduction in the risk of infection, the committee chose endometritis, infection at the perineal or vaginal episiotomy site, and sepsis following perineum infection or endometritis, as the critical outcomes for this review. They agreed that all 3 outcomes would provide information regarding the efficacy of prophylactic antibiotics at reducing the risk of local infections following assisted vaginal birth. They also agreed that this would provide information on whether antibiotics reduce the risk of any systematic infections that develop following local perineum infections or endometritis.

The committee also agreed to look at maternal adverse reactions as an important outcome, as it was necessary to consider any of the harms associated with antibiotic use. The committee also chose to include long term neonatal outcomes such as asthma and allergies. They discussed that antibiotics could have an effect on the neonatal immune system, if given immediately before birth, and also after birth if the woman is breastfeeding. They agreed this longer term outcome could provide an insight into the impact of antibiotic use in early neonatal life. The committee also wanted to find out whether prophylactic antibiotics had an impact on a breastfeeding rates at 6 weeks postnatal, as it would be key to inform women if antibiotics have an effect on breastfeeding. Perineal pain at 6 weeks was also an important outcome chosen by the committee as it affects the quality of a woman’s life. Antibiotic resistance was another outcome the committee chose as important due to emergence of bacteria with resistance to many different types of antibiotics.

The quality of the evidence

The quality of the evidence for outcomes was assessed with GRADE and was rated as moderate to low. All of the evidence was downgraded for indirectness as there was not enough information regarding non-cephalic presentations in the population. Some of the evidence was also downgraded for risk of bias, with some concerns around concealment of randomisation and not enough information to judge selective reporting. Most of the evidence was also downgraded for imprecision around the estimate of effect.

Benefits and harms

The committee discussed the evidence for prophylactic antibiotics use following vaginal birth with forceps or ventouse, which showed a benefit for prophylactic antibiotics at reducing the rates of endometritis and infected episiotomy/lacerations.

The committee discussed whether there were any adverse outcomes associated with prophylactic antibiotics. They agreed that the evidence suggested there was no difference in maternal adverse reactions or perineal pain at 6 weeks, and that there was evidence showing that there was no difference between groups on breastfeeding at 6 weeks. They agreed that the evidence supported the use of prophylactic antibiotics in terms of endometritis and infection at the episiotomy or laceration site, and did not lead to any harms. Births with forceps or ventouse have a higher chance of needing an episiotomy, so the committee discussed whether the source of infection is due to the instrument used or the episiotomy. Based on their personal experience and expertise, they noted that infections are usually due to the increased number of examinations needed for an assisted birth. Coupled with these factors, the committee agreed that the evidence supported a recommendation for prophylactic antibiotics following a birth with forceps or ventouse.

The committee considered the evidence to guide their recommendations for a specific antibiotic type. They discussed that cefotetan, as used in one of the studies showing a benefit for endometritis, is a second generation cephalosporin not currently used in the UK, and therefore they could not recommend this antibiotic specifically, but agreed that cefuroxime would be an equivalent available in the UK. The committee discussed that the evidence which used co-amoxiclav (a mixture of penicillin and clavulanic acid) was from the UK and would therefore be directly applicable to practice in the UK. They agreed with the reasons stated in the study for co-amoxiclav use, such as the wide spectrum of activity which is important considering contamination with bacteria around the perineum region. However, the committee discussed that co-amoxiclav used antenatally has an increased risk of necrotising enterocolitis to the neonate. They agreed that they would include in the recommendation that co-amoxiclav should be given postnatally to prevent this. The committee also included in their recommendation that the co-amoxiclav should be administered no more than 6 hours after cord clamping, as this was in line with the time of administration used in the study.

The committee also specified that the route of administration for the antibiotics should be IV, based on the evidence which had used this route. They discussed the availability of IV antibiotics across different birth places, and whether limiting to IV would have an impact on access. They agreed that this was unlikely to be an issue as assisted vaginal births only take place in settings where IV antibiotics are available (alongside midwifery units and obstetric units).

The committee recognised that co-amoxiclav may not be appropriate for all women: hospitals may have different antibiotic resistance profiles and some women may be allergic to penicillin, therefore they included that a local alternative could also be used.

The committee discussed that that the evidence only supported IV administration, but IV administration requires 2 trained staff to check and administer the antibiotic, therefore it may be preferable for oral antibiotics to be used. The committee wanted to know whether oral antibiotics would be effective as prophylaxis for postnatal infections. They agreed a research recommendation was necessary and made one to address this gap in evidence.

Cost effectiveness and resource use

One study (Knight 2019) undertook a within trial cost analysis of prophylactic antibiotic for preventing postnatal infections in birth with forceps or ventouse. It found that overall, when compared to placebo, that antibiotics produced a mean cost saving of £52.60 per woman. This was driven by statistically significant reductions in GP visits, home visits by a midwife or nurse and outpatient hospital visits. An important limitation of this study was that the characteristics of women who returned the postal questionnaire, which captured data on resource use, differed systematically from those women who did not return the questionnaire. However, a sensitivity analysis involving imputation of missing data values reported a very similar mean cost saving £50.90. However, the cost analysis omitted staff costs to administer the antibiotic and all consumables apart from the drug cost. Therefore, the committee acknowledged that the cost saving was probably overstated by the analysis. However, given the “downstream” savings demonstrated by the cost analysis and improvements to health-related quality of life arising from lower infection rates, the committee considered that prophylactic antibiotics were likely to be cost-effective. According to NHS episode hospital statistics there are approximately 70,000 births with forceps or ventouse per annum (https://digital.nhs.uk/data-and-information/publications/statistical/nhs-maternity-statistics/2020-21) and the committee reasoned that given this size of population and “downstream” savings in resource use, from reduced outpatient hospital visits and other contacts with healthcare professionals, that their recommendations were unlikely to have a significant resource impact.

Other factors the committee took into account

The committee discussed one of the specifications of the protocol regarding instrument type. They had hoped to find evidence to determine if the benefits of prophylaxis antibiotic were dependent on the type of instrument used (vacuum, forceps or sequential). In the absence of direct evidence to address this stratified analysis, the committee used a post-hoc analysis from the ANODE study (Knight 2019) that looked at a composite measure of suspected and maternal infections, stratified by type of instrument used. The data for this outcome showed a benefit of prophylaxis antibiotics on forceps use and vacuum extraction. Although this outcome did not specifically meet the criteria of the protocol, as it could include other infections not related to instrumental birth, the committee agreed that it was useful for providing reassurance that in principle there are no differences in the benefits of antibiotics between types of instrument.