What is the most effective and safe way to administer antibiotics to prevent infection for women undergoing caesarean section

What is the issue?

Caesarean delivery increases the risk for infection compared to vaginal birth by five- to 20-fold. Infections can be of the surgical incision, the lining of the uterus, and inside the pelvis. Clinicians seek to prevent these infections by different measures including prophylactic (preventative) antibiotics.

Why is this important?

Antibiotics can be given by a number of different routes including by mouth, injection into a vein or by washing inside the uterus and the surgical site with a saline solution containing the antibiotic. We assessed the benefits and harms of different routes of prophylactic antibiotics given for preventing infections in women undergoing caesarean section.

What evidence did we find?

We searched for evidence from randomised controlled trials on 6 January 2016 and found 10 studies (involving a total of 1354 women).

Nine studies (1274 women) compared intravenous antibiotic administration with antibiotic irrigation (washing with a saline solution containing antibiotics). The two routes gave similar results on important outcomes including infection of the uterus/womb (low-quality evidence) and wound infection (very low-quality evidence). The studies did not report on blood infections in the newborn infant (sepsis). The numbers of women who had urinary tract infection (very low-quality evidence), serious infectious complications (very low-quality evidence) or fever after birth (very low-quality evidence) also did not clearly differ between groups. There was no clear difference between groups in terms of how long women spent in hospital and no data reported on the number of women who were readmitted to hospital. No women had allergic reactions to the antibiotics (very low-quality evidence) in the three studies that reported this outcome. None of the studies reported information about whether the babies had any immediate adverse reactions to the antibiotics.

One study (involving 80 women) compared intravenous antibiotics with taking antibiotics orally but it did not report on any of this review's outcomes.

What does this mean?

The studies included in this review did not clearly report how they were carried out and outcome data were incomplete. Too few women were included in each study for sufficient numbers of events to see a clear difference in outcomes between the two groups of women. This meant the evidence was of low quality. Therefore, we need to exercise caution in the interpretation and generalisability of the results.

High-quality studies are needed to determine the safest, most effective way of giving preventive antibiotics. Such studies should evaluate more recently available antibiotics and consider potential side effects that the intervention may have for the baby.

Authors' conclusions: 

There was no clear difference between irrigation and intravenous antibiotic prophylaxis in reducing the risk of post-caesarean endometritis. For other outcomes, there is insufficient evidence regarding which route of administration of prophylactic antibiotics is most effective at preventing post-caesarean infections. The quality of evidence was very low to low, mainly due to limitations in study design and imprecision. Furthermore, most of the included studies were underpowered (small sample sizes with few events). Therefore, we advise caution in the interpretation and generalisability of the results.

For future research, there is a need for well-designed, properly-conducted, and clearly-reported RCTs. Such studies should evaluate the more recently available antibiotics, elaborating on the various available routes of administration, and exploring potential neonatal side effects of such interventions.

Read the full abstract...
Background: 

Post-caesarean section infection is a cause of maternal morbidity and mortality. Administration of antibiotic prophylaxis is recommended for preventing infection after caesarean delivery. The route of administration of antibiotic prophylaxis should be effective, safe and convenient. Currently, there is a lack of synthesised evidence regarding the benefits and harms of different routes of antibiotic prophylaxis for preventing infection after caesarean section.

Objectives: 

The aim of this review was to assess the benefits and harms of different routes of prophylactic antibiotics given for preventing infectious morbidity in women undergoing caesarean section.

Search strategy: 

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 January 2016), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (6 January 2016) and reference lists of retrieved studies.

Selection criteria: 

We included randomised controlled trials (RCTs) comparing at least two alternative routes of antibiotic prophylaxis for caesarean section (both elective and emergency). Cross-over trials and quasi-RCTs were not eligible for inclusion.

Data collection and analysis: 

Two review authors independently assessed trials for inclusion, assessed the risk of bias and extracted data from the included studies. These steps were checked by a third review author.

Main results: 

We included 10 studies (1354 women). The risk of bias was unclear or high in most of the included studies.

All of the included trials involved women undergoing caesarean section whether elective or non-elective.

Intravenous antibiotics versus antibiotic irrigation (nine studies, 1274 women)

Nine studies (1274 women) compared the administration of intravenous antibiotics with antibiotic irrigation. There were no clear differences between groups in terms of this review's maternal primary outcomes: endometritis (risk ratio (RR) 0.95, 95% confidence interval (CI) 0.70 to 1.29; eight studies (966 women) (low-quality evidence)); wound infection (RR 0.49, 95% CI 0.17 to 1.43; seven studies (859 women) (very low-quality evidence)). The outcome of infant sepsis was not reported in the included studies.

In terms of this review's maternal secondary outcomes, there were no clear differences between intravenous antibiotic or irrigation antibiotic groups in terms of postpartum febrile morbidity (RR 0.87, 95% CI 0.48 to 1.60; three studies (264 women) (very low-quality evidence)); or urinary tract infection (RR 0.74, 95% CI 0.25 to 2.15; five studies (660 women) (very low-quality evidence)). In terms of adverse effects of the treatment on the women, no drug allergic reactions were reported in three studies (284 women) (very low-quality evidence), and there were no cases of serious infectious complications reported (very low-quality evidence). There was no clear difference between groups in terms of maternal length of hospital stay (mean difference (MD) 0.28 days, 95% CI -0.22 to 0.79 days, (random-effects analysis), four studies (512 women). No data were reported for the number of women readmitted to hospital. For the baby, there were no data reported in relation to oral thrush, infant length of hospital stay or immediate adverse effects of the antibiotics on the infant.

Intravenous antibiotic prophylaxis versus oral antibiotic prophylaxis (one study, 80 women)

One study (80 women) compared an intravenous versus an oral route of administration of prophylactic antibiotics, but did not report any of this review's primary or secondary outcomes.

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