Routine antibiotics at cesarean section to reduce infection

Smaill FM, Gyte GML

Published Online:

January 20, 2010

Women undergoing cesarean section have a five to 20-fold greater chance of getting an infection compared with women who give birth vaginally. These infections can be in the organs within the pelvis, around the surgical incision and sometimes the urine. The infections can be serious, and very occasionally can lead to the mother’s death. The potential benefits of reducing infection for the mother need to be balanced against adverse effects such as nausea, vomiting, skin rash and rarely allergic reactions in the mother, and the risk of thrush and any effect of antibiotics on the 'friendly' gut bacteria in the baby. This review looked at whether antibiotics are effective at elective and emergency cesarean sections. It also studied the effect of giving the antibiotics before or after the cord is clamped. The review found 86 studies involving over 13,000 women. Routine use of antibiotics at cesarean section reduced the risk of fever and of wound, womb and urine infections in mothers. It also reduced the risk of serious complications of infections for the mothers. This was so whether the cesarean section was elective or emergency, and whether the antibiotics were given before or after clamping of the umbilical cord. However, none of the studies looked properly at possible adverse effects on the baby, for example, whether its use increased the risk of thrush. Similarly, it was unclear whether the routine use of antibiotics at cesarean section would contribute to increasing drug resistant strains of bacteria. Studies are needed on these two aspects of this intervention.

Abstract (click to read)

Background:

The single most important risk factor for postpartum maternal infection is cesarean section. Routine prophylaxis with antibiotics may reduce this risk and should be assessed in terms of benefits and harms.

Objectives:

To assess the effects of prophylactic antibiotics compared with no prophylactic antibiotics on infectious complications in women undergoing cesarean section.

Search strategy:

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (May 2009).

Selection criteria:

Randomized controlled trials (RCTs) and quasi-RCTs comparing the effects of prophylactic antibiotics versus no treatment in women undergoing cesarean section.

Data collection and analysis:

Two authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction.

Main results:

We identified 86 studies involving over 13,000 women. Prophylactic antibiotics in women undergoing cesarean section substantially reduced the incidence of febrile morbidity (average risk ratio (RR) 0.45; 95% confidence interval (CI) 0.39 to 0.51, 50 studies, 8141 women), wound infection (average RR 0.39; 95% CI 0.32 to 0.48, 77 studies, 11,961 women), endometritis (RR 0.38; 95% CI 0.34 to 0.42, 79 studies, 12,142 women) and serious maternal infectious complications (RR 0.31; 95% CI 0.19 to 0.48, 31 studies, 5047 women). No conclusions can be made about other maternal adverse effects from these studies (RR 2.43; 95% CI 1.00 to 5.90, 13 studies, 2131 women). None of the 86 studies reported infant adverse outcomes and in particular there was no assessment of infant oral thrush. There was no systematic collection of data on bacterial drug resistance. The findings were similar whether the cesarean section was elective or non elective, and whether the antibiotic was given before or after umbilical cord clamping. Overall, the methodological quality of the trials was unclear and in only a few studies was it obvious that potential other sources of bias had been adequately addressed.

Authors' conclusions:

Endometritis was reduced by two thirds to three quarters and a decrease in wound infection was also identified. However, there was incomplete information collected about potential adverse effects, including the effect of antibiotics on the baby, making the assessment of overall benefits and harms complicated. Prophylactic antibiotics given to all women undergoing elective or non-elective cesarean section is clearly beneficial for women but there is uncertainty about the consequences for the baby.

This record should be cited as:

Smaill FM, Gyte GML. Antibiotic prophylaxis versus no prophylaxis for preventing infection after cesarean section. Cochrane Database of Systematic Reviews 2010, Issue 1. Art. No.: CD007482. DOI: 10.1002/14651858.CD007482.pub2

Assessed as up to date:

November 6, 2009

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Primary Review Group:

Pregnancy and Childbirth Group

PEARLS - Practical Evidence About Real Life Situations (click to read)

Clinical question:

How effective are prophylactic antibiotics for women undergoing caesarean section?

Bottom line:

Compared with no treatment, prophylactic antibiotics reduced the incidence of endometritis following both elective and nonelective caesarean section by two-thirds to three-quarters and the incidence of wound infection by up to three-quarters. Postpartum febrile morbidity and the incidence of urinary tract infections were also decreased. Fewer serious complications were identified. The administration of prophylactic antibiotics before or after clamping of the cord seemed equally effective for women undergoing caesarean section. The antimicrobial agents most often used in the trials included ampicillin, a first generation cephalosporin (usually cefazolin), a second generation cephalosporin (cefoxitin, cefotetan, cefamandole or cefuroxime), metronidazole, penicillins with an extended spectrum of activity (eg, ticarcillin, mezlocillin or pipericillin), a beta-lactam/beta-lactamase inhibitor combination, and an aminoglycoside-containing combination.

Caveat:

Prophylactic antibiotics given to all women undergoing elective or non-elective caesarean section is clearly beneficial for women but there is uncertainty about the consequences for the baby. Studies did not assess potential adverse effects on the baby, and the rates of oral candidiasis were not reported. It was also unclear whether the routine use of antibiotics would contribute to increasing drug resistant strains of bacteria.

Context:

Women undergoing caesarean section have a 5-fold to 20-fold greater chance of an infection compared with women who give birth vaginally. These infections can be in the organs within the pelvis, around the surgical incision and sometimes in the urinary tract. The infections can be serious, and very occasionally can lead to the mother’s death. The potential benefits of reducing infection for the mother need to be balanced against adverse effects, such as nausea, vomiting, skin rash and rarely allergic reactions in the mother, and the risk of oral candidiasis and any effect of antibiotics on the “friendly” gut bacteria in the baby.

Cochrane Systematic Review:

Smaill FM and Gyte GML. Antibiotic prophylaxis versus no prophylaxis for preventing infection after caesarean section. Cochrane Reviews 2010, Issue 1. Article No. CD007482. DOI: 10.1002/14651858.CD007482.pub2. This review contains 86 studies involving over 13,000 participants.

Authored by:

Brian R McAvoy

Cochrane Primary Health Care Field

Health topics:

Pregnancy & childbirth > Caesarian section > Other interventions

Cochrane Summaries^beta

Independent high-quality evidence for health care decision making

Routine antibiotics at cesarean section to reduce infection

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