Prophylactic antibiotic administration during second and third trimester in pregnancy for preventing infectious morbidity and mortality

BACKGROUND: Some previous studies have suggested that prophylactic antibiotics given during pregnancy improved maternal and perinatal outcomes, some have shown no benefit and some have reported adverse effects. OBJECTIVES: To determine the effect of prophylactic antibiotics during second and third trimester of pregnancy on maternal and perinatal outcomes. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (June 2009) and reference lists of articles. We updated this search on 2 September 2010 and added the results to the Awaiting classification section of the review. SELECTION CRITERIA: Randomized controlled trials comparing prophylactic antibiotic treatment with placebo or no treatment for women in the second or third trimester of pregnancy before labour. DATA COLLECTION AND ANALYSIS: We assessed trial quality and extracted data. MAIN RESULTS: The review included nine randomized controlled trials. Eight trials recruited 2508 women to detect the effect of prophylactic antibiotic administration on pregnancy outcomes. One additional trial recruited 715 women but did not report on the outcomes of interest. Antibiotic prophylaxis reduced the risk of prelabour rupture of membranes (risk ratio (RR) 0.34; 95% confidence interval (CI) 0.15 to 0.78 (one trial, 229 women)). There was a reduction in risk of preterm delivery (RR 0.64; 95% CI 0.47 to 0.88, one trial, 258 women) in pregnant women with a previous preterm birth and had bacterial vaginosis (BV) during the current pregnancy, but there was no reduction in pregnant women with previous preterm birth without BV during pregnancy (RR 1.08; 95% CI 0.66 to 1.77; two trials, 500 women). There was reduction in the risk of postpartum endometritis (RR 0.55; 95% CI 0.33 to 0.92; one trial, 196 women) in all risk pregnant women (with/without previous preterm birth and had bacterial vaginosis (BV) during the current pregnancy). Regarding the route of antibiotic administration, vaginal antibiotic prophylaxis during pregnancy did not prevent infectious pregnancy outcomes. AUTHORS' CONCLUSIONS: Antibiotic prophylaxis given during the second or third trimester of pregnancy reduces the risk of prelabour rupture of membranes and postpartum endometritis when given routinely to pregnant women. However there was also a possible substantial bias in the review's results because of a high rate of loss to follow up and small numbers of studies for each of our analyses. So we conclude that there is not enough evidence to recommend the use of routine antibiotics during pregnancy to prevent infectious adverse effect on pregnancy outcomes.