No need for bacterial vaginosis screening in women with low-risk pregnancy

France: Early antibiotic treatment for bacterial vaginosis in women with low-risk pregnancies does not reduce the risk for late miscarriage or spontaneous very preterm birth, suggests results of a large randomized, controlled trial.

The study, involving more than 84,000 pregnant women at 40 French hospitals, published in The Lancet, found that the rate of late miscarriage and spontaneous very preterm birth was nearly equal in women with low-risk pregnancies who were randomly assigned to receive clindamycin or a placebo before 15 weeks' gestation.

"Our findings indicate that antibiotic treatment for women with no history of late miscarriage or preterm delivery should be reconsidered," write the authors.

Preterm delivery during pregnancy (<37 weeks' gestation) is a leading cause of perinatal mortality and morbidity. Previous research has suggested that treatment of bacterial vaginosis during pregnancy can reduce poor outcomes, such as preterm birth.

Rodrigue Dessein, Recherche Translationelle Relation Hôte-Pathogènes (EA7366), Universitiare de Lille, Lille, France, and colleagues carried out this PREMEVA (Prevention of Very Preterm Delivery by Testing for and Treatment of Bacterial Vaginosis) trial to investigate whether treatment of bacterial vaginosis decreases late miscarriages or spontaneous very preterm birth.

For the purpose, the researchers screened 84 530 pregnant women before 14 weeks' gestation. 5630 had bacterial vaginosis, of whom 3105 were randomly assigned to groups in the low-risk trial (n=943 to receive single-course clindamycin, n=968 to receive triple-course clindamycin, and n=958 to receive placebo) or high-risk subtrial (n=122 to receive single-course clindamycin and n=114 to receive triple-course clindamycin).

The primary outcome was a composite of late miscarriage (16–21 weeks) or spontaneous very preterm birth (22–32 weeks).

• In 2869 low-risk pregnancies, the primary outcome occurred in 22 (1·2%) of 1904 participants receiving clindamycin and 10 (1·0%) of 956 participants receiving placebo.


• In 236 high-risk pregnancies, the primary outcome occurred in 5 (4·4%) participants in the triple-course clindamycin group and 8 (6·0%) participants in the single-course clindamycin group.


• In the low-risk trial, adverse events were more common in the clindamycin groups than in the placebo group (58 [3·0%] of 1904 vs 12 [1·3%] of 956.


• The most commonly reported adverse event was diarrhea (30 [1·6%] in the clindamycin groups vs 4 [0·4%] in the placebo group); abdominal pain was also observed in the clindamycin groups (9 [0·6%] participants) versus none in the placebo group.


• No severe adverse event was reported in any group.


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  Adverse fetal and neonatal outcomes did not differ significantly between groups in the high-risk subtrial.

These results indicate that treatment of vaginal dysbiosis during low-risk pregnancy is unlikely to affect risk for late miscarriage or very preterm birth. However, it's important to note that only 7% of women in this study population had vaginal dysbiosis, limiting the ability to draw inferences about pregnant women in the U.S. (25% of whom have the condition).

"Systematic screening and subsequent treatment for bacterial vaginosis in women with low-risk pregnancies shows no evidence of risk reduction of late miscarriage or spontaneous very preterm birth. Use of antibiotics to prevent preterm delivery in this patient population should be reconsidered," concluded the authors.