Effect of oral N‐acetyl cysteine on recurrent preterm labor following treatment for bacterial vaginosis

OBJECTIVE: To evaluate the effect of N-acetyl cysteine (NAC) on gestational age at delivery in women with previous preterm labor and bacterial vaginosis. METHODS: A randomized, double-blind, placebo-controlled trial with 280 women between 16 and 18 weeks of pregnancy who had 1 previous preterm birth and had just been successfully treated for bacterial vaginosis with metronidazole for 1 week. The women were randomized to receive 0.6 g of NAC per day plus 17-hydroxyprogesterone caproate (17-OHPC) or placebo plus 17-OHPC until 36 completed weeks of pregnancy or active labor. A vaginal swab was taken during labor. RESULTS: Reaching 36 weeks of pregnancy was more frequent (P<0.05) and gestational age at delivery was significantly higher in the NAC than in the placebo group (37.4 weeks+/-0.4 weeks vs 34.1 weeks+/-1.2 weeks, P<0.05). The discontinuation rate was 11.4% in the NAC group. CONCLUSIONS: Oral NAC was found to reduce the recurrence of preterm birth in patients with bacterial vaginosis.