A Cochrane review included two trials with 842 symptomatic or asymptomatic pregnant women with trichomoniasis. In the first trial, metronidazole 2g was given on randomization + 2g after 48 hours repeated after 2 weeks, starting before 23 weeks of pregnancy. In the second trial, a single oral dose of benzoylmetronidazole 50ml (2g metronidazole equivalent) was given during the last trimester of pregnancy. In both trials around 90% of women were cleared of trichomonas in the vagina after treatment. In the first trial, the risks of preterm birth (relative risk (RR): 1.8; 95% confidence interval (CI): 1.2 to 2.7) and low birth weight (RR: 1.4; 95% CI: 0.9 to 2.1) were increased in the metronidazole group.