“…[22][23][24] For those evaluating the effect of abnormal vaginal flora, four used metronidazole, 9,11,16,19 six used clindamycin [12][13][14][15]17,20 and two used erythromycin. 10,18 For the three studies that principally assessed risk based on previous preterm delivery (with or without abnormal vaginal flora), one used metronidazole, 23 one used clindamycin 22 and one used a combination of metronidazole and erythromycin. 24 For the two studies assessing risk based on positive fetal fibronectin, one used metronidazole, 8 and the other a combination of metronidazole and erythromycin.…”