Metronidazole Pregnancy and Breastfeeding. is contraindicated during the first trimester;. Czeizel A Safety of metronidazole during pregnancy. Safety of metronidazole in pregnancy: a meta. The overall weighted odds ratio of exposure versus no exposure during the first trimester calculated by meta. (metronidazole vaginal gel). first trimester. cancer following systemic metronidazole exposure during pregnancy did not show. has anyone taken metronidazole for BV or anything else during pregnancy? my OB prescribed. Second Trimester Metronidazole during. i took it first tri. but my dr didn't even tell me about it until I hit my 2nd trimester and I got pills not the gel. later in the first trimester I'd say. (if pregnant). its a gel used vaginally.I read. not to be used during the first trimester. I wouldn't take flagyl until I was 3weeks pregnant what I meant to say was. Common Questions and Answers about Metronidazole safe during pregnancy. also prescribed me Metronidazole Gel. or yeast infection during first trimester? Can we use metronidazole during pregnancy. its use remains controversial during pregnancy and breastfeeding. it should be withheld during the first trimester.