Metronidazole is a contraindicated drug during pregnancy and should not be taken lightly. If taken during the formation of a fertilized egg, it will not have a significant effect on the fertilized egg. If you take this medication within 18 days after intercourse, it will not affect the fetus, but if you take it outside the first 18 days of pregnancy, it will have some effect on the fetus. If the fetus is in its first three months, the most important period of growth and development, if you take this drug for a longer period of time, it should not be a big problem if it does not cause a miscarriage. If you take it for a particularly long time, it will lead to the occurrence of fetal malformation rate, and you need to do a 4D examination of the baby later to determine whether there are any abnormalities in the baby.