<prompt> Which one of the following is the best drug of choice for treatment of bacterial vaginosis during pregnancyClindamycinMetronidazoleErythromycinRovamycin  <response>: Although no drug is considered absolutely safe in the first trimester , there is a relative safety of usage of class B drugs in pregnancy. Metronidazole comes under that class where the drug is safe in animal studies and also in most human studies. If given a choice, its prudent to use an absolute safe agent like betadine vaginal pessary which will buy time till the patient is in the second trimester for safe usage of category B or even C category drugs. 