If you are diagnosed with Bacterial Vaginosis, you have to complete a course of antibiotics that are considered safe to take during pregnancy. Sulfamethaxazole / trimethoprim (septran) and ceftriaxone are the drug of choice for treating these type of infections. It is imperative that antibiotic susceptibility testing to be performed to determine which antibiotics will work to treat these infections. So trust your doctor , take the medicines as prescribed by him. Do regular follow up. There is nothing to worry . stay healthy. Take care.