Inclusion Criteria:  Abnormal vaginal microbiota. The screening swab should be repeated if more than 3 months old. HIV, Hepatitis B or C positivity. First, second or third IVF stimulation cycle or embryo transfer therefrom. BMI<35 Written informed consent.  Exclusion Criteria:  Known or suspected hypersensitivity to clindamycin. HPV CIN 2 or higher. Former or current inflammatory bowel disease Severe concomitant disease, including diabetes. MAX 2 embryos may be transferred Artificial heart valve Intrauterine malformations with operation indication as determined by treating physician (Polyps, Septum, fibroma)