Infections due to bacteria, virus or parasites are frequent during pregnancy and can have severe consequences. Moreover, the vaginal carriage of commensal bacteria or dramatic changes in the equilibrium of the vaginal flora can induce complications and cause fetal contaminations. With the help of the guidelines set up by the French Agency of Accreditation and Evaluation in Health (Anaes), the authors detail the microbiological exams and screening which take part in the management of different situations at risk.