Reproductive medicine is a major challenge for many researchers working in the microbiome field.In fact many questions remain unanswered: from the association between the vaginal microbiome, bacterial vaginosis and HPV risk, to the variations observed in the vaginal microbiota composition during the menstrual cycle. The efforts of the researchers at the Karolinska Institutet, in Stockholm, led by Prof. Lars Engstrand, focus precisely on these areas. With the aim, as Engstrand explains, to reduce the incidence of preterm births and pregnancy loss.