 The vagina undergoes significant changes following childbirth, including a shift in the balance of bacteria present and an increase in inflammation. These changes are linked to long-term health outcomes such as infertility and preterm birth. Prior live births appear to reduce the likelihood of a favorable vaginal environment, while longer interpregnancy intervals seem to mitigate this effect. This article was authored by Elizabeth K. Costello, Daniel B. DiGilio, Ana Robaxevska, and others.