Under normal circumstances, Lactobacilli bacteria are dominant microbes of the vaginal microbiome, but there are a number of factors that can disrupt the balance and provide Candida with an opportunity to multiply, including hormonal changes during puberty or pregnancy, uncontrolled diabetes, immunosuppression, and the overuse of antibiotics.[1]
Weaker evidence suggests that other behaviors could also increase the risk of VVC, such as the use of estrogen-containing oral contraceptives, spermicides, douching, and frequently wearing tight, synthetic pants or undergarments (e.g., leggings, damp swimsuits).
VVC isn’t a sexually-transmitted disease (because it isn’t contracted exclusively through sexual activity) but it may be possible to contract it from a sexual partner. Condoms and hygienic sexual practices (like washing both sex toys and the external genitalia before and after sexual activity) can help prevent VVC from occurring by reducing the transfer of abnormal (or fecal) microbiota into the vagina.[2]