There are many reasons you could get a yeast infection, including:
- Hormones. Hormonal changes during pregnancy, breast-feeding or menopause (or if you’re taking birth control pills) can change the balance in your vagina.
- Diabetes. If your diabetes isn't well-controlled, the rise in sugar in the mucus membranes (moist linings) of your vagina can create a place for yeast to grow.
- Antibiotics. These drugs can kill many of the bacteria that live in your vagina.
- Douches and vaginal sprays. These products can change the balance in your vagina.
- A weakened immune system. If you're HIV-positive or have another immune system disorder, the yeast may also grow uncontrolled.
- Sex. Though a yeast infection is not considered a sexually transmitted infection, it can be passed from person to person through sexual contact.