Can anyone explain why hiv causes more frequent yeast infections in women?

it doesn't seem like getting a yeast infection has anything to do with how weak of strong your immune system is.

A yeast infection, like ringworm, jock itch, and athletes' foot is caused by a fungus. In the case of a yeast infection, women have this fungus growing in their vaginas most of the time, but when that fungus begins to grow out of control, you get a yeast infection.
Your body has natural defenses against fungi such as this, but when your immune system is compromised, your body doesn't have the resources to fight the fungal infection.

Yeast cells are present in our body at all times it's just that when the immune system is not as strong - the yeast cells can mulitply to create a problem.

Yeast infections are opportunistic - that is they wait until the body's defenses are down and spring upon the body - shingles is another opportunistic infection, so is PCP pneumonia.

When the CD4 count is dropping - so is the ability to fight off the infections that we are exposed to everyday.

HIV attacks the immune system. Your immune system is what helps you fight off infections. when your immune system is down because of HIV you cant fight off bacteria as well. This is why.