I have had three yeast infections in four months. what could it be?

Let me advice you: Yeast infection can result from: antibiotic use which leads to a decrease in the amount of lactobacillus bacteria in your vagina and a change in your vaginal ph that allows yeast to overgrow pregnancy uncontrolled diabetes impaired immune system anything that changes the type and amount of bacteria normally present in the vagina, such as douching or irritation from inadequate vaginal lubrica.