Yeast infections are a fungal infection, and not surprisingly, occur when balance of organisms or conditions in the body is disturbed. That means pH balance, bacterial balance, heat and moisture, sugar levels, and so on. For example, experts recommend cotton underpants as a general rule for their breathability.
Antibiotics disturb the balance of bacteria in the body. Between 25 and 70 percent of women, depending on studies, will get a yeast infection after taking antibiotics. That is actually extremely high. Definitely an antibiotic can help with a difficult infection, but because it can lead to other problems, you do want to make sure you are taking them only when absolutely necessary. Frequent taking of antibiotics has another social effect as bacteria slowly adapts and becomes resistant.
There are different camps when it comes to what causes and prevents yeast infections, but antibiotics are something most people agree can increase the chances of yeast infection. If you are interested in natural treatments, Yeast Infection No More is an ebook which approaches yeast infections from a holistic health angle.