Neverending Yeast Infections

I have had 10 yeast infections since giving birth 14 moths ago. I relate it to being pumped full of antibiotics at the hospital but now I can't seem to get the infections under control. I had never had a yeast infection until after giving birth.

I have tried: cotton underwear, no underwear, lower sugar intake, probiotics, tea tree oil, coconut oil. NOTHING HELPS! I know changes in hormones can add to the likelihood of infections but there's got to be something to help.

Am I missing something? Is there something else I should be trying to help prevent them? The only thing that gets rid of them is medication.

We would like to start trying for our second soon but I'm not sure if it's a good idea until I get these infections under control.