You should be able to treat it - just talk to your midwife/ob about what they would like you to use. All the packages of creams and pessaries say not to use during pregnancy, but my doctor said some kinds were fine.
Aside from that, you should try to cut back on refined flour (white bread, cookies, cake, etc.) and refined sugar.
And eat plain yogourt, and/or take acidophilus. Acidophilus you can get from a health food store as a tablet or a liquid (you'll need like 10 drops, if it's the same as it is here - barely any!). That's the bacteria that your body needs to balance the yeast. That should really help prevent future yeast infections. They are MISERABLE!!! I've had them occasionally with all my babies so far.
And I imagine you know the rest of the precautions - cotton underwear, stay as clean and dry as possible, no irritating soaps or cleaners....

I really recommend the acidophilus - it also works for thrush in your baby and on your nipples when you are nursing later. Knocks the extra yeast out of your whole system.