We have thrush. The doctor said it could have started right after delivery because the antibiotic I got for GBS made us more susceptible. They gave us both nystatin, hers to swab on her inner cheeks and tongue and mine I put on my nipples after she nurses. Plus they gave me Diflucan to take by mouth. Of course, all this started Monday, the same day my mom arrived for a week long visit. Thankfully Claire doesn't seem to be bothered by it.