Fortunately, they do not! As irritating and uncomfortable a yeast infection may seem to be in pregnancy, it does not usually cause harmful effects in the mother or even in the baby who is yet to be born. However, the only thing that can happen, is that if you end up experiencing the yeast infection while you are having labor, it would perhaps transfer onto the baby during delivery. These then form white like patches in the mouth of the baby or in their diaper area that can return to you while you breastfeed. This is why you must get in touch with the doctor for aids to get rid of the infection from both, the mother and the baby.