...could be a yeast infection, especially if your daughter has thrush (oh, heavens, I remember thrush nipples -- yeeouch!). It may not be though, so it might be wise to hit a doctor for diagnosis. The other distinct possiblity, especially if you don't have that typical yeast discharge, is bacterial vaginosis. BV has potentially long-term effects if untreated. Usually, a dr. will give you this horrible antibiotic called Flagyl (mmm, nausea and a metallic taste in your mouth all day!).
WARNING: I just noticed you said you were pregnant. I don't know about the safety of this during pregnancy, so please find out for sure before trying this! What I have discovered is that tea tree oil is great for this (and this is actually well-documented by respectable sources). I believe it has also been found to be effective against yeast, but am not totally sure on that. If you want to try it, add two or three drops of oil to a cleansing bottle of lukewarm water, 8-12 drops to a bath, douche with the solution, or some folks soak a tampon in a water/tea tree oil solution (haven't tried that. so can't say if it's good). Always patch-test first -- swab your inner thigh with the diluted solution and wait a few hours, because nothing bites worse than an allergic reaction in THAT area. And always dilute the tea tree oil. BTW, if you've never used it, it smells like turpentine. Do not be alarmed.
But were I you, whatever treatment I chose, I'd get a diagnosis first, if this is an unfamiliar infection to you. Some infections down there are nasty buggers.