I've been taking Gummy Prenatal Vitamins for my entire pregnancy and everything is going great. I have pretty bad morning sickness so I couldn't keep down the prenatal pills my midwife prescribed me. The lack of iron in the gummies actually makes them gentler on the stomach but, of course, it is still important to get an adequate amount of iron.
Just a note of caution: make sure the brand of prenatal gummies you get have calcium in them. I discovered that the ones I was taking didn't have it in it so I had to add a prenatal calcium and fiber gummy supplement.