Have you tried changing the time of day you take the vitamin? Taking it with a meal might help. If it continues to cause nausea, ask your doctor about changing the brand, since some vitamins seem to cause more problems than others. If you absolutely can't take them without feeling sick, talk to to doctor about stopping the vitamins or (substituting something like childrens' gummi vitamins) for awhile until you get over this stage of things. If you do stop, be sure you are getting all of the nutrients you need from a well balanced diet. The main difference between normal one a day vitamins and prenatal vitamins is the additional folic acid in the prenatals. Orange juice is one source of folic acid.