Have you tried those calcium chews? Those had no effect on me. When I was pregnant I had terrible heartburn and reflux, even though I kept taking my Nexium. Some people don't think taking Nexium is a good idea, but my gastro doctor and I talked about it and decided it was absolutely crucial in my case to be able to carry a healthy pregnancy. I was lucky and didn't have too bad a time with the vitamins, but I took them with a big dinner. I took some I got at GNC that didn't have iron. If you can't manage the vitamins, I would say to eat a Luna Bar or something with a bunch of folic acid in it every day, and to make sure to get enough leafy green vegetables to get calcium and iron.