Prenatals are the single most important thing to do during pregnancy. You need to talk to your doctor to get an alternate route of administering so baby can get what they need.

They were just huge. I didn't have any side effects

Side effects? Call a doctor, or nurse hotline 24hr. And switch the type of prenatal you take unless you find out your allergic to a major vitamin, but I don't see how since most of them you get through food..etc anyways