I am 28 weeks now and have not taken any vitamins during pregnancy. I think folic acid is most important during the first trimester to prevent neural tube defects, but I didn't take that either. I had good intentions, but never remembered to take them. As for vitamins, they are huge and smell terrible, there is no way I can swallow them. As long as you eat a decent diet, baby will still get what it needs without suppliments.