You take them when trying to concieve and during,they contain all the right nutrients needed for a healthy pregnancy.
When I was trying to get pregnant doctor's did recommend I take prenatal vitamins...I took it for four days and just forgot to take them again, but strangely the next month I was pregnant. So I can't really say they did help me but then again I can't say they didn't...I dunno...but I'm guessing prenatal pills do help you get pregnant and prepare the body...you know what, I'm not sure...Alot of doctors that I've seen have recommended taking prenatal vitamins...so...hmm..good question