When you’re trying to conceive, it’s natural to wonder if supplements can boost your chances but not all vitamins are created equal. Dr. Erika Munch, a fertility specialist with Texas Fertility Center, spoke with BabyCenter about what to look for in a prenatal vitamin, what your body may actually need, and when supplements could do more harm than good.

“When pregnancy is on the line, taking excessive, unnecessary, or ineffective vitamins isn’t just wasteful,” says Dr. Munch. “It could be harmful to you or your baby, should you conceive.”

Read the article to learn which vitamins support reproductive health and which ones to avoid.