Does Plan B Cause Infertility?

Can Plan B make you infertile?

—Anonymous

No. Plan B is a pill that contains the hormone levonorgestrel, which is a synthetic form of progesterone. The pill prevents ovulation. It does not impact implantation or fertilization, so it works by preventing an egg from being released at all.

Your period in the current cycle may be late after taking Plan B because the pill delayed ovulation. However, there is no evidence associating taking Plan B with later infertility. Beyond delayed ovulation, there is simply no reason for such a link.