Why do you have to wait to become pregnant after dilation and curettage?

You don't. Older dictum was to wait for 3-6 months after a miscarriage before resuming sexual activity. More recent studies show that women who wait have lower fertility rates than women who don't. So, if you are trying to get pregnant, you can determine when you feel ready to resume sexual activity. Take Folic Acid 1-5 mg daily to prevent preterm birth, neural tube and cardiac anomalies in your offspring!