What commonly causes a miscarriage?

According to the American Pregnancy Association (APA), the most common cause of miscarriage is a genetic abnormality in the embryo. But several other factors can also be the culprit, including thyroid disorders, diabetes, immunological disorders, drug abuse, and more.

What's the earliest you can get a miscarriage?

This sometimes happens even before a woman knows she is pregnant. Unfortunately, miscarriages are fairly common. A miscarriage usually happens in the first 3 months of pregnancy, before 12 weeks' gestation. A very small number of pregnancy losses are called stillbirths, and happen after 20 weeks' gestation.