A miscarriage is the loss of a pregnancy during the first 20 weeks. It's usually the body's way of ending a problem pregnancy. A miscarriage can be hard to accept, but it's no one's fault and it can't be prevented.
You may need treatment if any tissue remains in the uterus after the miscarriage.
Things that may increase your risk of miscarriage include your age, especially at age 35 and older, and having a history of miscarriages (three or more). But most miscarriages happen because the fertilized egg in the uterus does not develop normally, not because of something you did.
Most miscarriages happen because the fertilized egg in the uterus doesn't develop normally. A miscarriage isn't caused by stress, exercise, or sex. In many cases, doctors don't know what caused the miscarriage. The risk of miscarriage is lower after the first 12 weeks of the pregnancy.