If you've lost a baby before your pregnancy came to term, you've had a miscarriage. One out of six pregnancies ends in miscarriage, with 75 percent of these ending in the first 12 weeks. If you've had one miscarriage, you're not considered infertile, but miscarriage, also called spontaneous abortion, is considered to be a form of infertility. You might have problems with your reproductive system causing your body to abort the fetus. There can be many explanations for a miscarriage. If you have a history of spontaneous abortions and are trying to have a baby, it's a good idea to talk to a physician before you conceive. Being under a doctor's care before and during pregnancy is also a good idea.