If a woman loses a pregnancy after she's past her 20th week, it's called a stillbirth. Stillbirths are due to natural causes. They can happen before delivery or during delivery. Causes include:
In at least half of all cases, it is not possible to tell why the baby died.
If stillbirth happens before delivery, your health care provider may induce labor or perform a Cesarean section to deliver the fetus. In some cases, you can wait until you go into labor yourself. This usually happens within two weeks of stillbirth.
Counseling may help you cope with your grief. Later, if you do decide to try again, work closely with your health care provider to lower the risks. Many women who have a stillbirth go on to have healthy babies.
NIH: National Institute of Child Health and Human Development