Stillbirth is often defined as fetal death after 20 weeks of gestation. A wide variety of definitions exist. Once the fetus has died, the mother may or may not have contractions and undergo childbirth or in some cases, a Caesarean section. Most stillbirths occur in full-term pregnancies.The cause is often unknown.The term is often used in distinction to live birth (the baby was born alive, even if it died shortly thereafter) or miscarriage (early pregnancy loss).