Miscarriage describes early pregnancy loss that occurs before 20 weeks gestation. Stillbirth is when a baby dies in the womb after 20 weeks. It's less common than miscarriage, affecting about 1 in 160 pregnancies. Stillbirth is often discovered when the pregnant person senses a lack of fetal movement or a second- or third-trimester ultrasound confirms that a baby has no heartbeat. Stillbirth rarely occurs amid labor these days, thanks to fetal monitoring.