The birth of a living fetus (regardless of the length of gestation) WordNet 3.0 & Open English WordNet

In human reproduction, a live birth occurs when a fetus exits the mother showing any definite sign of life such as voluntary movement, heartbeat, or pulsation of the umbilical cord, for however brief a time and regardless of whether the umbilical cord or placenta are intact. Wikipedia

the event that a fetus is born alive with heartbeats or respiration Wikidata