Inhuman reproduction, alive birth occurs when afetus exits apregnant female showing any definite sign of life, such asvoluntary movement,heartbeat or pulsation of theumbilical cord, for however brief a time, and regardless of whether the umbilical cord orplacenta are intact.[1] After the fetus leaves thewomb it is called aneonate. It is a "live birth" whether thebirth isvaginal or bycaesarean section, and whether the neonate is ultimately viable.
The definition of the term "live birth" was created by theWorld Health Organization in 1950, and is chiefly used for public health and statistical purposes. However, the term "live birth" was in common use long before 1950.[2]
In the United States, the term "born alive" is defined by federal law[3] known as theborn alive rule. Live births are recorded on a U.S. Standard Certificate of Live Birth, also known as abirth certificate.[4] The United States recorded 3,605,201 live births in 2020 which is a 4% decrease from 2019 and the 6th consecutive year of decline in births.[5]
Not all pregnancies result in live births. A woman may elect to end her pregnancy by inducedabortion. The natural death of anembryo or fetus before it isable to survive independently is termedmiscarriage or pregnancy loss.[6][7] Some use the cutoff of 20 weeks ofgestation for miscarriage, after which fetal death is known asstillbirth.[8] The death of the fetus or neonate at the end of the pregnancy, during labour and delivery, or just after birth, is counted asperinatal mortality.
Measured in weeks, gestational age is a term used to describe how far along a pregnancy is starting from the first day of the woman's last menstrual cycle to the current date.[9] A baby born "at term" is between the gestational age of 37 weeks to 41 weeks. Apreterm baby is born before the gestational age of 37 weeks. A pregnancy that lasts 41 weeks up to 42 weeks is calledlate-term and a pregnancy longer than 42 weeks is calledpost-term.[10] The general consensus is that a fetus is viable at 24 weeks, however, a live birth may occur earlier in gestation with the assistance fromneonatal intensive care unit (NICU) resources. Gestational age is the main determinant of whether a baby will be able to live and survive outside of theuterus.
While gestational age is the most significant predictor of fetal viability, the condition of the neonate at birth also significantly indicates how well it tolerates life outside the mother. Factors measured at birth include birth weight, head circumference, and body length. AnApgar score is given at the time of birth to report the status of the newborn infant and the response to resuscitation if needed.[11]
The maternal recovery period directly following the events of humanchildbirth, regardless of whether it is a live birth, is called thepostpartum period.
There is one case report of a woman having a live birth derived from a frozen embryo obtained before she began cancer treatment.[12]
