In human reproduction, a live birth occurs when a

fetus A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal dev ...

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 The placenta is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate mate ...

are intact. After the fetus is expelled from the maternal body it is called a neonate. Whether the

birth Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiated by hormones which cause the muscular walls of the uterus to contract, expelling the f ...

vagina In mammals, the vagina is the elastic, muscular part of the female genital tract. In humans, it extends from the vestibule to the cervix. The outer vaginal opening is normally partly covered by a thin layer of mucosal tissue called the hymen ...

l or by

Caesarean section Caesarean section, also known as C-section or caesarean delivery, is the surgical procedure by which one or more babies are delivered through an incision in the mother's abdomen, often performed because vaginal delivery would put the baby or m ...

, and whether the neonate is ultimately viable, is irrelevant. The definition of the term "live birth" was created by the

World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level o ...

in 1950, and is chiefly used for public health and statistical purposes. However, the term "live birth" was in common use long before 1950. In the United States, the term "born alive" is defined by federal law known as the born alive rule. Live births are recorded on a U.S. Standard Certificate of Live Birth, also known as a

birth certificate A birth certificate is a vital record that documents the birth of a person. The term "birth certificate" can refer to either the original document certifying the circumstances of the birth or to a certified copy of or representation of the ensui ...

. 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. Not all pregnancies result in live births. A woman may choose to end her pregnancy by

abortion Abortion is the termination of a pregnancy by removal or expulsion of an embryo or fetus. An abortion that occurs without intervention is known as a miscarriage or "spontaneous abortion"; these occur in approximately 30% to 40% of pre ...

Miscarriage Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the death of an embryo or fetus before it is able to survive independently. Miscarriage before 6 weeks of gestation is defined by ESHRE as biochemica ...

, also known as spontaneous abortion and pregnancy loss, is the natural death of an

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

or fetus before it is able to survive independently. Some use the cutoff of 20 weeks of

gestation Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pr ...

, after which fetal death is known as a

stillbirth Stillbirth is typically defined as fetal death at or after 20 or 28 weeks of pregnancy, depending on the source. It results in a baby born without signs of life. A stillbirth can result in the feeling of guilt or grief in the mother. The term ...

. The death of the fetus or neonate at the end of the pregnancy, during labour and delivery, or just after birth is counted as

perinatal mortality Perinatal mortality (PNM) refers to the death of a fetus or neonate and is the basis to calculate the perinatal mortality rate. Variations in the precise definition of the perinatal mortality exist, specifically concerning the issue of inclusion o ...

Statistical significance

Factors affecting viability

Gestational age

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. A baby born "at term" is between the gestational age of 37 weeks to 41 weeks. A preterm baby is born before the gestational age of 37 weeks. A pregnancy that lasts 41 weeks up to 42 weeks is called late-term and a pregnancy longer than 42 weeks is called post-term. The general consensus is that a fetus is viable at 24 weeks, however, a live birth may occur earlier in gestation with the assistance from

neonatal intensive care unit A neonatal intensive care unit (NICU), also known as an intensive care nursery (ICN), is an intensive care unit (ICU) specializing in the care of ill or premature newborn infants. Neonatal refers to the first 28 days of life. Neonatal care, as k ...

(NICU) resources. Gestational age is the main determinant of whether a baby will be able to live and survive outside of the

uterus The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The ...

Other factors

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 of the mother. Factors measured at birth include birth weight, head circumference, and body length. An

Apgar score The Apgar score is a quick way for doctors to evaluate the health of all newborns at 1 and 5 minutes after birth and in response to resuscitation. It was originally developed in 1952 by an anesthesiologist at Columbia University, Virginia Apgar ...

is given at the time of birth to report the status of the newborn infant and the response to resuscitation if needed.

Recovery

The maternal recovery period directly following the events of human

childbirth Childbirth, also known as labour and delivery, is the ending of pregnancy where one or more babies exits the internal environment of the mother via vaginal delivery or caesarean section. In 2019, there were about 140.11 million births glob ...

, regardless of whether it is a live birth, is called the

postpartum period The postpartum (or postnatal) period begins after childbirth and is typically considered to end within 6 weeks as the mother's body, including hormone levels and uterus size, returns to a non-pregnant state. The terms puerperium, puerperal peri ...

Neonate

What is Neonate?

Birthing child

Complications

Society and culture

History

Special cases

There is one case report of a woman having a live birth derived from a frozen embryo obtained before she began cancer treatment.

References

{{DEFAULTSORT:Live Birth Obstetrics Demography Midwifery Infancy Reproduction in mammals Childbirth