Live Birth

A live birth is the complete delivery of a baby from the mother, after which the baby shows any sign of life. The length of the pregnancy does not affect this definition. The baby may be delivered spontaneously (expulsion) or removed (extraction). Signs of life include breathing, a heartbeat, a pulse in the umbilical cord, or definite movement of voluntary muscles, the muscles under the baby's own control. The birth counts whether or not the cord has been cut and whether or not the placenta is still attached.

This is the statistical definition of live birth from the World Health Organization and ICD-10. The ICD-11 Reference Guide gives the same core standard in shorter form: a fetus that shows any sign of life after complete delivery from the mother. MeSH and the National Cancer Institute Thesaurus use language that matches in substance. In all these sources, live birth is a yes-or-no outcome. It does not depend on the length of the pregnancy or on how long the baby lives after birth.

Live birth is not the same as a healthy birth. The definition sets a minimum threshold. Any sign of life immediately after delivery meets it. This holds regardless of the baby's gestational age, birth weight, or birth defects. It also holds with a stay in the neonatal intensive care unit (NICU) or with death soon after birth.

Many live births are followed by newborn complications, newborn death, or lifelong illness. Outcome measures that blur live birth with healthy birth conceal a real gap. Reaching delivery differs from reaching a healthy outcome for mother and baby.

Live birth is the primary outcome in fertility research. It captures the full chain of events that a successful pregnancy requires: conception, implantation, growth of the embryo and fetus, and intact delivery. Lesser endpoints are intermediate markers. One is a positive pregnancy test. Another is a pregnancy seen on ultrasound (clinical pregnancy). A third is a pregnancy that continues at twelve weeks. These markers often differ from live birth, especially in groups at high risk of pregnancy loss.

Outcome studies of restorative care prefer the cumulative live birth rate. This rate counts live births over a set treatment period, commonly 24 months. It reflects the fact that fertility care takes many cycles. It also avoids the inflated appearance of clinical pregnancy rates counted per cycle.

Comparison studies of NaProTechnology care report cumulative live birth rates. One is the Tham Canadian family-medicine cohort.¹ These rates show the course of couples treated with restorative care, in contrast with assisted reproductive technology.