Pregnancy and births: definitions

General

Abortion: A therapeutic abortion notified in accordance with the Abortion Act 1967. Sometimes referred to as a 'termination of pregnancy' or just a 'termination'.
Fertility rate: The general fertility rate is the number of live births per 1,000 women of child-bearing age (15-44 years). Age specific fertility rates are similar but constrained to certain age groups.
Low birthweight: birthweight less than 2,500g.
Maternity: A pregnancy resulting in one or more live or stillbirths.
Miscarriage: The spontaneous loss of a pregnancy before 24 weeks' gestation. May sometimes be referred to as a 'spontaneous abortion'.
Multiple pregnancy: A pregnancy involving twins, triplets or higher order multiples.
Preterm: Less than 37 weeks of gestation, i.e. less than 259 days (measured from the first day of the last normal menstrual period).
Singleton pregnancy: A pregnancy with only one baby.

Live birth: A child which at birth, having been completely expelled, shows signs of life or breathes.
Stillbirth: a child born after the 24th week of pregnancy which did not breathe or show any other sign of life. (Prior to 1992 this definition of stillbirth referred to the 28th week of pregnancy.)
Perinatal death: stillbirth or death in the first week of life.
Neonatal death: death in the first four weeks of life.
- Early: death in the first week of life.
- Late: death in weeks two to four of life.

Postneonatal death: death after the first four weeks of life but before the end of the first year.
Infant death: death in the first year of life.