Birth mass

Overview
Birth mass is the mass of a baby at its birth. It has direct links with the gestational age at which the child was born and can be estimated during the pregnancy by measuring fundal height. A baby born within the normal range of mass for that gestational age is known as appropriate for gestational age (AGA). Those born above or below that range have often had an unusual rate of development – this often indicates complications with the pregnancy that may affect the baby or its mother. The incidence of birth mass being outside of the AGA is influenced by the parents in numerous ways, including:
 * Genetics
 * The health of the mother, particularly during the pregnancy
 * Environmental factors, including exposure of the mother to secondhand smoke, pp. 198–205
 * Other factors, like multiple births, where each baby is likely to be outside the AGA, one more so than the other

There have been numerous studies that have attempted, with varying degrees of success, to show links between birth mass and later-life conditions, including diabetes, obesity, tobacco smoking and intelligence.

Conditions
Associated conditions include:


 * Large for gestational age
 * Small for gestational age

Influence on adult life
Studies have been conducted to investigate how a person's birth mass can influence aspects of their future life. This includes theorised links with obesity, diabetes and intelligence.

Obesity
A baby born small or large for gestational age (either of the two extremes) is thought to have an increased risk of obesity in later life.

GH therapy at a certain dose induced catch-up of lean body mass (LBM). However percentage body fat decreased in the GH-treated subjects. Bone mineral density SDS measured by DEXA increased significantly in the GH-treated group compared to the untreated subjects, though there is much debate over whether or not SGA (small for gestational age) is significantly adverse to children to warrant inducing catch-up.

Diabetes
Babies that have a low birth mass are thought to have an increased risk of developing type 2 diabetes in later life.

Intelligence
Some studies have shown a direct link between an increased birth mass and an increased intelligence quotient.