Large for gestational age: Weight is above the 90th percentile at gestational age
Macrosomia: Weight is above a defined limit at any gestational age
Appropriate for gestational age: Normal birth weight
Small for gestational age: Weight is below the 10th percentile at gestational age
Low birth weight: Weight is below a defined limit at any gestational age
Birth weight is the weight 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 weight 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 weight being outside of the AGA is influenced by the parents in numerous ways, including:
The health of the mother, particularly during the pregnancy
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 weight and later-life conditions, including diabetes, obesity, tobacco smoking and intelligence.