Birth weight and gestational age

Classifications

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

Baby weighed as AGA

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:

• Genetics
• The health of the mother, particularly during the pregnancy
• Environmental factors
• 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.

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 weight 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.^[1][2][3]

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 is significantly adverse to children to warrant inducing catch-up.[1]

Diabetes

Babies that have a low birth weight are thought to have an increased risk of developing type 2 diabetes in later life.^[4][5][6]

Intelligence

Some studies have shown a direct link between an increased birth weight and an increased intelligence quotient.^[7][8][9]

Effects on the mother

There is some evidence of a link between a child's birth weight and its mother's risk of cardiovascular disease.^[10]

See also

• Barker's hypothesis
• MOMO syndrome

Parent Support

[The MAGIC Foundation for Children's Growth][2]

References

External links

• "Understanding IUGR A Parent's Guide"
• MedlinePlus Encyclopedia Intrauterine growth restriction
• "Intrauterine Growth Restriction: Identification and Management" at the American Academy of Family Physicians (AAFP)
• "Intrauterine growth restriction (IUGR)" at Health System, University of Virginia
• Fetal Growth Restriction at eMedicine
• "Researchers link low birth weight to lower achievement"
• "Management of Suspected Fetal Macrosomia"
• "Vit D linked to baby birth weight" at BBC News, 25 April 2006
• Born in Bradford - 2006 cohort study into the causes of low birth weight and infant mortality in Bradford, UK
• Intrauterine Growth Restriction Help - IUGR factors and solutions
• The IUGR prognostic scale