Birth weight

Birth weight

Baby weighed as appropriate for gestational age.

Birth weight is the body weight of a baby at its birth.[1]

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.


  • Determinants 1
  • Abnormalities 2
  • Influence on adult life 3
    • Obesity 3.1
    • Diabetes 3.2
    • Intelligence 3.3
  • Poor Neonatal Care 4
  • Epidemiology 5
  • See also 6
  • References 7
  • External links 8


There are basically two distinct determinants for birth weight:

  • The duration of gestation prior to birth, that is, the gestational age at which the child is born
Relation of weight and gestational age.
  • The prenatal growth rate, generally measured in relation to what weight is expected for any gestational age.

The incidence of birth weight being outside what is normal is influenced by the parents in numerous ways, including:

  • Genetics
  • The health of the mother, particularly during the pregnancy. Intercurrent diseases in pregnancy are sometimes associated with decreased birth weight. For example, Celiac disease confers an odds ratio of low birth weight of approximately 1.8.[2]
  • Environmental factors, including exposure of the mother to secondhand smoke[3]
  • Economic status of the parents gives inconsistent study findings according to a review on 2010, and remains speculative as a determinant.[4]
  • Other factors, like multiple births, where each baby is likely to be outside the AGA (appropriate for gestational age), one more so than the other.
  • The average birth weight is 3.5 kg though the range of normal is between 2.5 and 5 kg (all but 5 % of newborns will fall into this range).


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.


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,[5][6] but it was also shown that this relationship is fully explained by maternal weight.[7]

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.[8]


Babies that have a low birth weight are thought to have an increased risk of developing type 2 diabetes in later life.[9][10][11]


Some studies have shown a direct link between an increased birth weight and an increased intelligence quotient.[12][13][14] Increased birth weight is also linked to greater risk of developing autism.[15]

Poor Neonatal Care

Recent evidence suggests that the effects of low birth weight are constant across developmental years, suggesting that poor neonatal care has long term impacts.[16]


Disability-adjusted life years out of 100,000 lost due to any cause in 2004.[17]
  no data
  less than 9,250
  more than 80,000

See also


  1. ^ Definitions from Georgia Department of Public Health. Date: 12/04/2008. Original citation: "Birthweight: Infant's weight recorded at the time of birth"
  2. ^ Tersigni C, Castellani R, de Waure C; et al. (2014). "Celiac disease and reproductive disorders: meta-analysis of epidemiologic associations and potential pathogenic mechanisms". Human Reproduction Update 20 (4): 582–93.  
  3. ^ "The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General".   pp. 198–205
  4. ^ Margerison Zilko CE (January 2010). "Economic contraction and birth outcomes: an integrative review". Hum Reprod Update 16 (4): 445–458.  
  5. ^ "3 stages of childhood may predict obesity risk - Fitness -". Retrieved 2007-11-28. 
  6. ^ Singhal A, Wells J, Cole TJ, Fewtrell M, Lucas A (1 March 2003). "Programming of lean body mass: a link between birth weight, obesity, and cardiovascular disease?". Am J Clin Nutr. 77 (3): 726–30.  
  7. ^ Parsons TJ, Power C, Manor O (December 2001). "Fetal and early life growth and body mass index from birth to early adulthood in 1958 British cohort: longitudinal study". BMJ 323 (7325): 1331–5.  
  8. ^ "GH Treatment Effects on Body Composition in SGA". Growth, Genetics & Hormones 24 (1). May 2008. 
  9. ^ "Low birth weight diabetes link". BBC News. 2005-02-25. Retrieved 2007-11-28. 
  10. ^ Gillman MW, Rifas-Shiman S, Berkey CS, Field AE, Colditz GA (March 2003). "Maternal gestational diabetes, birth weight, and adolescent obesity". Pediatrics 111 (3): e221–6.  
  11. ^ Rich-Edwards JW, Colditz GA, Stampfer MJ, et al. (1999). "Birthweight and the risk for type 2 diabetes mellitus in adult women". Ann Intern Med. 130 (4 Pt 1): 278–84.  
  12. ^ Matte TD, Bresnahan M, Begg MD, Susser E (August 2001). "Influence of variation in birth weight within normal range and within sibships on IQ at age 7 years: cohort study". BMJ 323 (7308): 310–4.  
  13. ^ "The Future of Children - Sub-Sections". Archived from the original on 2007-10-22. Retrieved 2007-11-28. 
  14. ^ Matte TD, Bresnahan M, Begg MD, Susser E (August 2001). "Influence of variation in birth weight within normal range and within sibships on IQ at age 7 years: cohort study". BMJ 323 (7308): 310–4.  
  15. ^ Lord C (April 2013). "Fetal and sociocultural environments and autism". The American Journal of Psychiatry 170 (4): 355–8.  
  16. ^ Figlio David, Guryan Jonathan, Karbownik Krzysztof, Roth Jeffrey (2014). "The Effects of Poor Neonatal Health on Children's Cognitive Development". American Economic Review 104 (12): 3921–55.  
  17. ^ "WHO Disease and injury country estimates". World Health Organization. 2009. Retrieved Nov 11, 2009. 

External links

  • MedlinePlus Encyclopedia Intrauterine growth restriction
  • Peleg D, Kennedy CM, Hunter SK (August 1998). "Intrauterine growth restriction: identification and management". Am Fam Physician 58 (2): 453–60, 466–7.  
  • "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
  • Walid MS, Astafyeva OV, Pomortsev AV (December 2007). "The IUGR prognostic scale". Arch Gynecol Obstet. 276 (6): 633–40.