Editing Small for gestational age (section)

==Terminology==
If small for gestational age babies have been the subject of intrauterine growth restriction, formerly known as intrauterine growth retardation,<ref>{{cite web |url=http://www.emedicine.com/radio/topic364.htm |title=eMedicine - Intrauterine Growth Retardation|last=Dogra|first=Vikram S |access-date=2007-11-28 }}</ref> the term "SGA associated with intrauterine growth restriction" is used.
Intrauterine growth restriction refers to a condition in which a fetus is unable to achieve its genetically determined potential size. This functional definition seeks to identify a population of fetuses at risk for modifiable but otherwise poor outcomes. This definition intentionally excludes fetuses that are small for gestational age (SGA) but are not pathologically small.<ref name=ross>{{cite web |url=http://emedicine.medscape.com/article/261226-overview |title=eMedicine - Fetal Growth Restriction|last=Ross|first=Michael G |access-date=2010-02-25 }}</ref> Infants born SGA with severe short stature (or severe SGA) are defined as having a length less than 2.5 standard deviation scores below the mean.<ref>{{cite journal|last1=Clayton|first1=PE|last2=Cianfarani|first2=S|last3=Czernichow|first3=P|last4=Johannsson|first4=G|last5=Rapaport|first5=R|last6=Rogol|first6=A|title=Management of the child born small for gestational age through to adulthood: a consensus statement of the International Societies of Pediatric Endocrinology and the Growth Hormone Research Society.|journal=The Journal of Clinical Endocrinology and Metabolism|date=March 2007|volume=92|issue=3|pages=804–10|doi=10.1210/jc.2006-2017|pmid=17200164|doi-access=free|hdl=2108/45969|hdl-access=free}}</ref>

A related term is [[low birth weight]], defined as an [[infant]] with a [[birth weight]] (that is, mass at the time of birth<ref>[http://oasis.state.ga.us/oasis/help/mch.html Definitions] {{webarchive|url=https://web.archive.org/web/20120402214755/http://oasis.state.ga.us/oasis/help/mch.html |date=2012-04-02 }} from Georgia Department of Public Health. Date: 12/04/2008. Original citation: "Birthweight: Infant's weight recorded at the time of birth"</ref>) of less than {{Convert|2500|g|lboz|abbr=on}}, regardless of gestational age at the time of birth.
Other related terms include "very low birth weight", which is less than {{Convert|1500|g|lboz|abbr=on}}; and "extremely low birth weight", which is less than {{Convert|1000|g|lboz|abbr=on}}.<ref>{{cite web |url=http://www.emedicine.com/ped/topic2784.htm |title=eMedicine - Extremely Low Birth Weight Infant|last=Subramanian|first=KN Siva|access-date=2007-11-28 }}</ref> Normal weight at term delivery is {{Convert|2500-4200|g|lboz|abbr=on}}.{{cn|date=September 2024}}

SGA is not a [[synonym]] of low birth weight, very low birth weight, or extremely low birth weight.
For example, with a 35-week gestational age delivery, a weight of {{Convert|2250|g|lboz|abbr=on}} is appropriate for gestational age but is still low birth weight. One third of low-birth-weight neonates – infants weighing less than {{Convert|2500|g|lboz|abbr=on}} – are small for gestational age.{{cn|date=September 2024}}

There is an 8.1% incidence of low birth weight in developed countries and 6–30% in developing countries.  Much of this can be attributed to the health of the [[mother]] during [[pregnancy]]. One-third of babies born with a low birth weight are also small for gestational age. Infants that are born at low birth weights are at risk of developing [[neonatal infection]].{{citation needed|date=December 2020}}

Both low and high maternal serum Vitamin D (25-OH) are associated with higher incidence SGA in white women, although the correlation does not seem to hold for African American women.<ref>{{cite journal|url=http://jn.nutrition.org/content/140/5/999.full.pdf+html|last1=Bodnar|first=LM|last2=Catov|first2=JM|last3=Zmuda|first3=JM|last4=Cooper|first4=ME|last5=Parrott|first5=MS|last6=Roberts|first6=JM|last7=Marazita|first7=ML|last8=Simhan|first8=HN|title=Maternal serum 25-hydroxyvitamin D concentrations are associated with small-for-gestational-age births in white women|journal=Journal of Nutrition|date=May 2010|volume=140|issue=5|pages=999–1006|doi=10.3945/jn.109.119636 |pmid=20200114 |pmc=2855265 }}</ref>
{| class="wikitable"
|+Mean weight for gestational age at birth with standard deviation and 10th percentile calculated by Z-score<ref>{{Cite journal|last1=Talge|first1=Nicole M.|last2=Mudd|first2=Lanay M.|last3=Sikorskii|first3=Alla|last4=Basso|first4=Olga|s2cid=5895957|date=2014-05-01|title=United States Birth Weight Reference Corrected For Implausible Gestational Age Estimates|url=http://pediatrics.aappublications.org/content/133/5/844|journal=Pediatrics|language=en|volume=133|issue=5|pages=844–853|doi=10.1542/peds.2013-3285|issn=0031-4005|pmid=24777216|url-access=subscription}}</ref>
!Gestational age at birth (weeks)
!Mean weight (grams)
!SD
!10th%
|-
|22
|467
|92
|354
|-
|23
|553
|109
|416
|-
|24
|626
|129
|473
|-
|25
|714
|156
|529
|-
|26
|819
|186
|597
|-
|27
|935
|215
|677
|-
|28
|1073
|242
|770
|-
|29
|1211
|269
|882
|-
|30
|1396
|309
|1018
|-
|31
|1588
|336
|1166
|-
|32
|1800
|371
|1335
|-
|33
|2033
|405
|1538
|-
|34
|2296
|428
|1772
|-
|35
|2560
|440
|2021
|-
|36
|2799
|441
|2261
|-
|37
|3028
|456
|2477
|-
|38
|3209
|432
|2665
|-
|39
|3333
|419
|2810
|-
|40
|3417
|416
|2904
|-
|41
|3486
|422
|2958
|-
|42
|3512
|429
|2985
|-
|43
|3550
|444
|2981
|-
|44
|3505
|503
|2952
|}