Ajay Kumar at 20:47, 29 August 2023

2023-08-29T20:47:32Z

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{{Lead too short|date=October 2021}}
[[File:Nina_wcześniak.jpg|thumb|Low birth weight may be a result of [[preterm birth]].]]
'''Low birth weight''' ('''LBW''') is defined by the [[World Health Organization]] as a [[birth weight]] of an
[[infant]] of {{convert|2499|g|lboz|abbr=on}} or less, regardless of [[Gestational age (obstetrics)|gestational age]].<ref>[http://apps.who.int/classifications/icd10/browse/2010/en#/P07 P07 - Disorders related to short gestation and low birth weight] in [[ICD-10]]</ref> Infants born with LBW have added health risks which require close management, often in a [[neonatal intensive care unit]] (NICU). They are also at increased risk for long-term health conditions which require follow-up over time.

==Classification==
Birth weight may be classified as:<ref name="titleeMedicine - Extremely Low Birth Weight Infant: Article by KN Siva Subramanian, MD">{{cite web |url=http://www.emedicine.com/ped/topic2784.htm |title=eMedicine - Extremely Low Birth Weight Infant: Article by KN Siva Subramanian, MD |access-date=2007-11-28 }}</ref>
* High birth weight ([[Large for gestational age|macrosomia]]): greater than {{convert|4200|g|lboz|abbr=on}}
* Normal weight (term delivery): {{convert|2500|–|4200|g|lboz|abbr=on}}
* Low birth weight: less than {{convert|2500|g|lboz|abbr=on}}
** Very low birth weight: less than {{convert|1500|g|lboz|abbr=on}}
** Extremely low birth weight: less than {{convert|1000|g|lboz|abbr=on}}

==Causes==
LBW is either caused by [[preterm birth]] (that is, a low [[Gestational age (obstetrics)|gestational age]] at birth, commonly defined as younger than 37 weeks of gestation) or the infant being [[small for gestational age]] (that is, a slow [[prenatal growth rate]]), or a combination of both.{{citation needed|date=December 2020}}

In general, risk factors in the mother that may contribute to low birth weight include young ages, multiple pregnancies, previous LBW infants, poor nutrition, heart disease or [[hypertension]], untreated [[celiac disease]], [[substance use disorder]], [[Alcohol use disorder|excessive alcohol use]], and insufficient [[prenatal care]]. It can also be caused by [[prelabor rupture of membranes]].<ref>{{Cite journal|last1=Rizzo|first1=Nicola|last2=Simonazzi|first2=Giuliana|last3=Curti|first3=Alessandra|date=2015-09-24|title=Obstetrical risk factors of ELBW|journal=Italian Journal of Pediatrics|volume=41|issue=Suppl 1|pages=A35|doi=10.1186/1824-7288-41-S1-A35|issn=1824-7288|pmc=4595176}}</ref> Environmental risk factors include smoking, lead exposure, and other types of air pollutions.<ref>{{cite web|url=http://www.umm.edu/pregnancy/000142.htm |title=Labor and delivery - Low Birth Weight |publisher=Umm.edu |date=2008-10-22 |access-date=2011-01-05 |archive-url=https://web.archive.org/web/20110820234857/http://www.umm.edu/pregnancy/000142.htm |archive-date=2011-08-20|url-status=dead}}</ref><ref name="TersigniCastellani2014">{{cite journal|last1=Tersigni|first1=C.|last2=Castellani|first2=R.|last3=de Waure|first3=C.|last4=Fattorossi|first4=A.|last5=De Spirito|first5=M.|last6=Gasbarrini|first6=A.|last7=Scambia|first7=G.|last8=Di Simone|first8=N.|title=Celiac disease and reproductive disorders: meta-analysis of epidemiologic associations and potential pathogenic mechanisms|journal=Human Reproduction Update|volume=20|issue=4|year=2014|pages=582–593|issn=1355-4786|doi=10.1093/humupd/dmu007|pmid=24619876|doi-access=free}}</ref><ref name=SacconeBerghella2015>{{cite journal|vauthors=Saccone G, Berghella V, Sarno L, Maruotti GM, Cetin I, Greco L, Khashan AS, McCarthy F, Martinelli D, Fortunato F, Martinelli P|title=Celiac disease and obstetric complications: a systematic review and metaanalysis |journal=Am J Obstet Gynecol |volume=214 |issue=2 |pages= 225–34|date= Oct 9, 2015 |pmid=26432464|doi=10.1016/j.ajog.2015.09.080}}</ref>

===Preterm birth===
{{Further|Preterm birth}}
The mechanism of preterm birth is heterogeneous and poorly understood. It may be tied to one or more of the following processes: premature fetal endocrine activation, intrauterine inflammation, over-distension of the uterus, and endometrial bleeding. A prominent risk factor for preterm birth is prior history of preterm delivery. However, there is no reliable protocol for screening and prevention of preterm birth.<ref name=Simham2007>
{{cite journal
|vauthors=Simhan HN, Caritis SN |year=2007
|title=Prevention of Preterm Delivery
|journal=[[New England Journal of Medicine]]
|volume=357
|issue=5 |pages=477–487
|pmid=17671256
|doi=10.1056/NEJMra050435
}}</ref>

===Small for gestational age===
{{Further|Small for gestational age}}
Infants born small for gestational age may be constitutionally small, with no associated pathologic process. Others have [[intrauterine growth restriction]] (IUGR) due to any of various pathologic processes. Babies with [[Chromosome abnormality|chromosomal abnormalities]] or other [[Birth defect|congenital anomalies]] may manifest IUGR as part of their syndrome. Problems with the [[placenta]] can prevent it from providing adequate oxygen and nutrients to the fetus, resulting in growth restriction. Infections during pregnancy that affect the fetus, such as [[rubella]], [[cytomegalovirus]], [[toxoplasmosis]], and [[syphilis]], may also affect the baby's weight.{{citation needed|date=December 2020}}

===Environmental factors===
[[Smoking and pregnancy|Maternal tobacco smoking]] doubles risk of LBW for the infant.<ref>{{cite journal |last1=Saygin Avsar |first1=Tuba |title=Health outcomes of smoking during pregnancy and the postpartum period: an umbrella review |journal=BMC Pregnancy and Childbirth |year=2021 |volume=21 |issue=1 |pages=43–49 |doi=10.1186/s12884-021-03729-1 |pmid=7995767 |s2cid=232360282 |url=https://pubmed.ncbi.nlm.nih.gov/33771100/}}</ref><ref>{{Cite journal|last=Knopik|first=Valerie S.|date=2009|title=Maternal smoking during pregnancy and child outcomes: real or spurious effect?|journal=Developmental Neuropsychology|volume=34|issue=1|pages=1–36|doi=10.1080/87565640802564366|issn=1532-6942|pmc=3581055|pmid=19142764}}</ref> More recently, [[Passive smoking|passive maternal smoking]] has been examined for possible effects on birth weight, and has been shown to increase risk of LBW by 16%.<ref>{{Cite journal|last1=Salmasi|first1=Giselle|last2=Grady|first2=Rosheen|last3=Jones|first3=Jennifer|last4=McDonald|first4=Sarah D.|last5=Knowledge Synthesis Group|date=2010|title=Environmental tobacco smoke exposure and perinatal outcomes: a systematic review and meta-analyses|journal=Acta Obstetricia et Gynecologica Scandinavica|volume=89|issue=4|pages=423–441|doi=10.3109/00016340903505748|issn=1600-0412|pmid=20085532|s2cid=9206564|doi-access=free}}</ref>

==== Air pollutants ====
The combustion products of solid fuel in developing countries can cause many adverse health issues in people. Because a majority of pregnant women in developing countries, where rate of LBW is high, are heavily exposed to [[indoor air quality|indoor air pollution]], increased relative risk translates into substantial population attributable risk of 21% of LBW.<ref>{{Cite journal|last1=Pope|first1=Daniel P.|last2=Mishra|first2=Vinod|last3=Thompson|first3=Lisa|last4=Siddiqui|first4=Amna Rehana|last5=Rehfuess|first5=Eva A.|last6=Weber|first6=Martin|last7=Bruce|first7=Nigel G.|date=2010|title=Risk of low birth weight and stillbirth associated with indoor air pollution from solid fuel use in developing countries|journal=Epidemiologic Reviews|volume=32|pages=70–81|doi=10.1093/epirev/mxq005|issn=1478-6729|pmid=20378629|doi-access=free}}</ref>

[[Particulates|Particulate matter]], a component of ambient [[air pollution]], is associated with increased risk of low birth weight.<ref>{{Cite web|last=EPA, OAR|first=US|date=2014-04-09|title=Criteria Air Pollutants|url=https://www.epa.gov/criteria-air-pollutants|access-date=2017-03-31|website=www.epa.gov|language=en}}</ref><ref>{{Cite journal|last1=Li|first1=Xiangyu|last2=Huang|first2=Shuqiong|last3=Jiao|first3=Anqi|last4=Yang|first4=Xuhao|last5=Yun|first5=Junfeng|last6=Wang|first6=Yuxin|last7=Xue|first7=Xiaowei|last8=Chu|first8=Yuanyuan|last9=Liu|first9=Feifei|last10=Liu|first10=Yisi|last11=Ren|first11=Meng|date=Aug 2017|title=Association between ambient fine particulate matter and preterm birth or term low birth weight: An updated systematic review and meta-analysis|url=https://pubmed.ncbi.nlm.nih.gov/28457735|journal=Environmental Pollution|volume=227|pages=596–605|doi=10.1016/j.envpol.2017.03.055|issn=1873-6424|pmid=28457735}}</ref> Because particulate matter is composed of extremely small particles, even nonvisible levels can be inhaled and present harm to the fetus.<ref>{{Cite web|title=CDC - Air Quality - Particle Pollution|url=https://www.cdc.gov/air/particulate_matter.html|access-date=2017-03-31|website=www.cdc.gov|language=en-us}}</ref> Particulate matter exposure can cause inflammation, oxidative stress, endocrine disruption, and impaired oxygen transport access to the placenta, all of which are mechanisms for heightening the risk of low birth weight.<ref>{{Cite journal|last1=Erickson|first1=Anders C.|last2=Arbour|first2=Laura|date=2014-11-26|title=The Shared Pathoetiological Effects of Particulate Air Pollution and the Social Environment on Fetal-Placental Development|journal=Journal of Environmental and Public Health|language=en|volume=2014|pages=901017|doi=10.1155/2014/901017|issn=1687-9805|pmc=4276595|pmid=25574176|doi-access=free}}</ref> To reduce exposure to particulate matter, pregnant women can monitor the EPA’s [[Air quality index|Air Quality Index]] and take personal precautionary measures such as reducing outdoor activity on low quality days, avoiding high-traffic roads/intersections, and/or wearing personal protective equipment (i.e., facial mask of industrial design). Indoor exposure to particulate matter can also be reduced through adequate ventilation, as well as use of clean heating and cooking methods.<ref>{{Cite web|date=2009-05-19|title=Particulate matter|url=http://www.epa.gov/oar/particlepollution/|url-status=dead|archive-url=https://web.archive.org/web/20090604201655/http://www.epa.gov/oar/particlepollution/|archive-date=2009-06-04|website=EPA}}</ref><ref>{{Cite web|author=US EPA National Center for Environmental Assessment, Research Triangle Park NC, Environmental Media Assessment Group|last2=Sacks|first2=Jason|title=2009 Final Report: Integrated Science Assessment for Particulate Matter|url=https://cfpub.epa.gov/ncea/risk/recordisplay.cfm?deid=216546|access-date=2017-03-31|website=cfpub.epa.gov|language=en}}</ref>

A correlation between maternal exposure to [[carbon monoxide]] (CO) and low birth weight has been reported that the effect on birth weight of increased ambient CO was as large as the effect of the mother smoking a pack of cigarettes per day during pregnancy.<ref>{{Cite journal|last=Lewtas|first=Joellen|date=Nov 2007|title=Air pollution combustion emissions: characterization of causative agents and mechanisms associated with cancer, reproductive, and cardiovascular effects|url=https://pubmed.ncbi.nlm.nih.gov/17951105|journal=Mutation Research|volume=636|issue=1–3|pages=95–133|doi=10.1016/j.mrrev.2007.08.003|issn=0027-5107|pmid=17951105}}</ref>
It has been revealed that adverse reproductive effects (e.g., risk for LBW) were correlated with maternal exposure to CO emissions in Eastern Europe and North America.<ref>{{cite journal|vauthors=Townsend CL, Maynard RL|date=Oct 2002|title=Effects on health of prolonged exposure to low concentrations of carbon monoxide|journal=Occup Environ Med|volume=59|issue=10|pages=708–11|doi=10.1136/oem.59.10.708|pmc=1740215|pmid=12356933}}</ref>
Mercury is a known toxic heavy metal that can harm fetal growth and health, and there has been evidence showing that exposure to mercury (via consumption of large [[oily fish]]) during pregnancy may be related to higher risks of LBW in the offspring.<ref>{{cite journal|vauthors=Gochfeld M, Burger J|date=Aug 2005|title=Good fish/bad fish: a composite benefit-risk by dose curve|journal=Neurotoxicology|volume=26|issue=4|pages=511–20|doi=10.1016/j.neuro.2004.12.010|pmid=15979722}}</ref>

==== Other exposures ====
Elevated blood lead levels in pregnant women, even those well below the US [[Centers for Disease Control and Prevention]]'s 10 ug/dL "level of concern", can cause [[miscarriage]], [[premature birth]], and LBW in the offspring.<ref>{{Cite journal|last1=Cleveland|first1=Lisa M.|last2=Minter|first2=Monica L.|last3=Cobb|first3=Kathleen A.|last4=Scott|first4=Anthony A.|last5=German|first5=Victor F.|date=Oct 2008|title=Lead hazards for pregnant women and children: part 1: immigrants and the poor shoulder most of the burden of lead exposure in this country. Part 1 of a two-part article details how exposure happens, whom it affects, and the harm it can do|url=https://pubmed.ncbi.nlm.nih.gov/18827541|journal=The American Journal of Nursing|volume=108|issue=10|pages=40–49; quiz 50|doi=10.1097/01.NAJ.0000337736.76730.66|issn=1538-7488|pmid=18827541}}</ref> Exposure of pregnant women to airplane noise was found to be associated with low birth weight via adverse effects on fetal growth.<ref>{{cite journal | author = Kawada T |date=Feb 2004 | title = The effect of noise on the health of children | journal = Journal of Nippon Medical School| volume = 71 | issue = 1| pages = 5–10 | doi=10.1272/jnms.71.5|pmid=15129589 | doi-access = free}}</ref> Prevalence of low birth weight in Japan is associated with radiation doses from the [[Fukushima Daiichi nuclear disaster|Fukushima accidents]] of March 2011.<ref>{{cite journal | author = Scherb H, Hayashi K |date=July 2020 | title = Spatiotemporal association of low birth weight with Cs-137 deposition at the prefecture level in Japan after the Fukushima nuclear power plant accidents: an analytical-ecologic epidemiological study| journal = Environmental Health |volume=19 |issue=1 |page=82 | doi= 10.1186/s12940-020-00630-w|pmid= 32646457|pmc=7346451 | doi-access = free}}</ref>

===Periodontal health===
Low birth weight, preterm birth and preeclampsia have been associated with maternal [[periodontal disease]], though the strength of the observed associations is inconsistent and varies according to the population studied, the means of periodontal assessment and the periodontal disease classification employed.<ref>{{cite journal|last1=Sanz|first1=M|title=Periodontitis and adverse pregnancy outcomes: consensus report of the Joint EFP/AAP Workshop on Periodontitis and Systemic Diseases|journal=J Periodontol|date=April 2013|volume=84|issue=4 suppl|pages=S164–9|doi=10.1902/jop.2013.1340016|pmid=23631576}}</ref> The risk of low birth weight can be reduced with treatment of the periodontal disease. This therapy is safe during pregnancy and reduces the inflammatory burden, thus decreasing risk for preterm birth and low birth weight.<ref>{{cite journal|last1=Shah|first1=Monali|title=Effect of nonsurgical periodontal therapy during gestation period on adverse pregnancy outcome: a systematic review|journal=J Matern Fetal Neonatal Med|date=November 2013|volume=26|issue=17|pages=1691–5|doi=10.3109/14767058.2013.799662|pmid=23617740|s2cid=23564952}}</ref>

== Management ==
=== Temperature regulation ===
[[File:Mom and Premature Baby at Kapiolani.jpg|thumb|Skin-to-skin contact with the mother can help with thermoregulation.]]
[[File:Mother_with_premature_baby_in_incubator.jpg|thumb|Low birth weight babies often spend time in a temperature-controlled [[Incubator (neonatal)|incubator]] due to their inability to maintain core body temperature.]]
LBW newborns are at increased risk of [[hypothermia]] due to decreased [[Brown adipose tissue|brown fat]] stores. Plastic wraps, heated pads, and skin-to-skin contact decrease risk of hypothermia immediately after delivery. One or more of these interventions may be employed, though combinations incur risk of [[hyperthermia]].<ref>{{Cite journal|last1=McCall|first1=Emma M.|last2=Alderdice|first2=Fiona|last3=Halliday|first3=Henry L.|last4=Vohra|first4=Sunita|last5=Johnston|first5=Linda|date=12 Feb 2018|title=Interventions to prevent hypothermia at birth in preterm and/or low birth weight infants|journal=The Cochrane Database of Systematic Reviews|volume=2018|issue=2|pages=CD004210|doi=10.1002/14651858.CD004210.pub5|issn=1469-493X|pmc=6491068|pmid=29431872}}</ref> Warmed [[Incubator (neonatal)|incubators]] in the NICU aid in thermoregulation for LBW infants.{{citation needed|date=December 2020}}

=== Fluid and electrolyte balance ===
Frequent clinical monitoring of volume status and checking of serum electrolytes (up to three times daily) is appropriate to prevent [[dehydration]], [[Hypervolemia|fluid overload]], and [[electrolyte imbalance]].<ref name=":02">{{Cite book|url=https://www.worldcat.org/oclc/775591575|title=Evidence-based handbook of neonatology.|date=2011|publisher=World Scientific|others=Oh, William.|isbn=978-981-4313-46-9|location=New Jersey|pages=267–290|oclc=775591575}}</ref> VLBW newborns have an increased body surface to weight ratio, increasing risk for insensible fluid losses and dehydration.<ref name=":0">{{Cite book|url=https://www.worldcat.org/oclc/775591575|title=Evidence-based handbook of neonatology.|date=2011|publisher=World Scientific|others=Oh, William.|isbn=978-981-4313-46-9|location=New Jersey|pages=291–315|oclc=775591575}}</ref> Humidified incubators and skin [[Moisturizer|emollients]] can lessen insensible fluid loss in VLBW newborns.<ref name=":02" /> However, fluid overloading is not benign; it is associated with increased risk of congestive heart failure, necrotizing enterocolitis, and mortality. A degree of fluid restriction mitigates these risks.<ref name=":02" />

VLBW newborns are at risk for electrolyte imbalances due to the relative immaturity of the [[nephron]]s in their [[kidney]]s. The kidneys are not equipped to handle large [[sodium]] loads. Therefore, if normal saline is given, the sodium level may become elevated, which may prompt the clinician to give more fluids. Sodium restriction has been shown to prevent fluid overload.<ref name=":02" /> [[Potassium]] must also be monitored carefully, as immature [[aldosterone]] sensitivity and [[Na+/K+-ATPase|sodium-potassium pumping]] increases risk for [[hyperkalemia]] and cardiac [[arrhythmia]]s.<ref name=":02" />

VLBW newborns are frequently found to have a persistently [[patent ductus arteriosus]] (PDA). If present, it is important to evaluate whether the PDA is causing increased circulatory volume, thus posing risk for heart failure. Signs of clinically significant PDA include widened pulse pressure and bounding pulses. In newborns with significant PDA, fluid restriction may avoid the need for surgical or medical therapy to close it.<ref name=":02" />

=== Approach to nutrition ===
As their gastrointestinal systems are typically unready for enteral feeds at the time of birth, VLBW infants require initial [[Parenteral nutrition|parenteral infusion]] of fluids, [[Nutrient|macronutrients]], [[vitamin]]s, and [[micronutrient]]s.<ref name=":0" />

==== Energy needs ====
Decreased activity compared to normal weight newborns may decrease energy requirements, while comorbidities such as [[bronchopulmonary dysplasia]] may increase them. Daily weight gain can reveal whether a VLBW newborn is receiving adequate calories. Growth of 21 g/kg/day, mirroring ''in utero'' growth, is a target for VLBW and ELBW neonates.<ref name=":0" />

==== Enteral sources ====
Upon transitioning to enteral nutrition, [[Breast milk|human milk]] is preferable to [[Infant formula|formula]] initially in VLBW newborns because it speeds up development of the intestinal barrier and thereby reduces risk of [[necrotizing enterocolitis]],<ref name=":0" /> with an [[Risk difference|absolute risk reduction]] of 4%.<ref>{{Cite journal|last1=Miller|first1=Jacqueline|last2=Tonkin|first2=Emma|last3=Damarell|first3=Raechel A.|last4=McPhee|first4=Andrew J.|last5=Suganuma|first5=Machiko|last6=Suganuma|first6=Hiroki|last7=Middleton|first7=Philippa F.|last8=Makrides|first8=Maria|last9=Collins|first9=Carmel T.|date=2018-05-31|title=A Systematic Review and Meta-Analysis of Human Milk Feeding and Morbidity in Very Low Birth Weight Infants|journal=Nutrients|volume=10|issue=6|page=707|doi=10.3390/nu10060707|issn=2072-6643|pmc=6024377|pmid=29857555|doi-access=free}}</ref> [[Human milk bank|Donor human milk]] and maternal expressed breast milk are both associated with this benefit.<ref name=":3">{{Cite journal|last1=Quigley|first1=Maria|last2=Embleton|first2=Nicholas D.|last3=McGuire|first3=William|date=July 19, 2019|title=Formula versus donor breast milk for feeding preterm or low birth weight infants|journal=The Cochrane Database of Systematic Reviews|volume=7|issue=7 |pages=CD002971|doi=10.1002/14651858.CD002971.pub5|issn=1469-493X|pmc=6640412|pmid=31322731}}</ref> One drawback of human milk is the imprecision in its calorie content. The fat content in human milk varies greatly among women; therefore, the energy content of human milk cannot be known as precisely as formula.<ref name=":0" /> Each time human milk is transferred between containers, some of the fat content may stick to the container, decreasing the energy content. Minimizing transfers of human milk between containers decreases the amount of energy loss.<ref name=":0" /> Formula is associated with greater linear growth and weight gain than donor breast milk in LBW infants.<ref name=":3" />

==== Individual nutrient considerations ====
VLBW newborns are at increased risk for [[hypoglycemia]] due to decreased energy reserves and large brain mass to body mass ratio. Hypoglycemia may be prevented by intravenous infusion of glucose, amino acids, and lipids.<ref name=":0" /> These patients are also at risk of [[hyperglycemia]] due to immature [[insulin]] secretion and sensitivity. However, insulin supplementation is not recommended due to the possible adverse effect of hypoglycemia, which is more dangerous.<ref name=":0" />

VLBW newborns have increased need for amino acids to mirror ''in utero'' nutrition. Daily protein intake above 3.0 g/kg is associated with improved weight gain for LBW infants.<ref>{{Cite journal|last1=Fenton|first1=Tanis R.|last2=Premji|first2=Shahirose S.|last3=Al-Wassia|first3=Heidi|last4=Sauve|first4=Reg S.|date=2014-04-21|title=Higher versus lower protein intake in formula-fed low birth weight infants|journal=The Cochrane Database of Systematic Reviews|volume=2014 |issue=4|pages=CD003959|doi=10.1002/14651858.CD003959.pub3|issn=1469-493X|pmc=7104240|pmid=24752987}}</ref> ELBW newborns may require as much as 4 g/kg/day of protein.<ref name=":0" />

Due to the limited [[solubility]] of [[calcium]] and [[phosphorus]] in parenteral infusions, VLBW infants receiving parenteral nutrition will be somewhat deficient of these elements and will require clinical monitoring for [[osteopenia]].<ref name=":0" />

=== Hematology ===
One Cochrane review showed administration of [[erythropoietin]] (EPO) decreases later need for [[blood transfusion]]s, and also is associated with protection against necrotizing enterocolitis and [[intraventricular hemorrhage]]. EPO is safe and does not increase risk of mortality or [[retinopathy of prematurity]].<ref>{{Cite journal|last1=Ohlsson|first1=Arne|last2=Aher|first2=Sanjay M.|date=2020-02-11|title=Early erythropoiesis-stimulating agents in preterm or low birth weight infants|journal=The Cochrane Database of Systematic Reviews|volume=2|issue=2 |pages=CD004863|doi=10.1002/14651858.CD004863.pub6|issn=1469-493X|pmc=7014351|pmid=32048730}}</ref>

==Prognosis==

=== Perinatal outcomes ===
[[File:Premature_infant_with_ventilator.jpg|thumb|Low birth weight infants may require respiratory support such as [[intubation]] and [[mechanical ventilation]] due to lung immaturity.]]LBW is closely associated with fetal and [[perinatal mortality]] and [[morbidity]], inhibited growth and cognitive development, and chronic diseases later in life. At the population level, the proportion of babies with a LBW is an indicator of a multifaceted public-health problem that includes long-term maternal malnutrition, ill health, hard work and poor health care in pregnancy. On an individual basis, LBW is an important predictor of newborn health and survival and is associated with higher risk of infant and childhood mortality.<ref>{{cite journal |vauthors=Stevens-Simon C, Orleans M |date=Sep 1999 | title = Low-birthweight prevention programs: the enigma of failure | journal = Birth | volume = 26 | issue = 3| pages = 184–91 | doi=10.1046/j.1523-536x.1999.00184.x|pmid=10655819 }}</ref>

Low birth weight constitutes as sixty to eighty percent of the [[infant mortality]] rate in developing countries. Infant mortality due to low birth weight is usually directly causal, stemming from other medical complications such as preterm birth, PPROM,<ref>{{Cite journal|last1=Kalikkot Thekkeveedu|first1=Renjithkumar|last2=Guaman|first2=Milenka Cuevas|last3=Shivanna|first3=Binoy|date=November 2017|title=Bronchopulmonary dysplasia: A review of pathogenesis and pathophysiology|journal=Respiratory Medicine|volume=132|pages=170–177|doi=10.1016/j.rmed.2017.10.014|issn=1532-3064|pmc=5729938|pmid=29229093}}</ref> poor maternal nutritional status, lack of [[prenatal care]], maternal sickness during pregnancy, and an unhygienic home environment.<ref name="Andrews">{{cite encyclopedia|last=Andrews|first=K.M.|author2=Brouillette, D.B |author3=Brouillette, R.T. |encyclopedia= Encyclopedia of Infant and Early Childhood Development|pages=343–359|year=2008|doi=10.1016/B978-012370877-9.00084-0|chapter=Mortality, Infant|isbn=9780123708779}}</ref>

=== Long term outcomes ===
[[Hyponatremia]] in the newborn period is associated with neurodevelopmental conditions such as spastic [[cerebral palsy]] and [[sensorineural hearing loss]]. Rapid correction of hyponatremia (faster than 0.4 mEq/L/hour) perinatally is also associated with neurodevelopmental adverse effects.<ref name=":02" /> Among VLBW children, risk for cognitive impairment is increased with lower birth weight, male sex, nonwhite ethnicity, and lower parental education level. There is no clear association between brain injury in the neonatal period and later cognitive impairment.<ref>{{Cite journal|last1=Linsell|first1=Louise|last2=Malouf|first2=Reem|last3=Morris|first3=Joan|last4=Kurinczuk|first4=Jennifer J.|last5=Marlow|first5=Neil|date=Dec 2015|title=Prognostic Factors for Poor Cognitive Development in Children Born Very Preterm or With Very Low Birth Weight: A Systematic Review|journal=JAMA Pediatrics|volume=169|issue=12|pages=1162–1172|doi=10.1001/jamapediatrics.2015.2175|issn=2168-6211|pmc=5122448|pmid=26457641}}</ref> Additionally, low birth weight has associations with cardiovascular diseases later in life, especially in cases of large increases in weight during childhood.<ref>Toemen L., De Jonge L.L., Gishti O., et al Longitudinal growth during fetal life and infancy and cardiovascular outcomes at school-age. J. Hypertens.. 2016;34(7):1396-1406. doi:10.1097/HJH.0000000000000947</ref><ref>Barker DJ, Osmond C, Forsen TJ, Kajantie E, Eriksson JG. Trajectoriesof growth among children who have coronary events as adults.N Engl JMed2005; 353:1802–1809.</ref><ref>Curhan GC, Willett WC, Rimm EB, Spiegelman D, Ascherio AL, Stamp-fer MJ. Birth weight and adult hypertension, diabetes mellitus, andobesity in US men.Circulation1996; 94:3246–3250</ref><ref>Osmond C, Barker DJ, Winter PD, Fall CH, Simmonds SJ. Early growthand death from cardiovascular disease in women.BMJ1993; 307:1519–1524.</ref>

Low birth rate is associated with [[schizoid personality disorder]].<ref>{{Cite web |url=https://jamanetwork.com/journals/jamapsychiatry/fullarticle/210877 |access-date=2023-05-03 |website=jamanetwork.com |doi=10.1001/archgenpsychiatry.2010.100}}</ref>

==Epidemiology==
The [[World Health Organization]] (WHO) estimates the worldwide prevalence of low birth weight at 15% as of 2014, and varies by region: Sub-Saharan Africa, 13%; South Asia, 28%; East Asia and the Pacific, 6%; Latin America and the Caribbean, 9%.<ref name=":1">{{Cite web|title=Global nutrition targets 2025: low birth weight policy brief|url=https://www.who.int/publications-detail-redirect/WHO-NMH-NHD-14.5|access-date=2020-11-04|website=www.who.int|language=en}}</ref> Aggregate prevalence of LBW in [[United Nations]]-designated Least Developed Countries<ref>{{Cite web|title=UNSD — Methodology: Standard country or area codes for statistical use (M49)|url=https://unstats.un.org/unsd/methodology/m49/|access-date=2020-11-04|website=unstats.un.org}}</ref> is 13%.<ref name=":1" /> The WHO has set a goal of reducing worldwide prevalence of LBW by 30% through public health interventions including improved prenatal care and women's education.<ref name=":1" />

In the United States, the [[Centers for Disease Control and Prevention]] (CDC) reports 313,752 LBW infants in 2018, for a prevalence of 8.28%.<ref>{{Cite web|date=2020-08-04|title=FastStats - Birthweight and Gestation|url=https://www.cdc.gov/nchs/fastats/birthweight.htm|access-date=2020-11-04|website=www.cdc.gov|language=en-us}}</ref> This is increased from an estimated 6.1% prevalence in 2011 by the [[Agency for Healthcare Research and Quality]] (AHRQ).<ref name=":2">Kowlessar N.M., Jiang H.J., and Steiner C. Hospital Stays for Newborns, 2011. HCUP Statistical Brief #163. October 2013. Agency for Healthcare Research and Quality, Rockville, MD. [http://www.hcup-us.ahrq.gov/reports/statbriefs/sb163.jsp] {{Webarchive|url=https://web.archive.org/web/20220818022705/https://www.hcup-us.ahrq.gov/reports/statbriefs/sb163.jsp|date=2022-08-18}}</ref> The CDC reported prevalence of VLBW at 1.38% in 2018, similar to the 2011 AHRQ estimate.<ref name=":2" />

==References==
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[[Category:Human body weight]]
[[Category:Disorders related to length of gestation and fetal growth]]
[[Category:Pediatrics]]
[[Category:Women's health]]

Low birth weight - Revision history

Ajay Kumar at 20:47, 29 August 2023