Editing SIDS (section)

===Pregnancy and infant factors===
SIDS rates decrease with increasing maternal age, with [[teenage pregnancy|teenage mothers]] at greatest risk.<ref name="sullivan">{{cite journal | vauthors = Sullivan FM, Barlow SM | title = Review of risk factors for sudden infant death syndrome | journal = Paediatric and Perinatal Epidemiology | volume = 15 | issue = 2 | pages = 144–200 | date = April 2001 | pmid = 11383580 | doi = 10.1046/j.1365-3016.2001.00330.x }}</ref> Delayed or inadequate [[prenatal care]] also increases risk.<ref name="sullivan"/> Low [[birth weight]] is a significant risk factor. In the United States from 1995 to 1998, the SIDS death rate for infants weighing 1000–1499 g was 2.89/1000, while for a birth weight of 3500–3999 g, it was only 0.51/1000.<ref name=wonder /><ref>{{cite journal | vauthors = Hunt CE | title = Small for gestational age infants and sudden infant death syndrome: a confluence of complex conditions | journal = Archives of Disease in Childhood. Fetal and Neonatal Edition | volume = 92 | issue = 6 | pages = F428–F429 | date = November 2007 | pmid = 17951549 | pmc = 2675383 | doi = 10.1136/adc.2006.112243 }}</ref> [[Premature birth]] increases the risk of SIDS death roughly fourfold.<ref name="sullivan"/><ref name="wonder"/> From 1995 to 1998, the U.S. SIDS rate for births at 37–39 weeks of [[gestation]] was 0.73/1000, while the SIDS rate for births at 28–31 weeks of gestation was 2.39/1000.<ref name="wonder"/>

[[Anemia]] has also been linked to SIDS<ref>{{cite journal | vauthors = Poets CF, Samuels MP, Wardrop CA, Picton-Jones E, Southall DP | title = Reduced haemoglobin levels in infants presenting with apparent life-threatening events--a retrospective investigation | journal = Acta Paediatrica | volume = 81 | issue = 4 | pages = 319–321 | date = April 1992 | pmid = 1606392 | doi = 10.1111/j.1651-2227.1992.tb12234.x | s2cid = 33298390 }}</ref> (however, per item 6 in the list of epidemiologic characteristics below, the extent of anemia cannot be evaluated at autopsy because an infant's total [[hemoglobin]] can only be measured during life).<ref>{{cite journal | vauthors = Giulian GG, Gilbert EF, Moss RL | title = Elevated fetal hemoglobin levels in sudden infant death syndrome | journal = The New England Journal of Medicine | volume = 316 | issue = 18 | pages = 1122–1126 | date = April 1987 | pmid = 2437454 | doi = 10.1056/NEJM198704303161804 }}</ref> SIDS incidence rises from zero at birth, is highest from two to four months of age, and declines toward zero after the infant's first year.<ref>{{cite journal | vauthors = Mage DT |title=A probability model for the age distribution of SIDS |journal=J Sudden Infant Death Syndrome Infant Mortal |volume=1 |pages=13–31 |year=1996}}</ref>