title: Epidemiological Evidence for a Decreasing Incidence of Neonatal Abstinence Syndrome, 2000-11.
abstract: BACKGROUND
  This study analyses the incidence of Neonatal Abstinence Syndrome (NAS) in a large geographically defined population in Australia.
  
  
  METHODS
  Database linkage analysis of all births between 2000 and 2011 in New South Wales (NSW), Australia. The diagnosis of NAS was derived from hospital coding P96.1, 'Neonatal withdrawal symptoms from maternal use of drugs of addiction'. Temporal trends were studied by comparing epoch 1 (2000-05) with epoch 2 (2006-11). The relationship with changes in maternal factors was further analysed.
  
  
  RESULTS
  The NAS was coded in 3842 of 1 022 263 live born infants (0.38%). NAS incidence peaked at 5.07 per 1000 live births in 2002, decreasing to 3.18 in 2011 and was negatively correlated with maternal age (r = -0.7). The rate of NAS in epoch 2 (3.4 per 1000 births, 95% CI 3.28, 3.58) was significantly lower than in epoch 1 (4.1 per 1000 births, 95% CI 3.96, 4.33). Epoch 2 mothers were significantly older (mean 29.8 years vs. 28.3 years), less likely to be multiparous (OR 0.7, 95% CI 0.6, 0.9) or smoke (OR 0.4, 95% CI 0.4, 0.5). They were more likely to engage in antenatal care earlier (mean first visit: 14.1 vs. 18.9 weeks). Most infants (~80%) were born at term (>37 weeks gestation).
  
  
  CONCLUSIONS
  The incidence of NAS as a discharge diagnosis has decreased in our population since 2002. Mothers are also older and engaging earlier in prenatal care. Whether these changes alter NAS presentation and diagnosis or whether pregnant women are using drugs that do not cause typical NAS (e.g. amphetamines) is uncertain and requires further study.
authors: School of Women's and Children's Heath, University of New South Wales, Kensington, NSW, Australia.
authors: Hannah
authors: H
authors: Uebel
authors: Illawarra Health and Medical Research Institute and Graduate School of Medicine, The University of Wollongong, Wollongong, NSW, Australia.|Department of Paediatrics, The Wollongong Hospital, Wollongong, NSW, Australia.
authors: Ian M
authors: IM
authors: Wright
authors: National Drug and Alcohol Research Centre, University of New South Wales, Sydney, NSW, Australia.
authors: Lucy
authors: L
authors: Burns
authors: School of Women's and Children's Heath, University of New South Wales, Kensington, NSW, Australia.|Centre for Big Data Research in Health, University of New South Wales, Sydney, NSW, Australia.
authors: Lisa
authors: L
authors: Hilder
authors: Perinatal Services Network, Westmead, NSW, Australia.
authors: Barbara
authors: B
authors: Bajuk
authors: National Drug and Alcohol Research Centre, University of New South Wales, Sydney, NSW, Australia.
authors: Courtney
authors: C
authors: Breen
authors: Department of Neonatology, The Canberra Hospital, Garran, ACT, Australia.|Faculty of Medicine, the Australian National University, Deakin, ACT, Australia.
authors: Mohamed E
authors: ME
authors: Abdel-Latif
authors: School of Women's and Children's Heath, University of New South Wales, Kensington, NSW, Australia.|Department of Newborn Care, Royal Hospital for Women, Randwick, NSW, Australia.
authors: Meredith
authors: M
authors: Ward
authors: School of Women's and Children's Heath, University of New South Wales, Kensington, NSW, Australia.|Sydney Local Health District, Sydney, NSW, Australia.|Ingham Institute of Applied Medicine, University of New South Wales, Liverpool, NSW, Australia.
authors: John
authors: J
authors: Eastwood
authors: School of Women's and Children's Heath, University of New South Wales, Kensington, NSW, Australia.|Sydney Children's Hospital, Randwick, NSW, Australia.
authors: John M
authors: JM
authors: Feller
authors: The Langton Centre, Surry Hills, NSW, Australia.
authors: Janet
authors: J
authors: Falconer
authors: The Langton Centre, Surry Hills, NSW, Australia.
authors: Sara
authors: S
authors: Clews
authors: School of Women's and Children's Heath, University of New South Wales, Kensington, NSW, Australia.|Department of Newborn Care, Royal Hospital for Women, Randwick, NSW, Australia.|Ingham Institute of Applied Medicine, University of New South Wales, Liverpool, NSW, Australia.
authors: Ju Lee
authors: JL
authors: Oei
mesh_terms: D000293:Adolescent; D000328:Adult; D001315:Australia / Q000453:epidemiology; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006760:Hospitalization / Q000639:trends*; D006801:Humans; D015994:Incidence; D007223:Infant; D007226:Infant Mortality / Q000639:trends*; D007231:Infant, Newborn; D016247:Information Storage and Retrieval; D008297:Male; D009357:Neonatal Abstinence Syndrome / Q000453:epidemiology* / Q000209:etiology; D009517:New South Wales / Q000453:epidemiology; D009293:Opioid-Related Disorders / Q000150:complications / Q000453:epidemiology*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology* / Q000209:etiology
keywords: incidence; linkage; neonatal abstinence syndrome