title: The comparative clinical course of pregnant and non-pregnant women hospitalised with influenza A(H1N1)pdm09 infection.
abstract: BACKGROUND
  The Influenza Clinical Information Network (FLU-CIN) was established to gather detailed clinical and epidemiological information about patients with laboratory confirmed A(H1N1)pdm09 infection in UK hospitals. This report focuses on the clinical course and outcomes of infection in pregnancy.
  
  
  METHODS
  A standardised data extraction form was used to obtain detailed clinical information from hospital case notes and electronic records, for patients with PCR-confirmed A(H1N1)pdm09 infection admitted to 13 sentinel hospitals in five clinical 'hubs' and a further 62 non-sentinel hospitals, between 11th May 2009 and 31st January 2010.Outcomes were compared for pregnant and non-pregnant women aged 15-44 years, using univariate and multivariable techniques.
  
  
  RESULTS
  Of the 395 women aged 15-44 years, 82 (21%) were pregnant; 73 (89%) in the second or third trimester. Pregnant women were significantly less likely to exhibit severe respiratory distress at initial assessment (OR = 0.49 (95% CI: 0.30-0.82)), require supplemental oxygen on admission (OR = 0.40 (95% CI: 0.20-0.80)), or have underlying co-morbidities (p-trend <0.001). However, they were equally likely to be admitted to high dependency (Level 2) or intensive care (Level 3) and/or to die, after adjustment for potential confounders (adj. OR = 0.93 (95% CI: 0.46-1.92). Of 11 pregnant women needing Level 2/3 care, 10 required mechanical ventilation and three died.
  
  
  CONCLUSIONS
  Since the expected prevalence of pregnancy in the source population was 6%, our data suggest that pregnancy greatly increased the likelihood of hospital admission with A(H1N1)pdm09. Pregnant women were less likely than non-pregnant women to have respiratory distress on admission, but severe outcomes were equally likely in both groups.
authors.affiliation: Health Protection Research Group, Division of Epidemiology and Public Health, University of Nottingham, Clinical Sciences Building, Nottingham City Hospital, Nottingham, United Kingdom. Gayle.Dolan@hpa.org.uk
authors.forename: Gayle P
authors.initials: GP
authors.lastname: Dolan
authors.forename: Puja R
authors.initials: PR
authors.lastname: Myles
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Brett
authors.forename: Joanne E
authors.initials: JE
authors.lastname: Enstone
authors.forename: Robert C
authors.initials: RC
authors.lastname: Read
authors.forename: Peter J M
authors.initials: PJ
authors.lastname: Openshaw
authors.forename: Malcolm G
authors.initials: MG
authors.lastname: Semple
authors.forename: Wei Shen
authors.initials: WS
authors.lastname: Lim
authors.forename: Bruce L
authors.initials: BL
authors.lastname: Taylor
authors.forename: James
authors.initials: J
authors.lastname: McMenamin
authors.forename: Karl G
authors.initials: KG
authors.lastname: Nicholson
authors.forename: Barbara
authors.initials: B
authors.lastname: Bannister
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Nguyen-Van-Tam
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006760:Hospitalization; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000150:complications / Q000453:epidemiology* / Q000503:physiopathology* / Q000628:therapy; D058873:Pandemics; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology* / Q000628:therapy; D015995:Prevalence; D012128:Respiratory Distress Syndrome / Q000453:epidemiology / Q000209:etiology / Q000628:therapy; D012720:Severity of Illness Index; D006113:United Kingdom / Q000453:epidemiology