title: Nationwide registry-based ecological analysis of Q fever incidence and pregnancy outcome during an outbreak in the Netherlands.
abstract: OBJECTIVE
  Whether areas affected by Q fever during a large outbreak (2008-2010) had higher rates of adverse pregnancy outcomes than areas not affected by Q fever.
  
  
  METHODS
  Nationwide registry-based ecological study.
  
  
  METHODS
  Pregnant women in areas affected and not affected by Q fever in the Netherlands, 2003-2004 and 2008-2010.
  
  
  METHODS
  Index group (N=58,737): pregnant women in 307 areas with more than two Q fever notifications. Reference group (N=310,635): pregnant women in 921 areas without Q fever notifications. As a baseline, pregnant women in index and reference areas in the years 2003-2004 were also included in the reference group to estimate the effect of Q fever in 2008-2010, and not the already existing differences before the outbreak.
  
  
  METHODS
  Preterm delivery, small for gestational age, perinatal mortality.
  
  
  RESULTS
  In 2008-2010, there was no association between residing in a Q fever-affected area and both preterm delivery (adjusted OR 1.01 (95% CI 0.94 to 1.08)), and perinatal mortality (adjusted OR 0.87 (95% CI 0.72 to 1.05)). In contrast, we found a weak significant association between residing in a Q fever-affected area in 2008-2010 and small for gestational age (adjusted OR 1.06 (95% CI 1.01 to 1.12)), with a population-attributable fraction of 0.70% (95% CI 0.07% to 1.34%). We observed no dose-response relation for this outcome with increasing Q fever notifications, and we did not find a stronger association for women who were in their first trimester of pregnancy during the months of high human Q fever incidence.
  
  
  CONCLUSIONS
  This study found a weak association between residing in a Q fever-affected area and the pregnancy outcome small for gestational age. Early detection of infection would require mass screening of pregnant women; this does not seem to be justified considering these results, and the uncertainties about its efficacy and the adverse effects of antibiotic treatment.
authors: Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands.
authors: Marit M A
authors: MM
authors: de Lange
authors: The Netherlands Perinatal Registry, Utrecht, the Netherlands.
authors: Chantal W P M
authors: CW
authors: Hukkelhoven
authors: Department of Obstetrics and Gynaecology, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands.
authors: Janna M
authors: JM
authors: Munster
authors: Department of Medical Microbiology and Infection Control, Jeroen Bosch Hospital, 's-Hertogenbosch, the Netherlands.
authors: Peter M
authors: PM
authors: Schneeberger
authors: Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands.
authors: Wim
authors: W
authors: van der Hoek
mesh_terms: D000328:Adult; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D009426:Netherlands / Q000453:epidemiology; D054238:Perinatal Mortality; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology*; D011256:Pregnancy Outcome; D047928:Premature Birth / Q000453:epidemiology; D011778:Q Fever / Q000453:epidemiology*; D012042:Registries; D055815:Young Adult
keywords: Epidemiology < INFECTIOUS DISEASES; OBSTETRICS; Public health < INFECTIOUS DISEASES