title: Preterm birth time trends in Europe: a study of 19 countries.
abstract: OBJECTIVE
  To investigate time trends in preterm birth in Europe by multiplicity, gestational age, and onset of delivery.
  
  
  METHODS
  Analysis of aggregate data from routine sources.
  
  
  METHODS
  Nineteen European countries.
  
  
  METHODS
  Live births in 1996, 2000, 2004, and 2008.
  
  
  METHODS
  Annual risk ratios of preterm birth in each country were estimated with year as a continuous variable for all births and by subgroup using log-binomial regression models.
  
  
  METHODS
  Overall preterm birth rate and rate by multiplicity, gestational age group, and spontaneous versus non-spontaneous (induced or prelabour caesarean section) onset of labour.
  
  
  RESULTS
  Preterm birth rates rose in most countries, but the magnitude of these increases varied. Rises in the multiple birth rate as well as in the preterm birth rate for multiple births contributed to increases in the overall preterm birth rate. About half of countries experienced no change or decreases in the rates of singleton preterm birth. Where preterm birth rates rose, increases were no more prominent at 35-36 weeks of gestation than at 32-34 weeks of gestation. Variable trends were observed for spontaneous and non-spontaneous preterm births in the 13 countries with mode of onset data; increases were not solely attributed to non-spontaneous preterm births.
  
  
  CONCLUSIONS
  There was a wide variation in preterm birth trends in European countries. Many countries maintained or reduced rates of singleton preterm birth over the past 15 years, challenging a widespread belief that rising rates are the norm. Understanding these cross-country differences could inform strategies for the prevention of preterm birth.
authors.affiliation: INSERM, UMRS 953, Epidemiological Research Unit on Perinatal and Women's and Children's Health, Paris, France; UPMC, Paris, France.
authors.forename: J
authors.initials: J
authors.lastname: Zeitlin
authors.forename: K
authors.initials: K
authors.lastname: Szamotulska
authors.forename: N
authors.initials: N
authors.lastname: Drewniak
authors.forename: A D
authors.initials: AD
authors.lastname: Mohangoo
authors.forename: J
authors.initials: J
authors.lastname: Chalmers
authors.forename: L
authors.initials: L
authors.lastname: Sakkeus
authors.forename: L
authors.initials: L
authors.lastname: Irgens
authors.forename: M
authors.initials: M
authors.lastname: Gatt
authors.forename: M
authors.initials: M
authors.lastname: Gissler
authors.forename: B
authors.initials: B
authors.lastname: Blondel
mesh_terms: D005060:Europe / Q000453:epidemiology; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D050498:Live Birth / Q000453:epidemiology; D009099:Multiple Birth Offspring / Q000706:statistics & numerical data; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology*
keywords: Europe; indicated preterm births; multiple births; preterm births; time trends