title: Work as a nurse and a midwife and adverse pregnancy outcomes: a Finnish nationwide population-based study.
abstract: OBJECTIVE
  To assess whether work as a nurse and a midwife during pregnancy increases the risk of adverse pregnancy outcomes.
  
  
  METHODS
  We identified from the 1990-2006 Finnish Medical Birth Registry all singleton births to nurses (n=109,542), midwives (n=3,009), and teachers (n=23,454) (referents). The main outcomes were sexual differentiation, low and high birth weight, preterm and postterm delivery, small and large for gestational age, and perinatal death.
  
  
  RESULTS
  The prevalence of low birth weight (2.9% vs. 2.5%), preterm delivery (4.4% vs. 4.1%), postterm delivery (4.7% vs. 4.1%), small for gestational age (1.8% vs. 1.4%), perinatal death (0.45% vs. 0.41%) and stillbirth (0.30% vs. 0.25%) was higher among the newborns of nurses than those of teachers. The adjusted odds ratio (OR) from generalized estimating equations was 1.17 (95% confidence interval [CI] 1.07-1.26) for low birth weight, 1.09 (95% CI 1.02-1.16) for preterm delivery, 1.11 (95% CI 1.03-1.18) for postterm delivery, 1.17 (95% CI 1.05-1.30) for small for gestational age, 1.12 (95% CI 0.90-1.35) for perinatal death, and 1.27 (95% CI 0.98-1.56) for stillbirth. For midwives, the risk of small for gestational age (OR=1.25, 95% CI 0.95-1.55) was elevated, but the 95% CI included unity. There was no substantial difference in the sex distribution.
  
  
  CONCLUSIONS
  This study provides evidence that work as a nurse may reduce fetal growth and duration of pregnancy. The inference is based on the newborns of teachers as the reference group. However, the prevalence of most of the outcomes was higher among the newborns of all other working women combined than in the newborns of both nurses and teachers.
authors.affiliation: Institute of Occupational and Environmental Medicine, University of Birmingham, United Kingdom.
authors.forename: Reginald
authors.initials: R
authors.lastname: Quansah
authors.forename: Mika
authors.initials: M
authors.lastname: Gissler
authors.forename: Jouni J K
authors.initials: JJ
authors.lastname: Jaakkola
mesh_terms: D000328:Adult; D005178:Faculty / Q000706:statistics & numerical data; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D007231:Infant, Newborn; D008880:Midwifery / Q000706:statistics & numerical data*; D009726:Nurses / Q000706:statistics & numerical data*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology* / Q000451:nursing*; D011256:Pregnancy Outcome / Q000453:epidemiology*; D015995:Prevalence; D012042:Registries; D014931:Women, Working / Q000706:statistics & numerical data*; D055815:Young Adult