title: Adverse effects of screening for gestational diabetes: a prospective cohort study in Toronto, Canada.
abstract: OBJECTIVE
  To investigate the adverse effects associated with a false positive 50 g glucose challenge test for gestational diabetes mellitus (GDM).
  
  
  METHODS
  Consecutive women attending a prenatal registration clinic at a large community hospital in suburban Toronto, Canada.
  
  
  METHODS
  Prospective cohort study of women between 12 and 24 weeks' gestation with no previous history of diabetes mellitus or GDM. Main outcome measures included anxiety (Spielberger's State-Trait Anxiety Inventory), depression (Centers for Epidemiologic Studies Depression Scale), perceived maternal health, and concern about health of the newborn.
  
  
  RESULTS
  Among 2564 eligible subjects, there were 897 subjects with complete data at enrollment and at 32 weeks' gestation, including 88 who had false positive glucose challenge test results. At 32 weeks, only 20% (95% confidence limits 11%, 28%) of women with false positive glucose challenge test results rated their health as excellent, compared with 38% (35%, 42%) of those having negative results and those not tested (P = 0.001). These results were sustained at 36 weeks. There was no association between glucose challenge test result and the change in anxiety (P = 0.57), depression (P = 0.09) or concern about health of the newborn (P = 0.91) between baseline and 32 weeks' gestation, nor were these associations found at 36 weeks.
  
  
  CONCLUSIONS
  False positive glucose challenge test results are about six times more likely than true positive results in the general population. Pregnant women with false positive GDM screening results experience a significant decline in their perception of their own health. These adverse effects should be taken into account when deciding about a policy of screening all pregnant women for gestational diabetes.
authors.affiliation: Public Health Branch, Ontario Ministry of Health, Canada.
authors.forename: D
authors.initials: D
authors.lastname: Kerbel
authors.forename: R
authors.initials: R
authors.lastname: Glazier
authors.forename: S
authors.initials: S
authors.lastname: Holzapfel
authors.forename: M
authors.initials: M
authors.lastname: Yeung
authors.forename: S
authors.initials: S
authors.lastname: Lofsky
mesh_terms: D002170:Canada; D015331:Cohort Studies; D003920:Diabetes Mellitus / Q000151:congenital / Q000517:prevention & control*; D005189:False Positive Reactions; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D015997:Neonatal Screening / Q000009:adverse effects*; D011247:Pregnancy