Validity of retrospectively reported behaviors during the periconception window.

OBJECTIVE: To assess the validity of retrospectively reported maternal behaviors while attempting pregnancy. STUDY
DESIGN: Participants in a prospective pregnancy cohort study with periconception enrollment were queried about use of cigarettes, alcohol, vitamins and caffeine and the consumption of sport fish while attempting pregnancy. Prospective longitudinal data reported in daily diaries (gold standard) were compared with data obtained a decade later using a self-administered questionnaire. Agreement was assessed by percent agreement and Kappa coefficients.
RESULTS: Among the 82 participating women, percent agreement ranged from 54-74% for the 5 behaviors. Validity was highest for smoking (Kappa = 0.43, 95% confidence interval [CI]: 0.22, 0.65) followed by fish consumption (Kappa = 0.32, 95% CI: 0.09, 0.55), caffeine (Kappa = 0.21, 95% CI: 0.09, 0.51) and alcohol (Kappa = 0.20, 95% CI: 0.08, 0.33). There were no systematic differences in agreement by time to pregnancy or pregnancy outcome. Associations between smoking and alcohol consumption and pregnancy outcomes were highly sensitive to the levels of misclassification observed in this study.
CONCLUSION: Validity was poor to moderate for the 5 behaviors, though higher for more regular behaviors such as smoking and caffeine consumption. The potential for misreporting of periconception behaviors can affect inferences, and thus efforts to capture information prospectively should be promoted.