title: Medication use during pregnancy, gestational age and date of delivery: agreement between maternal self-reports and health database information in a cohort.
abstract: BACKGROUND
  Health databases are a promising resource for epidemiological studies on medications safety during pregnancy. The reliability of information on medications exposure and pregnancy timing is a key methodological issue. This study (a) compared maternal self-reports and database information on medication use, gestational age, date of delivery; (b) quantified the degree of agreement between sources; (c) assessed predictors of agreement.
  
  
  METHODS
  Pregnant women recruited in a prenatal clinic in Friuli Venezia Giulia (FVG) region, Italy, from 2007 to 2009, completed a questionnaire inquiring on medication use during pregnancy, gestational age and date of delivery. Redeemed prescriptions and birth certificate records were extracted from regional databases through record linkage. Percent agreement, Kappa coefficient, prevalence and bias-adjusted Kappa (PABAK) were calculated. Odds Ratio (OR), with 95% confidence interval (95% CI), of ≥ 1 agreement was calculated through unconditional logistic regression.
  
  
  RESULTS
  The cohort included 767 women, 39.8% reported medication use, and 70.5% were dispensed at least one medication. Kappa and PABAK indicated almost perfect to substantial agreement for antihypertensive medications (Kappa 0.86, PABAK 0.99), thyroid hormones (0.88, 0.98), antiepileptic medications (1.00, 1.00), antithrombotic agents (0.70, 0.96). PABAK value was greater than Kappa for medications such as insulin (Kappa 0.50, PABAK 0.99), antihistamines for systemic use (0.50, 0.99), progestogens (0.28, 0.79), and antibiotics (0.12, 0.63). Adjusted OR was 0.48 (95% CI 0.26; 0.90) in ex- vs. never smokers, 0.64 (0.38; 1.08) in < high school vs. university, 1.55 (1.01; 2.37) in women with comorbidities, 2.25 (1.19; 4.26) in those aged 40+ vs. 30-34 years. Gestational age matched exactly in 85.2% and date of delivery in 99.5%.
  
  
  CONCLUSIONS
  For selected medications used for chronic conditions, the agreement between self-reports and dispensing data was high. For medications with low to very low prevalence of use, PABAK provides a more reliable measure of agreement. Maternal reports and dispensing data are complementary to each other to increase the reliability of information on the use of medications during pregnancy. Birth certificates provide reliable data on the timing of pregnancy. FVG health databases are a valuable source of data for pregnancy research.
authors.affiliation: Institute of Hygiene and Clinical Epidemiology, University Hospital of Udine, Via Colugna 50, 33100, Udine, Italy. federica.pisa@uniud.it.|Department of Medical and Biological Sciences, University of Udine, Udine, Italy. federica.pisa@uniud.it.
authors.forename: Federica Edith
authors.initials: FE
authors.lastname: Pisa
authors.affiliation: Department of Medical and Biological Sciences, University of Udine, Udine, Italy. anica.casetta@uniud.it.
authors.forename: Anica
authors.initials: A
authors.lastname: Casetta
authors.affiliation: Direzione Centrale Salute, Integrazione Socio Sanitaria e Politiche Sociali, Regione Friuli Venezia Giulia, Udine, Italy. elena.clagnan@regione.fvg.it.
authors.forename: Elena
authors.initials: E
authors.lastname: Clagnan
authors.affiliation: INSIEL SpA, Udine, Italy. elisa.michelesio@insiel.it.
authors.forename: Elisa
authors.initials: E
authors.lastname: Michelesio
authors.affiliation: Scientific Direction, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy. vecchi@burlo.trieste.it.
authors.forename: Liza
authors.initials: L
authors.lastname: Vecchi Brumatti
authors.affiliation: Institute of Hygiene and Clinical Epidemiology, University Hospital of Udine, Via Colugna 50, 33100, Udine, Italy. fabio.barbone@uniud.it.|Department of Medical and Biological Sciences, University of Udine, Udine, Italy. fabio.barbone@uniud.it.|Department of Medicine, University of Trieste, Trieste, Italy. fabio.barbone@uniud.it.
authors.forename: Fabio
authors.initials: F
authors.lastname: Barbone
mesh_terms: D000328:Adult; D001719:Birth Certificates; D015897:Comorbidity; D016208:Databases, Factual; D036861:Delivery, Obstetric; D011307:Drug Prescriptions / Q000145:classification / Q000706:statistics & numerical data*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007558:Italy; D016015:Logistic Models; D008499:Medical Records; D016017:Odds Ratio; D011247:Pregnancy; D011295:Prenatal Care; D011996:Records; D015203:Reproducibility of Results; D057566:Self Report; D055815:Young Adult