title: HbA1c as screening for gestational diabetes mellitus in women with polycystic ovary syndrome.
abstract: BACKGROUND
  Gestational diabetes mellitus (GDM) is associated with adverse pregnancy outcomes such as preeclampsia and macrosomia. Women with polycystic ovary syndrome (PCOS) are at increased risk of developing GDM. Today, GDM is diagnosed by oral glucose tolerance test (OGTT), a rather cumbersome test for the women and health care system. The objectives of this study were to investigate whether HbA1c in first trimester of pregnancy could be used as a screening test for GDM in first trimester and throughout pregnancy in order to reduce the number of OGTTs, and whether it could predict preeclampsia and macrosomia in women with PCOS.
  
  
  METHODS
  Post hoc analyses of data from 228 women from a prospective, randomised, multicenter study comparing metformin to placebo from first trimester to delivery. Fasting and 2-h plasma glucose were measured during a 75 g OGTT in first trimester, gestational week 19 and 32 as well as fasting plasma glucose in gestational week 36. GDM was diagnosed by WHO criteria from 1999 in first trimester and throughout pregnancy and by modified IADPSG criteria (i.e. lacking the 1-h plasma glucose value) in first trimester. The diagnostic accuracy was assessed by logistic regression and ROC curve analysis.
  
  
  RESULTS
  The area under the ROC curve for first trimester HbA1c for screening of GDM diagnosed by WHO criteria in first trimester was 0.60 (95 % CI 0.44-0.75) and 0.56 (95 % CI 0.47-0.65) for GDM diagnosed throughout pregnancy. Only 2.2 % (95 % CI 0.7-5.1 %) of the participants could have avoided OGTT. HbA1c was not statistically significantly associated with GDM diagnosed by modified IADPSG criteria in first trimester. However, first trimester HbA1c was statistically significantly associated with preeclampsia. Both HbA1c and GDM by WHO criteria in first trimester, but not by IADPSG, were negatively associated with birth weight.
  
  
  CONCLUSIONS
  First trimester HbA1c can not be used to exclude or predict GDM in women with PCOS, but it might be better to predict preeclampsia than the GDM diagnosis.
authors.affiliation: Department of Clinical Chemistry, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway. ingridhov@gmail.com.|Department of Cancer Research and Molecular Medicine, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway. ingridhov@gmail.com.
authors.forename: Ingrid Hov
authors.initials: IH
authors.lastname: Odsæter
authors.affiliation: Department of Clinical Chemistry, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway. arne.aasberg@stolav.no.
authors.forename: Arne
authors.initials: A
authors.lastname: Åsberg
authors.affiliation: Department of Obstetrics and Gynecology, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway. eszter.vanky@ntnu.no.|Department of Laboratory Medicine, Children's and Women's Health, Trondheim, Norway. eszter.vanky@ntnu.no.
authors.forename: Eszter
authors.initials: E
authors.lastname: Vanky
authors.affiliation: Department of Endocrinology, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway. sven.carlsen@ntnu.no.|Department of Cancer Research and Molecular Medicine, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway. sven.carlsen@ntnu.no.|Unit for Applied Clinical Research, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway. sven.carlsen@ntnu.no.
authors.forename: Sven Magnus
authors.initials: SM
authors.lastname: Carlsen
mesh_terms: D000328:Adult; D015331:Cohort Studies; D016640:Diabetes, Gestational / Q000175:diagnosis* / Q000378:metabolism; D005260:Female; D005320:Fetal Macrosomia / Q000453:epidemiology / Q000378:metabolism*; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D016015:Logistic Models; D011085:Polycystic Ovary Syndrome / Q000150:complications / Q000378:metabolism*; D011225:Pre-Eclampsia / Q000453:epidemiology / Q000378:metabolism*; D011247:Pregnancy; D011296:Prenatal Diagnosis; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human