title: False-positive 1-hour glucose challenge test and adverse perinatal outcomes.
abstract: OBJECTIVE
  To determine whether a false-positive 1-hour glucose challenge test (GCT) is associated with perinatal complications.
  
  
  METHODS
  We performed a retrospective cohort study of 1825 eligible pregnant women among a cohort of 1998 patients. Patients were screened for gestational diabetes mellitus (GDM) with the 1-hour 50-g GCT at 24-28 gestational weeks. A false-positive GCT was defined as a result greater than or equal to 135 mg/dL followed by a normal 3-hour glucose tolerance test (GTT). We compared the negative GCT and false-positive GCT cohorts for a composite perinatal outcome variable that included fetal macrosomia, antenatal death, shoulder dystocia, chorioamnionitis, preeclampsia, intensive care nursery admission, and postpartum endometritis. Secondary outcomes included cesarean delivery and each component variable of the composite. Unadjusted, stratified, and multiple logistic regression analyses were used to investigate the association between a false-positive GCT and the development of perinatal complications.
  
  
  RESULTS
  We identified 164 patients with a false-positive GCT and 50 patients with GDM. The false-positive GCT cohort on average was older, of higher parity, had a higher body mass index, and more frequently had chronic hypertension, sickle cell trait, and elevated midtrimester human chorionic gonadotropin levels. The false-positive GCT cohort more frequently had adverse perinatal outcomes, including the composite perinatal outcome (odds ratio [OR] 5.96, 95% confidence interval[CI]1.47,24.16), macrosomia greater than 4500 g (OR 3.66, 95% CI 1.30, 10.32), antenatal death (OR 4.61, 95% CI 0.77, 27.48), shoulder dystocia (OR 2.85, 95% CI 1.25, 6.51), endometritis (OR 2.18, 95% CI 1.03, 4.63), and cesarean delivery (OR 1.76, 95% CI 0.99, 3.14).
  
  
  CONCLUSIONS
  A false-positive GCT is an independent risk factor for adverse perinatal outcomes.
authors.affiliation: Center for Clinical Epidemiology and Biostatistics and Department of Obstetrics and Gynecology, University of Pennsylvania Health System, Philadelphia, Pennsylvania 19104, USA. dstamilio@obgyn.upenn.edu
authors.forename: David M
authors.initials: DM
authors.lastname: Stamilio
authors.forename: Tandy
authors.initials: T
authors.lastname: Olsen
authors.forename: Sarah
authors.initials: S
authors.lastname: Ratcliffe
authors.forename: Harish M
authors.initials: HM
authors.lastname: Sehdev
authors.forename: George A
authors.initials: GA
authors.lastname: Macones
mesh_terms: D000328:Adult; D015992:Body Mass Index; D015331:Cohort Studies; D016640:Diabetes, Gestational / Q000175:diagnosis*; D005189:False Positive Reactions; D005260:Female; D005951:Glucose Tolerance Test / Q000379:methods*; D006801:Humans; D008499:Medical Records; D007744:Obstetric Labor Complications / Q000453:epidemiology* / Q000209:etiology; D010414:Pennsylvania / Q000453:epidemiology; D011247:Pregnancy; D011256:Pregnancy Outcome; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors