title: Human chorionic gonadotropin levels between 16 and 21 weeks of pregnancy and prediction of pre-eclampsia.
abstract: OBJECTIVE
  To determine whether levels of beta human choriogonadotropin (beta-hCG) during the second trimester are a predictor of pre-eclampsia.
  
  
  METHODS
  A prospective study of 784 women was conducted between their 16th and 20th week of pregnancy. Primigravidas and multigravidas were analyzed separately, and the cutoff point was determined using a receiver operating characteristic curve. The accuracy of beta-hCG levels in the prediction of pre-eclampsia was evaluated. The likelihood ratios were calculated for different levels of beta-hCG in both groups.
  
  
  RESULTS
  Pre-eclampsia prevalence was 7.1% among primigravidas and 4.6% among multigravidas. The cutoff concentration was 2.0 MoM in both groups. For primigravidas and multigravidas, respectively, the area below the curve was 0.96 and 0.95; sensitivity was 88.5% and 100%; specificity was 92.0% and 85.6%; positive predictive value was 0.46 and 0.25; and negative predictive value was 0.99 and 1.0. With a cutoff concentration of 2.0 MoM of beta-hCG, the positive likelihood ratio was 11.1 in primigravidas and 6.9 in multigravidas.
  
  
  CONCLUSIONS
  This study shows that measuring levels of beta-hCG during the second trimester of pregnancy is useful in clinical practice to identify pregnant women who will develop pre-eclampsia.
authors.affiliation: Unidad de Investigación Clínica, Torreón, Coahuila, México. joserioz@yahoo.com
authors.forename: J
authors.initials: J
authors.lastname: Roiz-Hernández
authors.forename: J
authors.initials: J
authors.lastname: de J Cabello-Martínez
authors.forename: M
authors.initials: M
authors.lastname: Fernández-Mejía
mesh_terms: D000293:Adolescent; D000328:Adult; D006063:Chorionic Gonadotropin / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D005865:Gestational Age; D020073:Gravidity; D006801:Humans; D011225:Pre-Eclampsia / Q000097:blood / Q000175:diagnosis*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second / Q000097:blood*; D015995:Prevalence; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity
chemical_list: D006063:Chorionic Gonadotropin