Human chorionic gonadotropin levels between 16 and 21 weeks of pregnancy and prediction of pre-eclampsia

Objective. To determine whether levels of beta human choriogonadotropin (β-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 β-hCG levels in the prediction of pre-eclampsia was evaluated. The likelihood ratios were calculated for different levels of β-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 β-hCG, the positive likelihood ratio was 11.1 in primigravidas and 6.9 in multigravidas. Conclusion. This study shows that measuring levels of β-hCG during the second trimester of pregnancy is useful in clinical practice to identify pregnant women who will develop pre-eclampsia.