Human chorionic gonadotropin and plasma protein-A in alpha 0-thalassemia pregnancies

Abstract

OBJECTIVE: Maternal serum free β-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A) have been used effectively in the screening of Down syndrome in the first trimester. In this study, we aim to measure the value of first-trimester maternal serum free β-hCG and PAPP-A as predictors of homozygous α-thalassemia-affected pregnancies. METHODS: Free β-hCG and PAPP-A concentrations were measured in stored maternal serum samples obtained at 12 weeks of gestation from 22 women with fetuses affected by homozygous α-thalassemia and from 436 controls matched for maternal age, ethnicity, and weight, as well as gestation at blood sampling. RESULTS: Maternal serum concentration of free β-hCG was significantly increased in women with pregnancies affected by homozygous α-thalassemia than in controls (P=.001). Concentrations of PAPP-A did not differ between the cases affected by homozygous α-thalassemia and the controls (P=.652). CONCLUSION: Pregnancies affected by homozygous α-thalassemia are associated with increased maternal serum free β-hCG at 11-14 weeks of gestation. This serum analyte alone may not be clinically useful as a predictor of pregnancies affected by homozygous α-thalassemia. However, the absence of ultrasound features of fetal anemia and hydropic changes, together with normal maternal serum free β-hCG and PAPP-A in the first trimester, will be reassuring signs of normality for fetuses at risk of homozygous α-thalassemia and, hence, enable women to avoid invasive tests in unaffected pregnancies. © 2006 by The American College of Obstetricians and Gynecologists. Published by Lippincott Williams & Wilkins.