Free alpha-subunit of human chorionic gonadotropin in Down syndrome.

Abstract

The purpose of this study was to evaluate the potential value of maternal serum free alpha-subunit of human chorionic gonadotropin concentrations in discriminating between pregnancies associated with Down syndrome and normal matched controls. Maternal serum concentrations were evaluated in 36 cases of fetal Down syndrome and compared with concentrations in 180 control unaffected pregnancies within the gestational age range 16 to 20 weeks matched for maternal age, gestational age, and storage duration. The results of the study indicate that free alpha-subunit of human chorionic gonadotropin concentrations in the Down syndrome group were not significantly different from those in the unaffected group (median multiple of the median: for Down syndrome group, 0.991; for unaffected group, 1.000). Caution is urged in the interpretation of published data; a case for using this subunit of human chorionic gonadotropin in Down syndrome screening protocols in the second trimester is not yet proved.