Elevated second-trimester maternal urine free beta-human chorionic gonadotropin levels in Asian pregnancies with fetal chromosomal abnormalities

Objectives: To investigate the second trimester maternal urine free beta-human chorionic gonadotropin (hCG) levels of chromosomally abnormal pregnancies in Asians. Methods: Free beta-hCG levels were analyzed from the urine samples of 110 control and 17 chromosomally abnormal pregnancies, including 11 cases of Down syndrome, 1 case of trisomy 18, and other chromosomal abnormalities (one mosaic deletion and 4 translocations) from the second trimester of pregnancy. Results were normalized to urine creatinine (Cr) concentration and converted to the multiple of the median (MOM) level for the appropriate gestation. Gestational age of all cases was determined by ultrasound parameters. Results: The median free beta-hCG MOM levels of Down syndrome (4.02 MOM) and other chromosomally abnormal pregnancies (2.03 MOM) are significantly higher than that of normal pregnancies (0.99 MOM) (p = 0.002 and p = 0.024, respectively). Nine of 11 (81.8%) Down syndrome cases, one trisomy 18 case, and 2 of 5 (40%) other chromosomally abnormal cases would be expected to be above the 95th centile of the control values (2.95 MOM cut-off). Conclusion: Urine free beta-hCG could be a potential and useful marker in the detection of fetal Down syndrome and other chromosomal abnormalities in Asians.