2ND-TRIMESTER LEVELS OF MATERNAL URINARY GONADOTROPIN PEPTIDE IN DOWN-SYNDROME PREGNANCY

Urinary gonadotropin peptide (UGP; beta-core fragment), a major metabo lite of human chorionic gonadotropin (hCG), was shown recently to be m arkedly elevated in Down syndrome pregnancy between 19 and 22 weeks of gestation. To confirm and extend this finding, we obtained maternal u rine and matching maternal serum samples from 14 cases of Down syndrom e and six other aneuploidies between 17 and 21 weeks of gestation. UGP was measured in all these samples and in 91 singleton control urines. Results were corrected for urinary creatinine level and expressed as multiples of the control median (MOM). hCG levels were assayed in all serum samples from the cases and compared with previously established reference values. The median UGP level in Down syndrome cases was 5.34 MOM (range 2.71-12.57); 88 per cent of the values were above the 95th centile of control levels after modelling. The median maternal serum hCG level for the same cases was 2.20 MOM (range 0.84-3.40); 36 per ce nt of the values were above the 95th centile. The level of UGP in ever y case including all other aneuploidies was higher than the comparable maternal serum hCG level. Elevated UGP measurements are strongly asso ciated with fetal Down syndrome during the second trimester and could contribute to improved Down syndrome screening protocols that are more accessible and less expensive than are currently available.