Urinary concentrations of beta core fragment of hCG throughout pregnancy.
OBJECTIVE
We sought to determine a reference range for urinary immunoreactive beta core fragment of hCG (beta C-hCG) in pregnancy, the ratio between beta C-hCG and intact hCG, and the earliest detectable rise of beta C-hCG in urine.


METHODS
Urine was obtained from 741 pregnant women between 6-41 weeks' gestation, as well as from women undergoing donor insemination with timed ovulation peaks.


RESULTS
The beta core fragment of hCG reached a maximum between 8-15 weeks, with a decrease between 20-29 weeks. The molar ratio of beta C-hCG to intact hCG was always greater than 1.


CONCLUSIONS
In pregnancy, beta C-hCG concentrations increase in the urine in parallel to intact hCG but at a higher molar ratio, suggesting either placental production of beta C-hCG or enhanced metabolism of hCG to beta C-hCG in peripheral organs.
de Medeiros
S F
SF
Department of Obstetrics and Gynecology, University of Adelaide, Queen Elizabeth Hospital, Woodville, South Australia.
Amato
F
F
Matthews
C D
CD
Norman
R J
RJ
D006063:Chorionic Gonadotropin / Q000652:urine*; D018997:Chorionic Gonadotropin, beta Subunit, Human; D003404:Creatinine / Q000652:urine; D005260:Female; D006801:Humans; D010446:Peptide Fragments / Q000652:urine*; D011247:Pregnancy / Q000652:urine*; D012016:Reference Values
D006063:Chorionic Gonadotropin; D018997:Chorionic Gonadotropin, beta Subunit, Human; D010446:Peptide Fragments; D003404:Creatinine