FERTILITY AND STERILITY
Vol. 54, No.5, November 1990
Copyright© 1990 The American Fertility Society
Printed on acid-free paper in U.S.A.
Further observations on the doubling time of human chorionic gonadotropin in early asymptomatic pregnancies
Nicholas Kadar, M.D.* Martin Freedman, M.D. Millicent Zacher, D.O. Department of Obstetrics and Gynecology, Albert Einstein Medical Center, Philadelphia, Pennsylvania
The doubling time (DT) of human chorionic gonadotropin (hCG) in serum was investigated retrospectively using serial serum hCG values that had been obtained from asymptomatic pregnant women with a prior history of infertility. The DT of hCG did not increase significantly as pregnancy advanced during the period in gestation when the serum hCG concentration was 10,000 miU/mL (IRP). Again, only one set of data points was used for each patient, and gestational age was expressed as days after the presumed date of ovulation. The DT of hCG was also calculated for each patient with a normal IUP who had had their serum hCG concentrations determined on at least two occasions within 2 to 5 days, and who had initial hCG concentrations< 6,000 miU/mL (IRP). The DTof hCG was calculated as: hCG DT = log.2/slope and the "slope" of the log hCG-time curve was calculated as log.(hCG 2 /hCG 1 ) -;- sampling interval (where hCG 1 was the first, and hCG 2 was the second serum hCG concentration), using the first two available hCG values for each patient. Patients who had normal IUPs were then categorized into three groups as defined by Pittaway et al., 1 and the mean hCG DTs for the three groups were compared by a one-way ANOVA. The groups are defined as follows: group I, H 1 and H 2 < 1,200; group II, 1,200 < H 1 and H 2 < 6,000; group Ill, H 1 < 1,200 and 1,200 < H 2 6,000, where H 1 and H 2 are the first Fertility and Sterility
and second hCG concentrations, and all numerical values refer to miU /mL (IRP). Two successive DTs of hCG were calculated for each patient with a normal IUP who had serum hCG concentrations measured on three or more occasions, and at least three values were