A prospective, randomized study of the chorionic gonadotropin-time relationship in early gestation: clinical implications.
OBJECTIVE
To investigate the hCG-time relationship in early pregnancy.


METHODS
Prospective, randomized study.


METHODS
Pregnant human volunteers in a university-based clinical research environment.


METHODS
Normal pregnant women with viable singleton pregnancies, conceived spontaneously or after ovulation induction.


METHODS
Vaginal ultrasound was performed, and blood samples were obtained for hormone parameters between 20 and 30 days after conception. The timing of the tests was determined by random assignment using sealed envelopes.


METHODS
Serum hCG.


RESULTS
The log hCG-time relationship was linear, both during the first 20 days and between 20 and 30 days after conception. The inclusion of a quadratic term in either regression was not statistically significant. The slopes of the two regression lines were also not statistically different.


CONCLUSIONS
For practical purposes, the hCG-time relationship in early pregnancy can be treated as log-linear, but short sampling intervals should be used if doubling times are to be calculated from paired samples.
Department of Obstetrics and Gynecology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, New Brunswick.
N
N
Kadar
M
M
Bohrer
E
E
Kemman
R
R
Shelden
D006063:Chorionic Gonadotropin / Q000097:blood*; D005260:Female; D006801:Humans; D009994:Osmolar Concentration; D011247:Pregnancy / Q000097:blood*; D011261:Pregnancy Trimester, First; D011446:Prospective Studies; D012044:Regression Analysis; D013048:Specimen Handling; D013997:Time Factors
D006063:Chorionic Gonadotropin