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Disappearance of exogenously administered human chorionic gonadotropin
M D Damewood1, W Shen, H A Zacur
1Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
Fertility and Sterility
|September 1, 1989
Summary
Human chorionic gonadotropin (hCG) levels after injection persist for up to 14 days. Expressing daily hCG as a fraction of the 36-hour level (hCG0) normalizes variations for accurate pregnancy testing in fertility treatments.
Area of Science:
- Reproductive Endocrinology
- Clinical Chemistry
Background:
- Exogenous human chorionic gonadotropin (hCG) is frequently used in assisted reproductive technologies for final oocyte maturation.
- Accurate monitoring of hCG levels is crucial for interpreting pregnancy tests and managing ovarian stimulation protocols.
Purpose of the Study:
- To characterize the pharmacokinetic profile of intramuscular hCG administration.
- To establish a method for normalizing hCG concentrations to account for individual variability.
Main Methods:
- Serum hCG concentrations were measured in 34 patients undergoing ovarian stimulation for in vitro fertilization.
- An immunoenzymetric assay was used for quantitative hCG detection.
- Daily hCG levels were expressed as a fractional distribution of the concentration at 36 hours post-injection (hCG0).
Main Results:
- Detectable serum hCG levels persisted for up to 14 days post-injection.
- Expressing hCG levels as a fraction of hCG0 significantly minimized individual variations.
- In nonpregnant patients, less than 10% of the hCG0 value remained by day 10.
- The exponential disappearance rate of hCG yielded a mean half-life of 2.32 days.
Conclusions:
- Normalization of hCG levels using the hCG0 reference provides a more reliable method for interpreting quantitative pregnancy tests.
- These findings are critical for optimizing the timing and accuracy of pregnancy testing in patients receiving exogenous hCG during fertility treatments.
- Understanding hCG pharmacokinetics aids in managing ovarian stimulation protocols and improving IVF outcomes.