Hourly human chorionic gonadotropin secretion profiles during the peri-implantation period of successful pregnancies.

Objective: To characterize the hourly profiles of hCG secretion in blood during conceptive cycles that ended in successful pregnancy.

Design: Prospective study.

Setting: University fertility clinic and research laboratories.

Patient(s): Healthy spontaneously ovulating women with regular menses, no history of infertility, and either no male partner or an azospermic partner.

Intervention(s): Frequent blood samples were collected daily from 11 spontaneously ovulating women during 11 cycles of artifical insemination with donor semen. The concentrations of hCG, LH, and FSH were measured in the blood by immunoassay.

Main Outcome Measure(s): The concentration of hCG in the frequent blood samples and the rate that the concentration of hCG changed during the period of frequent sampling.

Result(s): For the conceptive cycles resulting in successful pregnancies analyzed, hourly hCG concentrations were observed to increase in a consistent nonpulsatile manner.

Conclusion(s): These data provide the first characterization of the hourly secretion profile of hCG in early pregnancy as well as provide further evidence that individual daily blood samples are sufficient for the accurate assessment of pregnancy.