Chorionic gonadotropin in the blood and urine during early pregnancy

Abstract

Since the development and use of biologic tests for pregnancy, there has been a considerable accumulation of uncoordinated data recording the time of appearance of chorionic gonadotropin in the urine and serum of women after fertilization. The appearance of this hormone has been variously recorded at “a few days after implantation of the ovum”4, 13 to “two weeks after the expected but missed menstrual period.”3, 5, 14, 23 Browne and Venning dated the appearance of chorionic gonadotropin in the urine of women after fertilization at ten to thirteen days after the elevation of urinary pituitary gonadotropin associated with ovulation.6, 8, 9, 11, 12, 13, 21 With such a paucity of accurate reports dealing with the time of the first appearance of chorionic gonadotropin in the urine and serum of pregnant women, there has been an accompanying lack of serial quantitative surveys of hormone levels during early pregnancy. In the few recorded cases,6, 8, 16, 17, 20, 24, 25 serial assays were begun at forty to fifty days after the first day of the last normal menstrual period. Thus, there is a void in knowledge of the hormone levels between fertilization and the forty-day to fifty-day interval.The purpose of this investigation is to establish the time of first appearance of human chorionic gonadotropin in the urine and serum of women after fertilization and to determine quantitatively the concentrations of hormone throughout early pregnancy. In contrast to most previous reports, in which values are expressed in terms of one or another animal unit, this report will present values expressed in terms of international units. Although it is not possible to compare such values with previous ones, or for that matter to make comparisons among the previously reported values in terms of absolute amounts, the fluctuation curve of hormonal excretion can be compared relatively.