Gamete intrafallopian transfer and plasma chorionic gonadotropin dynamics: evidence of a delayed appearance.

The purpose of this study was to compare early human chorionic gonadotropin secretion in two groups of pregnancies. These pregnancies were obtained, in one group, during a natural cycle, while, in the other group, they resulted from gamete intrafallopian transfers performed in hyperstimulated cycles. A logarithmic regression analysis was chosen to allow statistical comparison of serial plasmatic evaluation as hormone determinations were obtained, among patients, at different postovulatory days. The regression lines of the two groups of patients presented similar slopes. The unpaired t test performed on calculated data for 3 different days constantly revealed significantly higher levels (P less than 0.005) of natural vs stimulated cycles; thus a different origin on the x axis (days of the luteal phase) is deduced. These findings support the possibility of a delay in the appearance of human chorionic hormone in the patients undergoing gamete intrafallopian transfer technique.