The Identification of Postovulation Infertility with the Measurement of Early Luteal Phase (Peak Day +3) Progesterone Production

This study reports on 632 cycles from 105 women who were using the CREIGHTON MODEL FertilityCare™ System to avoid pregnancy and had either a serious reason to avoid pregnancy or some degree of a lack of confidence. A progesterone level was drawn on the third day after the Peak Day as they were charting, and if the progesterone level was 2.3 ng/mL or greater, then ovulation was determined to have passed. If the level was greater than 3.0 ng/mL, this indicated that an absolute period of infertility had begun. In these cases, no pregnancies were observed. In the 27 cycles in which a specific follow-up relative to pregnancy could not be definitively determined, the progesterone levels in all cases were 2.3 ng/mL or greater with 23 of the 27 cycles being 3.1 ng/mL or greater. It is highly unlikely that any of those became pregnant as well. These cycles were collected over thirteen years (2004-2016). Two case presentations are also a part of this article of two families in which the couples had very serious reasons to avoid pregnancy. In these two couples, each of the women was multi-gravid and had no evidence of subfertility or infertility. They used the family planning progesterone level (the Peak Day +3 progesterone level) for a total of 167 cycles over a number of years successfully without a subsequent pregnancy.

Summary: This article presents a thirteen-year effort to evaluate the serum progesterone level on the third day after the Peak Day as observed by women charting the CREIGHTON MODEL FertilityCare™ System. It is known that the Peak Day is associated with ovulation, and if the progesterone reaches a certain level, then an absolute period of infertility should follow. In fact, this is what this study reflects.