The Identification of Postovulation Infertility with the Measurement of Early Luteal Phase (Peak Day +3) Progesterone Production
Objective: 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.
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.
Hilgers TW. The Identification of Postovulation Infertility with the Measurement of Early Luteal Phase (Peak Day +3) Progesterone Production. Linacre Q. 2020 Feb;87(1):78-84. doi: 10.1177/0024363919885551. Epub 2019 Nov 13. PMID: 32431450; PMCID: PMC7016439.