LH-monitors are most often NOT accurate in women with infertility for a number of reasons:
See the ClearBlue Monitor leaflet, attention to the section entitled "Further Information" here:
The P+3 progesterone test was developed by Dr. Thomas Hilgers after 30+ years of research. He published a study in 2020 which indicated that a progesterone level drawn on P+3 was a good marker to determine that ovulation has passed.
The P+3 test can be used if a woman is lacking confidence using the CREIGHTON MODEL FertilityCare™ System (CrMS), such as in the case where she may have a "continuous mucus pattern". This test is also valuable for a woman who has a serious reason to avoid a pregnancy, such as during menopause.
Table 1 below represents the P+3 progesterone interpretation used by many NaPro providers.
- 0.0–1.0 ng/mL: You have either not yet ovulated or you are within twenty-four hours of starting your period.
- 1.1–2.3 ng/mL: You are in the midst of ovulating. Repeating another level in forty-eight hours should clarify your situation. You should consider yourself fertile.
- 2.4–3.0 ng/mL: You have almost for certain ovulated. To be absolutely sure, a repeat level in twenty-four to forty-eight hours will clarify it. You are most likely not fertile until your next period starts.
- 3.1 ng/mL or >: You have ovulated, and you are naturally infertile until the start of your next menstrual period.
PLEASE NOTE: This test is not for medical, diagnostic or therapeutic purposes. It is for assisting you in identifying your natural state of post-ovulation (post-Peak) infertility and is intended for use in association with the CREIGHTON MODEL FertilityCare™System.
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. Full article here: