Resolving speculations of methodological inadequacies in the standardized protocol for characterizing women's fertility: Comment on Lobmaier and Bachofner (2018)

Abstract

Lobmaier and Bachofner (2018) suggest a series of methodological practices to increase the accuracy and reliability of determining a woman's fertile window, claiming the standardized protocol for characterizing women's fertility by Blake et al. (2016) is inadequate. These practices include observing participants for purportedly fertile sessions a considerable time before the LH surge, and using salivary ferning and cervical mucus evaluation as real-time measures of current fertility. Here I explain that Lobmaier and Bachofner's (2018) recommendations decrease rather than increase the likelihood of observing women during peak fertility. I also summarize the pertinent literature on salivary ferning and cervical mucus evaluations, showing that neither method has sufficient sensitivity and specificity to characterize peak fertility. Using meta-analytic data of 10K menstrual cycles, I then show that the protocol provided by Blake et al. (2016) recruits women when conception probability is at its peak and is statistically higher than the window recommended by Lobmaier and Bachofner (2018).