3.2. Cycle Data and Ovulation Detection
The 30 participants contributed 84 menstrual cycles. The average cycle length was 28.82 days (range 24–38, SD 3.62). The LH surge was detected in 94% of the cycles by the CBFM, 82% by the Premom LH test strips, and 95% by EAH LH test strips. The correlation of the Premom peak day with the CBFM first peak was r = 0.99; The estimated day of ovulation for the CBFM was defined as the second peak day on the CBFM. 