Fehring, R. J. (2002). Accuracy of the peak day of cervical mucus as a biological marker of fertility. Contraception, 66(4), 231–235.
Key Results
Ninety-three of the 108 cycles had both an identified PD and LH surge. Data charts showed that 97.8% of the PD fell within +/-4 days of the estimated day of ovulation. Use of a standardized mucus cycle scoring system indicated that the peak in cervical mucus ratings was highest on the day of the LH surge.
Conclusion
Self-determination of the PD of cervical mucus is a very accurate means of determining peak fertility and a fairly accurate means of determining the day of ovulation and the beginning of the end of the fertile time.