Shindler J S, Haworth K, Axon A, Bardsley W G, Tindall V R, Laing I
J Reprod Fertil. 1977 Nov;51(2):413-7. doi: 10.1530/jrf.0.0510413.
Fourteen healthy women were screened for the following parameters throughout one complete menstrual cycle: levels of urinary oestrogens and pregnanediol; levels of plasma and urinary gonadotrophins; and pH, protein content and levels of peroxidase in the cervical mucus. It was found that concentrations of peroxidase in the cervical mucus were not a reliable index of ovulation.