Human cervical mucus. IV. Viscoelasticity and sperm penetrability during the ovulatory menstrual cycle.

Quantitative viscoelastic and sperm penetration measurements were made on individual human cervial mucus samples collected from several ovulatory menstrual cycles. An inverse relationship was found to exist between these two mucus properties, with peak penetrability seen during the ovulatory phase of the cycle when viscoelasticity was lowest. Limited sperm penetration was also observed with follicular phase mucus. When mucus was collected three times daily, the first sample of the day showed reduced pH values and elevated percentage of nondialyzable solids (NDS) and viscoelastcity. Rates of mucus production were calculated for two cycles; the highest rate was seen during the ovulatory phase, with the follicular and luteal phases showing approximately 50% and 30% of this rate, respectively. Limited disparities were noted between midcycle changes in percentage of mucus NDS and viscoelasticity and in blood levels of total estrogens.