The temporal relationship between vaginal fluid volumes obtained with the Rovumeter vaginal aspirator and the fertile phase of the cycle.

ABSTRACT

PIP: Natural family planning methods rely on clinical indicators to determine the onset of ovulation and the fertile period. Cervico-vaginal fluid volumes are known to change in different cycle phases. In 1985 a graduated vaginal aspirator, the Rovumeter, was developed, which enabled women to collect their own cervico-vaginal fluid. To test the feasibility of daily measurement of cervico-vaginal fluid volume as a method of natural family planning, 6 fertile women recorded for 13 cycles their daily cervico-vaginal fluid volumes. They also recorded, for comparison, urinary luteinizing hormone levels measured with a dipstick, cervical mucus changes, basal body temperatures, and changes in the uterine cervix. Follicular diameter measurements were tracked ultrasonically. Volumetric changes in the cervico-vaginal fluid corresponding to the fertile and infertile phases were detected in all 13 cycles, and they displayed a more precise relationship with the start of the fertile period than either mucus or cervix changes. The signal for the start of the fertile period is the 1st day of appreciable rise of the cervico-vaginal fluid, and the day of fall is the 1st of 2 consecutive days on which the cervico-vaginal fluid is equal or less than the threshold. The method is inexpensive and accurate and should offer a new objective approach to natural family planning.