Objective: To develop an assay for vaginal CA125 and determine if vaginal levels correlate with the phase of the menstrual cycle.
Study design: Fifteen women through a total of 20 ovulatory cycles obtained daily vaginal swabs for assay. Sampling began within the first 3 days after menses in and continued into the luteal phase. The subjects eluted the cotton swab tips in vials containing a standard volume of water. At the completion of each cycle the vial concentrations of CA125 were measured with the Siemens IMMULITE 2000. These "Qvaginal" levels of CA125 were indexed to the first day of positive urine luteinizing hormone signal, day 0.
Results: Qvaginal CA125 levels ranged from background (< 1 U/mL) to 5,740 U/mL and followed a periodic pattern: low during the early preovulatory phase, a maximum generally during day -4 to day +1, and low during the luteal phase. Qvaginal CA125 levels during the interval of presumptive fertility, day -4 to day +1, were statistically higher than levels during the preovulatory interval ending at day -5 and the postovulatory interval starting at day +2 (p value < 0.02).
Conclusions: The vaginal swab assay for CA125 can potentially track the phase of the ovulatory cycle and therefore may have applications for fertility awareness and diagnosis of reproductive disorders.