Cervicovaginal peroxidases: markers of the fertile period.

The specific activity of guaiacol peroxidase was measured daily in human cervical mucus, vaginal fluids, and saliva during 45 cycles in 31 women. Also determined were basal body temperatures and serum hormones (luteinizing hormone [LH], estradiol, progesterone). The guaiacol peroxidase was extracted with 0.5 M CaCl2 and thus may be a different peroxidase from that obtained by noncalcium extraction procedures. The guaiacol peroxidase specific activity did not vary in the saliva during the cycle but fell sharply in the cervical mucus and vaginal fluid four to five days before the ovulation time, estimated by the LH peak, and rose again one to two days after ovulation. Anovulatory cycles did not show the midcycle drop in guaiacol peroxidase. Growth curve analysis gave excellent fitting of the guaiacol peroxidase data to a polynominal model. These data suggest that cervicovaginal guaiacol peroxidase may be clinically useful in detecting the fertile period for population control and for infertility treatment.