Objective. To study the pH of cervical mucus on the eve of physiological spontaneous labor to identify indicators of the pregnant woman’s body readiness to labor.

Materials and methods. The study included 50 pregnant women hospitalized for delivery to the Clinical Maternity Hospital of Minsk Region expected the labor favorable outcome for the mother and the fetus. The pH of the cervical mucus was measured using indicator test strips for determining pH and a laboratory I-160.1 MP ionomer. The statistical analysis of the obtained results was performed using the STATISTICA 8.0 application software package.

Results. There was no statistically significant difference between the pH values of frozen and unfrozen mucus samples as well as between the values obtained by the ionomer and the test strips. When the pH of the cervical mucus changed during the prenatal adjustment the highest pH values of the cervical mucus were found during the last two days before the delivery being 6.3 [5.0—7.0] and 7.5 [6.5—8.7].

Conclusion. Determining the pH of cervical mucus using indicator test strips was accepted to be a more acceptable method for the clinical practice. For the first time, it was found that the pH of cervical mucus changed on the eve of a physiological spontaneous labor. The highest pH values of cervical mucus were observed during the last two days before the physiological labor.