Cervical consistency in women of fertile age measured with a new mechanical instrument.

Abstract

Abstract. A new instrument designed for the measurement of the cervical consistency has been used in an investigation of 100 non‐pregnant and 49 pregnant women. The instrument consists of a mechanism for control of the force used, enabling the examiner to exert the desired pressure on the uterine cervix, and another mechanism for recording the tissue consistency. Both mechanisms were calibrated before each measurement. During measurement the instrument was held horizontally and pressed lightly against the anterior lip of the cervix. The cervical consistency is characterized by the angle α between the walls of the impressed surface recorded on the indicator mechanism of the instrument. The highest values of α are found in the softest tissues. The results showed a highly significant inter‐individual difference (F= 7.355 > P, 90) between 30 of the non‐pregnant patients who had from 3 to 6 measurements performed in different menstrual cycles (intraclass correlation r = 0.612 ± 0.083). Variation about the individual mean is only 1/F—13.6%. In the non‐pregnant cervix a rise in the mean measured values was noted during the first phase of the menstrual cycle. The mean values for non‐pregnant women using a combined oral contraceptive were slightly higher. In normal pregnancies the measurements showed significantly different values in three different time intervals. The highest values were found near term. Within a few weeks after parturition the values fell and approached the “normal values” for non‐pregnant women.