Measurements of consistency on the portio vaginalis of the uterus employing a new apparatus to measure compliance

Abstract

A new apparatus was developed to measure the consistency of the portio vaginalis of the uterus in terms of compliance. Periodically changing pressures were applied to the portio anc the volume changes thus induced were measured electrically. Compliance was calculated frorr the measurements. Compliance in 38 non-pregnant, 82 pregnant and 7 puerperal women were measured with this apparatus. The following results were obtained:1) Compliance in non-pregnant women was 5.7±1.5 (×10-12 m5/N). The menstrual cycle had no influences upon compliance. Compliance in women in their thirties was lower than those in their twenties.2) Compliance in pregnant women gradually increased as the gestational week advanced. The increase accelerated considerably toward the onset of labor, beginning 15 days before the onset. Compliance in 5-15 weeks was 7.5±2.4, 9.9±3.2 in 16-27 weeks and 12.5±6.7 in 28-41 weeks. In the pregnant women the levels of serum estradiol, estriol and progesterone correlated with compliance.3) Compliance 25-34 days after delivery was similar to that in the early period of preg-nancy.4) The above findings are fully compatible with clinical observations. It is therefore sug-gested that the new apparatus is of use when applied clinically.