Usefulness of a new tactile sensor for measurement of uterine cervical ripening in mice in a quantitative and noninvasive manner

OBJECTIVE: The purpose of this study was to establish a method with a new tactile sensor for determining in a quantitative and noninvasive manner the extent of uterine cervical ripening. STUDY DESIGN: We used a newly designed tactile sensor to measure the softness of the cervix in untreated nonpregnant, pregnant, parturient, and nursing mice and then on day 15 of gestation in pregnant mice treated with dehydroepiandrosterone sulfate or Escherichia coli lipopolysaccharide. Additionally, to elucidate the correlation between the extent of cervical softness and its morphologic changes, we observed microscopically the uterine cervices. RESULTS: The hardness of the murine cervix decreased with the progression of pregnancy and became minimal at delivery. We demonstrated for the first time with a tactile sensor for measuring hardness that dehydroepiandrosterone sulfate and lipopolysaccharide significantly decreased the stiffness of the murine cervix. These findings were supported by the morphologic observations on the cervices. CONCLUSIONS: These results show that the tactile sensor for measuring hardness makes it possible to determine the extent of cervical ripening quantitatively rather than qualitatively. We consider that cervical ripening determined objectively in this manner is a good parameter to predict the onset of preterm delivery. (Am J Obstet Gynecol 1996;175:713-8.)