A model for the generation of intra-uterine pressure in the human parturient uterus which demonstrates the critical role of the cervix.

A mathematical model is presented which describes the relationship between intrauterine pressure and uterine wall tension. Wall tension is evaluated in terms of muscular contraction in an active myometrium and the modulating effect of a passive, compliant cervix. Using a computer programme which simulates the recruitment of contractile elements in the uterine wall, it is possible to generate theoretical pressure waveforms. The effects on these waveforms produced by changing cervical properties are demonstrated and compared with observed phenomena. The physiological and clinical implications are evaluated.