Uterine activity in the multiparous patient

There were 149 parous patients with normal cervical dilatation patterns studied. The purpose was to quantitate and characterize uterine activity in a group of multiparous patients with normal labor using our present on-line method and to evaluate our method against pervious work done on uterine activity. A mean total of 5,299 uterine activity units (UAU) was required to progress from 4 cm. through delivery. In the patients receiving oxytocin 5,907 UAU were required and 4,498 UAU for those not receiving oxytocin. Of the total uterine work from 4 cm. to delivery, 49.4% was required to progress from 4 to 6 cm. 38.7% to progress from 6 to 10 cm., and 11.9% for the second stage. This study establishes in a quantitative way, using on-line methods, the patterns of uterine activity expended by the parous patient in normal labor and can be compared to previous off-line and manual evaluations. These data can be compared with the on-line observations previously made in a primiparous group, and will be fundamental to automated evaluations including definitions of abnormal labor.