Measure of contraction strength in labor: area and amplitude.

A retrospective, off-line study of the relationship of the area under the intrauterine pressure waveform (Area) to amplitude was performed on contractions from patients in normal labor and hypocontractile labor before and during oxytocin therapy. A linear correlation of Area and amplitude can be identified in the study of large numbers of contractions. Unfortunately, the wide scatter of the values of either measure for a narrow range of values of the other precludes the use of Area as a clinically useful aid in assessing hypocontractility or oxytocin response from small numbers of contractions.