These are preliminary results of a new method of tracing uterine contractions by impedance recorded with 2 electrodes placed 15 cm from the midline slightly below the umbilicus. A high-frequency electric current of constant intensity was the source of the signal. Results from 2 primiparae in term labor are presented: 1 was spontaneous and uncomplicated; the second had first contractions of low amplitude, then periods of permanent contracture treated with a spasmolytic (Buscopan), and finally a normal delivery. Tracings of typical contractions, confirmed by tocography, resembled a rapidly rising curve (1-3 seconds) associated with beginning of labor pain, a rounded peak, an exponential descent, a brief horizontal pause at the isoelectric line whose duration varied with the length of the contraction, a rapid fall (1-3 seconds), a rounded nadir, and finally an exponential return to the isoelectric line. The return to base line was preceded 10-15 seconds by a slight dip. This type of tracing was associated with normal contractions and was not influenced by fetal movements. The method delineated contractions, relaxations, and the effect of medication instantly.