Distention of the Uterus Activates Its Multiple Pacemakers and Induces Their Coordination

Abstract

In the pregnant human uterus, pacemaker activities and their coordination processes were studied in labor induced by uterine distention. Electrical and mechanical activities of the uterus were simultaneously recorded in 6 midtrimester (normal, n = 4; fetal death, n = 2) and 8 term (normal, n = 7; fetal death, n = 1) patients. Initially, frequent and sporadical spike discharges which did not synchronize with low magnitude and irregular mechanical activities were noted. With time, synchronization of both activities developed. These findings were noted regardless of the gestational stage of the patient and fetal viability. The patterns of development and decreases in mechanical and electrical activities, together with their synchronization patterns, were positively and negatively controlled by uterine distention and its suspension, respectively. These results suggest that the uterus has multiple pacemakers in various locations, and uterine distention works as a trigger for the elevation of excitability and for coordinated and orthodromic activities.

Treatment of abnormal vaginal flora in early pregnancy with clindamycin for the prevention of spontaneous preterm birth: a systematic review and metaanalysis

“…1,2 Mechanisms of disease involved in the “preterm labor syndrome” include infection/inflammation, 3–14 vascular disease, 15–17 uterine overdistension, 18–21 abnormal allograft reaction (eg, rejection), 22–24 an allergic-like phenomenon, 25–28 a progesterone deficiency, 29–32 and cervical disorders. 33–36 The first mechanism of disease responsible for preterm labor and delivery for which a causal link was well-established is infection.…”

Childbirth: The Genetic-Psychosomatic Mother-Child Tango.To the new theory of parturition

“…Even in the non-pregnant uterus, the automatism of uterine SMC has been identified [36], [37], [38]. This manifests as multiple zones of excitation in various parts of the uterus at the onset of labor [39]. Gradually, these zones start following a single rhythm emanating from one center -the pacemaker, usually located in the right corner of the uterus [40].…”