title: THe relationship between myometrial activity and sleep state and breathing in fetal sheep throughout the last third of gestation.
abstract: Between 106 and 144 days' gestation, periods of uterine electromyographic (EMG) activity and associated increases in uterine tone (contractures) were accompanied by a change in fetal ocular activity in 294 (63%) of 467 cases. In 260 (88.4%) of the changes, there was a switch fromm the active to nonactive state. The incidence of this change was significantly greater (p < 0.01) than the switch from the nonactive to the active state. The fetal electrocorticogram changed state in 34 (74%) of 46 contractures, the change being from low-amplitude to high-amplitude activity in 28 (82%) of the cases. This difference was significant (p < 0.01). Fetal breathing movements (FBM), as indicated by activity of the posterior cricoarytenoid muscle, changed in 134 (55%) of 243 contractures, the change being from active to the quiescent state in 115 (85%) of contractures. Diaphragmatic activity changed in 11 (61%) of 183 contractures, with a change from activity to quiescence occurring in 100 instances (90%). Changes in tracheal pressure were associated with an altered state of FBM in 190 (61%) of 314 contractures, and the change was from the presence of FBM to absence of them in 178 (94%) of the changes. In all three of these indicators of FBM, the change from breathing activity to quiescence was statistically significant (p < 0.01).
mesh_terms: D000818:Animals; D003964:Diaphragm / Q000502:physiology; D004576:Electromyography; D004585:Electrooculography; D005260:Female; D005333:Fetus / Q000502:physiology*; D007821:Laryngeal Muscles / Q000502:physiology; D011247:Pregnancy; D012119:Respiration; D012756:Sheep / Q000502:physiology*; D012894:Sleep Stages / Q000502:physiology*; D014132:Trachea / Q000502:physiology; D014590:Uterine Contraction