The dynamics of human fetal breathing movements; a multiscan echofetographic approach

Fetal breathing movements are characterized by retractions of the thoracic cage, an increase in the thoracic kyphosis and an expansion of the abdominal wall during each such thoracic movement. These findings can be explained by assuming that the movements of the thoracic cage and abdominal wall are initiated by contractions of the diaphragm itself, as well as the intrathoracic and intraabdominal pressure changes belonging to them. When an echographic technique is used, a positive identification of the start of each inspiratory phase will only be possible if these breathing movements can be clearly differentiated.