Human fetal respiratory movements: a technique for noninvasive monitoring with the use of a tocodynamometer.

A tocodynamometer applied to the maternal abdomen is used for monitoring human fetal respiratory movements (FRM). This provides a recording of fetal chest wall movements from which observations and measurements relating to fetal respiratory physiology may be made. The FRM must be differentiated from materanal vascular and respiratory movements, as well as fetal movements and cardiac pulsations. The technique lends itself to extended periods of observation, since it does not transmit energy to the fetus as in other techniques. The simplicity of the technique, combined with the use of monitoring devices already available in most hospitals, warrants further observation of this method of respiratory movement monitoring in the developing fetus.