Ontogeny of fasting small intestinal motor activity in the human infant.

A clearly defined progression of fasting small intestinal motor development is seen in the human infant from disorganised low amplitude motor activity before 31 weeks gestation through an intermediate phase of increasing motor organisation and amplitude to the development of a normal cyclical pattern of motor activity with clearly defined phase I, II, and III activity between 37 weeks gestation and term. With increasing maturity smooth muscle contractility [gastric antral pressure (5-30 mmHg), average duodenal pressure (2-12 mmHg)], propagation and slow wave frequency (10.5-12.5 cpm) all increased in a significant fashion (p less than 0.01). The stage of development of fasting motor activity in the small intestine of the preterm infant can now be readily predicted from the gestational age of the infant.