Modification of ovine fetal respiratory-like activity by chronic diazepam administration.

Chronic maternal administration of diazepam resulted in a modification of fetal respiratory-like activity (FRLA) in the sheep. An over-all increase in this activity occurred. This increase was probably due to a rebound effect following periods of acute suppression with each administration of diazepam. Loss of central control in the regulation of FRLA was implied. A complete reversal of a circadian rhythm of FRLA was observed in animals receiving diazepam. These changes have implications with respect to the antenatal monitoring of the fetus and sequelae in the newborn infant.