An apparatus is disclosed for monitoring fetal cerebral oxygenation during childbirth. The apparatus includes a tunable source of infrared photons, a probe to access a single location on the scalp of the fetus for injecting the infrared photons generated by the photon source, and for receiving scattered photons reflected from within the skull of the fetus. The apparatus at least has first and second detectors for detecting the presence of photons received through the probe at selected different delay intervals so as to be capable of distinguishing photons reflected from different depths or at different instances from within the head of the fetus.