In this preliminary study, maternal and fetal blood lactate and 3-hydroxybutyrate (3-OHB) levels were assayed by specific enzymatic spectrophotometric methods in two groups of parturient Nigerian women during the three labour stages and their newborn: (i) thirty two women with babies' Apgar score > or = 6, and, (ii) eighteen women with babies' Apgar scores á 5. Cord blood was collected within 1 min. of cord clamping. In all the patients there was a lactate gradient between the foetus and mother. Neonates with Apgar score < 5 had greater cord blood 3-OHB levels. This could indicate reduced utilisation and/or increased production of this metabolite. Since in states of glucose deprivation as could be found in placenta insufficiency, 3-OHB is utilised by the foetus for the synthesis of essential cerebral lipids. It is speculated that the immediate poor clinical condition of babies with low Apgar scores may be a consequence of reduced synthesis of these cerebral lipids as they were unable to utilise circulating 3-OHB. The rapid response to routine resuscitative measures in these newborn babies could also indicate improved 3-OHB utilisation secondary to an improved tissue oxygenation status. These hypotheses from the basis for further studies.