Prior studies have provided evidence for reduced fetal adrenal production of dehydroepiandrosterone sulfate and normal or increased production of cortisol in association with pregnancy complications believed to result in fetal stress. In the present study, we sought to determine the status of adrenal steroidogenesis in 36 term infants having respiratory acidosis and to compare acidotic infants to (i) non-acidotic infants matched for pregnancy complications, gestational age, and method and indications for delivery (control infants), and (ii) non-acidotic infants of non-complicated pregnancies who were also matched for gestational age and delivery method (normal infants). Umbilical cord serum levels of dehydroepiandrosterone sulfate were lowest in acidotic infants, intermediate in the condition matched control infants and highest in the non-acidotic infants of normal pregnancies. On the other hand, cortisol levels were highest in acidotic infants, intermediate in control infants and lowest in the normal infants. These data suggest that various pregnancy complications give rise to significant alterations in adrenal steroidogenesis (decreased dehydroepiandrosterone sulfate and increased cortisol). Intrauterine deterioration during labor with resultant respiratory acidosis has an additional effect on fetal adrenal function.