Possible adrenocortical insufficiency in postmature neonates

Abstract

Total plasma cortisol in cord and neonatal blood was measured by a radioassay method in neonates resulting from (1) term vaginal delivery following uncomplicated labor (control group), (2) term vaginal delivery following fetal distress during labor, (3) postterm, postmature vaginal delivery following fetal distress during labor, and (4) postterm, postmature emergency cesarean section performed because of signs of severe fetal distress during labor. Comparison of the mean peripheral plasma cortisol values showed that whereas the mean level (±S.E.) of the distressd term neonates (22.2 ± 5.3 μg per 100 ml.) use 180 per cent of that of the control group (12.3 ± 1.1 μg per 100 ml.; P < 0.01) the mean level for the vaginally delivered postmature group (7.5 ± 1.8 μg per 100 ml.) was only 61 per cent of that of the control group (P < 0.05). Furthermore, in the postmature group with sufficient intrapartum distress to warrant emergency cesarean section the mean level (4.6 ± 1.5 μg per 100 ml.) was found to be only 37 per cent of that of the control group. No differences were observed among the cord plasma cortisol values. These results are strongly suggestive of a relative adrenocortical insufficiency in postmature neonates. Such insufficiency could result from a defect in any portion of the adrenal-pituitary-hypothalamic axis. Effort is under way to further define such a defect.