EFFECTS OF INTRAPARTUM STRESS ON FETAL ADRENAL-FUNCTION

OBJECTIVE: Our purpose was to characterize the fetal adrenal response to acute intrapartum stress in otherwise uncomplicated pregnancies. ST UDY DESIGN: Term infants (n = 61) diagnosed as having fetal distress d uring labor, as indicated by heart rate abnormalities, and delivered o f women having normal pregnancies were pair-matched with 61 infants sh owing no signs of fetal distress or acidemia (controls) on the basis o f gestational age and delivery method. Umbilical cord serum dehydroepi androsterone sulfate and cortisol were measured, and the data were ana lyzed by two-tailed t test, Fisher's exact test, analysis of variance, and Tukey's multiple range test. RESULTS: Distressed infants had lowe r serum levels of dehydroepiandrosterone sulfate (3992 +/- 246 nmol/L, mean +/- SE) than control infants (4853 +/- 283 nmol/L); distressed i nfants also had higher levels of cortisol (412 +/- 17 nmol/L) than did control infants (299 +/- 16 nmol/L). The dehydroepiandrosterone sulfa te/cortisol ratios in control infants (i 7.7 +/- 1.2) were almost twic e those of distressed infants (10.8 +/- 0.9). These same relationships also were noted when the infant pairs were segregated according to wh ether delivered vaginally (21 pairs) or by cesarean section (40 pairs) . The abnormalities in steroid levels in the distressed infants were i ndependent of the presence or absence of acidemia. CONCLUSION: Intrapa rtum stress acutely alters fetal adrenal steroidogenesis, leading to i ncreased production of cortisol and decreased secretion of dehydroepia ndrosterone sulfate.