Cortisol during human fetal life: characterization of a method for processing small quantities of newborn hair from 26 to 42 weeks gestation

OBJECTIVE: Fetal cortisol may be reflected in hair collected shortly after birth. The objective of this study was to determine the range of human fetal hair cortisol concentrations (HCC) in live-born neonates using an approach for processing small quantities of hair. MATERIALS AND METHODS: Hair was cut on the day of birth from neonates and their mothers, born between 26 and 42 weeks gestational age (GA). HCC was determined by enzyme immunoassay. Maternal sociodemographics and birth data were collected. T-tests, ANOVA, Pearson correlation, and Wilcoxon Signed Rank test were used as appropriate. RESULTS: Ninety maternal and neonatal hair samples were cut from 79 term (T) and 11 preterm (PT) delivered pregnancies. All samples weighed >= 2.5 mg. Fetal HCC correlated with GA (r = .25, p = .02) and birth weight (r = .25, p = .03) and was lower in PT (4.3 +/-.3 LN pg/mg) than T (5.3 +/- .1, LN pg/mg, p <.001) neonates. No significant relationships were seen between fetal HCC and maternal characteristics or maternal HCC. Fetal HCC was significantly higher than maternal HCC. CONCLUSION: Fetal cortisol exposure was determined using this approach for processing small amounts of hair. Preterm neonates have significantly lower HCC than term neonates and fetal HCC is associated with GA at delivery and birth weight. Fetal HCC is significantly higher than maternal HCC cut on the same day. These data provide novel information on the intrauterine fetal cortisol environment.