Maternal hair cortisol concentrations across pregnancy and the early postpartum period in a Puerto Rican sample

Abstract

Objective: Hair cortisol is a noninvasive, long-term biomarker of human stress. Strengths and weaknesses of this biomarker as a proxy measure of perinatal stress are not yet well understood. Hair cortisol data were collected from pregnant women in Puerto Rico to investigate maternal cortisol level variance across pregnancy. Methods: In 2017, we recruited 86 pregnant women planning to birth at a large urban hospital. We aimed to collect four hair samples from each participant, one in each trimester and one in the postpartum period.Results: Median cortisol in the first trimester (n = 82) was 5.7 picograms/ milligram (pg/mg) (range: 1.0-62.4). In the second, third, and postpartum periods, the medians were 6.8 pg/mg (1.0-69.5), (n = 46), 20.1 pg/mg (5.6-89.0), (n = 30), and 14.1 pg/mg (1.7-39.8), (n = 9), respectively. These medians disguise a 10-fold and 50-fold variability for two participants. Our sample sizes declined sharply when Hurricane Maria caused major disruptions in services and participants' lives. Conclusion:Maternal hair cortisol concentrations were lower in the first and second trimester than the third trimester and early postpartum period. We also observed a wide range of variation in cortisol levels throughout pregnancy and in the postpartum period.

Applying minimally invasive biomarkers of chronic stress across complex ecological contexts

“…Moreover, serially collected hair/fingernail samples may yield novel insights into associations between chronic stress and health across development. For instance, by following changes in cortisol output throughout pregnancy, repeated maternal hair collection during each trimester and postpartum may help reveal mechanisms linking maternal chronic stress and perinatal/infant health outcomes (Horan et al, 2022 ).…”

“…Following extraction and evaporation, the dry extracts are reconstituted in assay buffer, and resultant samples are assayed using commercially available ELISA kits. Formulas accounting for the quantity of buffer used to reconstitute the sample, the proportion of the original extraction dried down, and the initial weight of powdered hair are then used to calculate HCC expressed as pg/mg (Helfrecht et al, 2018 ; Horan et al, 2022 ).…”

Minimally invasive biomarkers in human population biology research, part 2: An introduction to the special issue

“…This systematic approach to development and optimization of biomarkers for use with minimally invasively collected samples includes extensive testing and attention to key assay performance parameters and to issues such as analyte stability. Following methods development, additional work is needed to establish reference ranges, such as was the focus of work by Horan et al (2022) on hair cortisol during pregnancy. These assay protocols must be made freely available and widely disseminated to enable high-quality data collection and allow comparisons between studies.…”

“…For human biologists interested in chronic stress and health, this paper is a must read. Horan et al (2022) investigate maternal cortisol variation across pregnancy in a Puerto Rican sample using cortisol extracted from hair, a relatively new noninvasive and long-term measure of chronic stress. While hair is easy to collect (though it should be noted that it is not acceptable to collect in all cultural contexts), extract and store-and it is not subject to the diurnal fluctuations that complicate research with saliva samples-there are challenges because hair cortisol is relatively new and all the methodological issues and reference ranges have not yet been established.…”

“…The methods development and innovative biomarker applications described in this special issue provide new tools for the field to expand data collection to allow new perspectives, including on skeletal dynamics and osteoporosis (Devlin et al, 2022), patterns of cancers (DeLouize, Eick, et al, 2022), and stress experienced during pregnancy (Horan et al, 2022). The growing use of POCT also helps expand these perspectives specifically with regard to health biomarkers (Gildner et al, 2022).…”