Hair Testing May Offer Insights into Asthma-Related Complications in Pregnancy

In addition to being time consuming, these measurements are difficult to interpret as they reflect only one point in time. Cortisol fluctuates during the day. Hair, on the other hand, stores cortisol levels over a long period of time. Each segment of about 1 cm offers a look back at what the levels were during a particular month.

To investigate whether hair samples could be used to assess effects of the chronic inflammatory lung disease asthma on cortisol levels during pregnancy, a research team led by Gideon Koren, MD, University of Toronto (Canada), and Bruce Carleton, PharmD, University of British Columbia (Canada), tested for cortisol in hair samples from 93 pregnant women, of whom 62 had asthma and 31 did not. About half the women with asthma were being treated with inhaled corticosteroids.

“For both the control and the asthma groups we could see a rise in cortisol over the course of the pregnancy and then a decline during the postpartum period,” said study coauthor Laura Smy, PhD student, University of Toronto (Canada). This finding supports the use of hair samples as a tool for assessing cortisol levels during pregnancy.

The study also made an unanticipated finding, however. “For the individuals with asthma, whether or not they were using inhaled corticosteroids, their response to the cortisol increase was dampened,” said Smy, “They had significantly lower hair cortisol levels during both their 2nd and 3rd trimesters than the women in the control group.” The finding suggests that levels of cortisol tend to be lower among pregnant women with asthma. This may be due to “adrenal fatigue”—prolonged exposure to high cortisol levels that eventually causes the adrenal glands to significantly reduce their output of the hormone.

While research has established that high cortisol levels are associated with an elevated risk of miscarriage and premature birth, some increase during pregnancy may have a beneficial effect. Indeed, research suggests that higher cortisol levels late in pregnancy are needed for fetal organs to mature, especially the lungs, thyroid, and digestive tract. The new study offers a simpler tool that could help scientists unravel this complicated relationship and determine if and how cortisol is linked to pregnancy outcomes.

“We hope hair samples will help establish the role that changes in cortisol levels throughout pregnancy have on the health of women and their children,” said Smy. Future research will be needed to both confirm this study’s findings and to determine the role that changes in cortisol during pregnancy may have on pregnancy outcomes and fetal wellbeing.

Related Links:
American Association for Clinical Chemistry (AACC)
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