Investigating the effect of hormonal contraceptive use on salivary cortisol response to a CO2 challenge

Abstract

Hormonal contraceptive (HC) use has been associated with many physiological effects, such as blunted cortisol stress responses, when compared to naturally cycling (NC) women. However, no previous studies comparing these groups have utilized a CO2 challenge to induce stress. Therefore, the aim of the current study was to use a CO2 challenge to compare cortisol stress reactivity in women using HC relative to NC women. While this task has been previously used to induce panic, few studies have assessed its effects on cortisol, especially as it relates to HC use. Thirty-five women (19 current HC users,16 self-reported NC women) were assessed in the lab. Participants had a mean age of 25.2 years and were 74.3% White. A 35% CO2 challenge was used to provoke a stress response. Saliva samples were collected to measure cortisol (1 pre-stress baseline sample, 5 post-stress samples). Linear mixed effects modeling was used to examine whether there was a significant increase in cortisol following the challenge. There were no group differences in baseline cortisol (b = -.0117, p =.801), however, there was a significant difference in cortisol responses from baseline, with NC women having a more robust cortisol response (linear effect, b=.0065, p=.001; quadratic effect, b=-.0001, p<.001). Results are consistent with previous research demonstrating a more blunted cortisol response to a laboratory-based stressor among individuals using HC. In contrast, participants in the NC group displayed greater post-stress peak cortisol levels and a clear down-regulatory response.