Assessing mid‐trimester salivary cortisol levels across three consecutive days in pregnant women using an at‐home collection protocol

Abstract

The Pregnancy Outcomes and Community Health (POUCH) Study enrolled women in their 15th to 27th week of pregnancy from 52 prenatal clinics located in five communities. After the study began, an at-home protocol to measure maternal stress was added, which included collection of urine and saliva twice a day (waking = AM, bedtime = PM) for three consecutive days, and completion of a daily diary. The at-home protocol was in place for 2852 POUCH participants at enrollment, and 81.3% (n = 2318) consented and returned samples and diary. For these analyses, salivary cortisol was analysed in a subset of 846 women who delivered at term. Day-to-day correlation coefficients for AM cortisol (0.45-0.55) exceeded those for PM cortisol (0.31-0.43). Study diaries indicated that there was variation in the time interval between waking and sample collection. Analyses of discrete intervals showed the same awakening response pattern in cortisol levels that has been reported in studies with serial AM sampling. The adjusted mean AM cortisol (microg/dL) was 0.506 at 0-15 min post-waking, 0.544 at 16-30 min (P < 0.05), 0.582 at 31-60 min (P < 0.01), and 0.515 at >60 min post-waking. In addition, adjusted mean AM cortisol in samples collected at or before 9 a.m. was higher than that in samples collected after 9 a.m. (0.564 vs. 0.510 microg/dL, P < 0.01). Among working women, adjusted mean AM cortisol was higher on work days than non-work days (0.564 vs. 0.489 microg/dL, P < 0.01), and in multiparae compared with primiparae (0.551 vs. 0.502 microg/dL, P = 0.07). The parity effect was not evident in non-working women. The adjusted mean PM cortisol significantly increased as week of pregnancy at sampling increased, but was not significantly related to time of collection, work day and parity. Factors influencing AM and PM cortisol levels in pregnancy appear to differ. In studies of AM cortisol levels, it is important to gather data on time of sample collection, interval from waking to sample collection, parity and work.

Dysregulation of Diurnal Salivary Cortisol Production Is Associated with Spontaneous Preterm Delivery: A Pilot Study

“…Conversely, women who delivered at term presented a physiological fluctuation of diurnal salivary cortisol with higher concentrations in the morning. This latter evidence represents a sensitive marker of normal HPA axis activity [20,21,22,23], supporting previous reports of normal circadian cortisol fluctuations throughout normal gestation [24,25]. …”

Antenatal Depression in a Multi-Ethnic, Community Sample of Canadian Immigrants: Psychosocial Correlates and Hypothalamic-Pituitary-Adrenal Axis Function

“…While attempts were made to control for ethnicity, by including region of origin as a covariate, the small sample size may have masked differences in prenatal cortisol activity by ethnicity as noted previously. [15][16][17] Additionally, cortisol analyses did not control for potential differences between weekdays and weekends, and compliance with the saliva sampling protocol was not objectively measured. Finally, prenatal depression was not clinically diagnosed but rather relied on maternal self-report.…”

“…Our assessment of HPA axis activity was thorough, measuring the CAR and evening cortisol levels over 2 days as previously recommended 52,53 and including diaries. 15 Both the CAR and evening cortisol levels were measured as they represent distinct functions of the HPA axis, 54 are present and measurable during pregnancy, 33,[55][56][57][58] and have been associated with obstetric outcomes. 39,59,60 Results are additionally strengthened by their persistence after controlling for known covariates (for example, parity).…”

“…Pearson correlations explored possible covariates (that is, variables known to affect the cortisol variables of interest), namely, time of awakening, 36 number of hours slept, 37 weeks of gestation, 38 parity, 39 and region of origin. [15][16][17] A MANOVA was performed to examine differences between women with high and low depressive symptoms on any of the cortisol variables of interest. Partial correlations were used to run exploratory analyses examining possible associations between SLEs and the cortisol variables of interest.…”

The diagnosis of Cushing’s syndrome

“…Additionally, activation of the HPA axis occurs in several disorders other than Cushing's syndrome and may confound late-night salivary cortisol measurement. Pregnancy, alcoholism, and psychiatric disorders are all associated with elevated late-night cortisol levels [27][28][29][30]. [31].…”