Prenatal maternal stress has been frequently linked with elevated levels of maternal endogenous cortisol. Maternal stress is commonly considered as an important risk factor for spontaneous abortion. Furthermore, hormones involved in stress exert an effect on the hypothalamic pituitary gonadal axis which is stress reaction increased secretion of cortisol and prolactin. High concentrations of cortisol result in insensitivity of the pituitary gland to gonadotropin releasing hormone and of the ovaries to luteinizing hormone (LH). The consequence is the limitation in the release of LH, Follicle Stimulating Hormone (FSH), and estrogens when a prolongation of the follicular phase occurs, the menstrual cycle will become irregular and prolonged, and the probability of ovulation decreases .
The majority of miscarriages occur within the first 3 weeks after conception (or roughly 5 weeks after the last menstrual period). This research studied the association between miscarriage and levels of maternal urinary cortisol during the first 3 weeks after conception. According to this study, pregnancies characterized by increased maternal cortisol during this period (within participant analyses) were more likely to result in spontaneous abortion. In conclusion, the study explains the link between increased levels in this stress marker with a higher risk of early pregnancy loss in human.
Of the 22 observed pregnancies, 9 were carried to term (‘‘successful’’) and 13 were lost (‘‘unsuccessful’’). Mean standardized cortisol levels were higher in unsuccessful than in successful pregnancies. The study calculated the comparative risk of spontaneous abortion according to cortisol exposure. Pregnancies in which the average standardized cortisol during the first 3 weeks after conception, or between ovulation and pregnancy loss was equal to or less than the woman’s overall cortisol baseline (OCB) were classified as exposed to ‘‘normal cortisol’’ (n =10). When the 3 weeks post conception average cortisol level was above the woman’s OCB (n = 12), the pregnancy was classified as exposed to ‘‘increased cortisol.’’ Pregnancies ex-posed to increased cortisol were 2.7 times (95% confidence interval = 1.2-6.2) more likely to be unsuccessful (lost) than those exposed to normal cortisol levels. Whereas 90% of the increased cortisol pregnancies resulted in spontaneous abortions, only 33% of the normal cortisol pregnancies were lost .
Table 1 Cortisol exposure and pregnancy outcome .
This research shows an association between increased maternal cortisol and higher risk of miscarriage within the first 3 weeks of conception, together with the failure of previous research to find such an association later during gestation, suggests that pregnancy may be particularly sensitive to maternal stress during the placentation period.
1. Wdowiak, Artur, et al. “Interactions of Cortisol and Prolactin with Other Selected Menstrual Cycle Hormones Affecting the Chances of Conception in Infertile Women.” International Journal of Environmental Research and Public Health 17.20 (2020): 7537.
2. Nepomnaschy, Pablo A., et al. “Cortisol levels and very early pregnancy loss in humans.” Proceedings of the National Academy of Sciences 103.10 (2006): 3938-3942.