Stress caused by environmental effects on the birth process and some of the labor hormones at rats: ideal birth environment and hormones

Abstract

Objective The aim of this study was to compare the effect of environmental conditions on the birth hormones and the labor of rats. Materials and methods This Study is animal experiment. A total of of 18 pregnant Sprague Dawley rats were divided into control, stress and enriched groups. Animals in the stress group were exposed to unexpected variable stress paradigm three times a day during the third trimester of their pregnancies. Whereas animals raised in the enriched environment were kept in larger cages equipped with various toys. They were subjected to open field test for 5 minutes in the last trimester. Blood samples were taken from the tail vein at the beginning of birth, and 10 parameters (including corticotropin-releasing hormone, oxytocin, endorphin, epinephrine, norepinephrine, prolactin, estrogen, progesterone, vasopressin, and brain-derived neurotrophic factor) involved in labor were assessed. Kruskal Wallis, Mann Whitney U, and Spearman’s rho correlation analysis were used to compare data. Results Interactions of hormones were significantly different among the groups. While hormonal interactions in the control group were similar to the physiological parameters, other groups displayed various results. There were significant (p < .05) differences in the values of corticotropin-releasing hormone (CRH) and vasopressin hormone levels. In the open Field test, standing distribution scores of animals displayed differences among control, stress and enriched environment groups (p < .05). Conclusion These results showed that labor environment diversely affects physiology aspects of birth. It is known that many factors such as procedures in a hospital environment, birth environment, noise, and birth position affect the hormones at birth. Therefore, the birth environment, either at home or at the hospital, needs to be well-organized accordingly.