Changes in Serum Cortisol Level During Pregnancy in Ewes and The Effect of Fetal Number

Abstract

This study was carried out to monitor serum cortisol level in pregnant ewes and comparing it with the non-pregnant values. Also, cortisol levels were monitored in single-fetus bearing and twin-fetus bearing ewes. This study was carried out during the breeding season on 31 pregnant and 5 non-pregnant ewes. Pregnancy and fetal numbers were determined through transrectal ultrasonography. Blood samples were collected every two weeks starting at day 30 of pregnancy until day 135 of pregnancy. Blood samples were collected in parallel from non-pregnant ewes as a control group. Cortisol was measured using ELISA.The results showed that serum cortisol levels increased gradually in pregnant ewes until day 90 of pregnancy reaching the highest level at day 135. Serum cortisol level was 4.26 ± 0.16 ng/ml at day 135 of pregnancy, while its level in non-pregnant ewes was 1.85 ± 0.15 ng/ml. Cortisol level was little bit higher in primiparous than pluriparous ewes, however, the difference was not significant. Regarding the effect of fetal number on cortisol level, twin-fetus bearing primiparous ewes had the significantly highest level. In addition, twin-fetus pulriparous ewes had a higher cortisol level than single-fetus bearing ewes. In conclusion, cortisol level increased gradually during pregnancy until day 90 reaching the highest level at day 135 of pregnancy. In addition, cortisol level was significantly higher in twin-fetus bearing ewes than single-fetus bearing ewes. This indicates that twinning increases stress on the pregnant ewes especially in primipara which need more care and attention.

Examination of blood cortisol and some parameters at parturition and on 30th day postpartum in single and twin - pregnant ewes

“…Thus, by stimulating PGF2α release, the level of oxytocin which provides myometrial contractions increases (Nagel et al, 2019). Some studies are reported that there were no significant differences in serum cortisol levels in the prepartum period between single and twin pregnant ewes (Medan et al, 2015) before and after pregnancy (Brunet and Sebastian, 1991) in ewes. Drost et al (1973) found that serum cortisol levels of parturition higher than the levels of prepartum period in ewes.…”

“…Lambs gain approximately 70 % of their birth weight in the last 6 weeks of pregnancy (Siggurdson, 1988). Pregnancy can cause physiological stress that increases maternal plasma cortisol (Keller-Wood, 1996;Medan et al, 2015). Cortisol is a glucocorticoid hormone that produced by the adrenal cortex in response to stress (Medan et al, 2015).…”

“…Pregnancy can cause physiological stress that increases maternal plasma cortisol (Keller-Wood, 1996;Medan et al, 2015). Cortisol is a glucocorticoid hormone that produced by the adrenal cortex in response to stress (Medan et al, 2015). In sheep, lambing causes a sharp release of cortisol from the fetal adrenal glands.…”

A Review of Fetal Development in Pregnancies with Maternal Type 2 Diabetes Mellitus (T2DM)‐ Associated Hypothalamic‐Pituitary‐Adrenal (HPA) Axis Dysregulation: Exploring Links to Pregestational Prediabetes

“…The maternal HPA axis adapts during pregnancy and regulate stress-related deleterious effects on the mother and offspring [70,71]. A non-diabetic pregnancy is a state of hyperactivity of HPA axis and of hypercortisolism especially towards late gestation [72][73][74][75]. The increased cortisol in late gestation is regulated by the placenta, an important source of secreting corticotropin-releasing hormone (CRH), which further enters the maternal pituitary gland via the hypophyseal portal circulation and enhances adrenocorticotropin (ACTH) synthesis and secretion into the peripheral circulation.…”