Glucocorticoid Maturation of Fetal Cardiovascular Function

• Published in: Trends in molecular medicine 2020-02, Vol.26 (2), p.170-184
• Main Authors: Jellyman, Juanita K., Fletcher, Andrew J.W., Fowden, Abigail L., Giussani, Dino A.
• Format: Article
• Language: English
• Subjects: Animals; betamethasone; Cardiovascular System - drug effects; cortisol; dexamethasone; fetus; Fetus - drug effects; Glucocorticoids - pharmacology; Glucocorticoids - therapeutic use; Humans; hypoxia; Premature Birth - physiopathology; preterm
• ISSN: 1471-4914; 1471-499X
• DOI: 10.1016/j.molmed.2019.09.005

The last decade has seen rapid advances in the understanding of the central role of glucocorticoids in preparing the fetus for life after birth. However, relative to other organ systems, maturation by glucocorticoids of the fetal cardiovascular system has been ignored. Here, we review the effects of glucocorticoids on fetal basal cardiovascular function and on the fetal cardiovascular defense responses to acute stress. This is important because glucocorticoid-driven maturational changes in fetal cardiovascular function under basal and stressful conditions are central to the successful transition from intra- to extrauterine life. The cost–benefit balance for the cardiovascular health of the preterm baby of antenatal glucocorticoid therapy administered to pregnant women threatened with preterm birth is also discussed. Glucocorticoids mature basal cardiovascular function in the fetus during late gestation, increasing peripheral resistance and arterial blood pressure. Glucocorticoids affect the central regulation of fetal blood pressure, elevating the baroreflex set point, which maintains the greater resting blood pressure.Glucocorticoids also mature the fetal cardiovascular defense against hypoxic stress. Fetal bradycardia switches from being transient to sustained, and the increase in femoral resistance during hypoxia is enhanced. Bradycardia helps to limit myocardial oxygen consumption and the increased peripheral resistance helps to prioritize oxygen delivery to the fetal brain.Exposure to glucocorticoids of the preterm fetus through maternal clinical therapy therefore accelerates cardiovascular maturation, improving basal cardiovascular function and enhancing the fetal cardiovascular defense against physiological stress.