Corticosteroids and pregnancy.

Pregnancy results in major changes in the hypothalamo-pituitary-adrenal (HPA) axis, which in turn influence fetal growth and the timing of labor. From the beginning of the second trimester maternal cortisol secretion increases, and in late pregnancy the placenta, in large part mediated through corticotroph-releasing hormone, plays a crucial role in the regulation of the fetal HPA axis to ensure the synchronization of the various processes involved in parturition. Exposure of the fetus to excess glucocorticoid results in intrauterine growth failure and possibly "programs" the development of cardiovascular disease in adult life. Biochemical assessment of the HPA axis is complicated by the estrogen-induced elevation of circulating cortisol-binding globulin, resulting in misleadingly high circulating cortisol levels The hypercortisolemia of Cushing's syndrome causes infertility, but if pregnancy does occur it can result in increased morbidity and mortality in mother and fetus. However, the prospects of a successful pregnancy are greatly improved with control of hypercortisolemia by surgery and medical therapy with metyrapone. Hypoadrenalism can be difficult to diagnose during pregnancy but, once the diagnosis is made, with careful monitoring, dose adjustment as indicated, and parenteral cover for labor, a successful pregnancy should result.