Management of fetal endocrine disorders.

A number of maternal endocrine disorders, when active during pregnancy, can have adverse effects on the newborn. Frequently, these affects can be anticipated as in Graves' disease, or the adverse effect can be prevented as in macrosomia in the infant of the diabetic mother. Occasionally, there are opportunities for prenatal treatment of a fetal endocrine disorder. For instance, a large goitre that may cause problems during delivery can be treated with thyroid hormones administered intra-amniotically or as analogues that cross the placenta. A uniquely effective form of treatment for prevention of a major birth defect is administration of dexamethasone to the mother to avoid virilisation of a female fetus with congenital adrenal hyperplasia (CAH). However, such treatment should only be conducted within the framework of a clinical trial as the long-term effects of exposure to potent glucocorticoids in utero are unknown. Intrauterine growth retardation, which affects about 5% of newborns, is currently not amenable to direct pharmacological treatment before birth. However, there are more practical options for managing this condition, including improved maternal nutrition and avoidance of toxins injurious to fetal growth.