ACTH-dependent Cushing's syndrome is a heterogeneous disorder requiring a multidisciplinary and individualized approach to patient management. Generally, the treatment of choice for ACTH-dependent Cushing's syndrome is curative surgery with selective pituitary or ectopic corticotroph tumor resection. Second-line treatments include more radical surgery, radiation therapy (for Cushing's disease), medical therapy, and bilateral adrenalectomy. Because of the significant morbidity of Cushing's syndrome, early diagnosis and prompt therapy are warranted.

Pregnancy dramatically affects the hypothalamic-pituitary-adrenal axis leading to increased circulating cortisol and ACTH levels during gestation, reaching values in the range seen in Cushing's syndrome (CS). The cause(s) of increased ACTH may include placental synthesis and release of biologically active CRH and ACTH, pituitary desensitization to cortisol feedback, or enhanced pituitary responses to corticotropin-releasing factors. In this context, challenges in diagnosis and management of disorders of the hypothalamic-pituitary-adrenal axis in pregnancy are discussed. CS in pregnancy is uncommon and is associated with fetal morbidity and mortality. The diagnosis may be missed because of overlapping clinical and biochemical features in pregnancy. The proportion of patients with primary adrenal causes of CS is increased in pregnancy. CRH stimulation testing and inferior petrosal sinus sampling can identify patients with Cushing's disease. Surgery is a safe option for treatment in the second trimester; otherwise medical therapy may be used. Women with known adrenal insufficiency that is appropriately treated can expect to have uneventful pregnancies. Whereas a fetal/placental source of cortisol may mitigate crisis during gestation, unrecognized adrenal insufficiency may lead to maternal or fetal demise either during gestation or in the puerperium. Appropriate treatment and management of labor are reviewed.

Cushing's syndrome (CS) occurs rarely during pregnancy. We investigated and treated four patients with pituitary-dependent Cushing's syndrome during pregnancy over a 15-yr period at the National Institutes of Health. Except for preservation of menses before conception, our patients presented with typical clinical features, increased urinary free cortisol, and loss of diurnal variation of cortisol. The diagnosis was facilitated, without complications, by the use of CRH testing and inferior petrosal sinus sampling in three women. Transsphenoidal pituitary surgery achieved remission in three women, but there were two fetal/neonatal deaths. This experience and review of 136 previous reports suggest that: 1) urinary free cortisol in CS patients overlaps the normal pregnant range; 2) ACTH levels are not suppressed in adrenal causes of CS, which may be identified by the 8-mg dexamethasone test; 3) inferior petrosal sinus sampling and transsphenoidal pituitary surgery, the optimal diagnostic test and treatment for nonpregnant patients with pituitary-dependent Cushing's syndrome, can safely facilitate the management of pregnant patients; and 4) surgery may achieve remission during pregnancy, but the prognosis for the fetus remains guarded. It is likely that earlier recognition and treatment would improve outcome. There is a need for development of criteria for interpretation of diagnostic tests and increased consideration of CS in pregnancy.

CS is associated with impaired HRQL, which partially resolves after treatment. At longer-term follow-up, however, there is residual impairment of HRQL. Determination of modifiable factors that contribute to impaired HRQL may help reduce the physical and psychosocial burden of this disease.