Causes

Sheehan's syndrome is caused by severe blood loss or extremely low blood pressure during or after childbirth. These factors can be particularly damaging to the pituitary gland, which enlarges during pregnancy, destroying hormone-producing tissue so that the gland can't function normally.

Pituitary hormones regulate the rest of your endocrine system, signaling other glands to increase or decrease production of the hormones that control metabolism, fertility, blood pressure, breast milk production and many other vital processes. A lack of any of these hormones can cause problems throughout the body.

Hormones from the front of your pituitary gland include:

• Growth hormone (GH). This hormone controls bone and tissue growth and maintains the right balance of muscle and fat tissue.
• Thyroid-stimulating hormone (TSH). This hormone stimulates your thyroid gland to produce key hormones that regulate your metabolism. Shortage of TSH results in an underactive thyroid gland (hypothyroidism).
• Luteinizing hormone (LH). In women, LH regulates estrogen.
• Follicle-stimulating hormone (FSH). Working with LH, FSH helps stimulate egg development and ovulation in women.

• Adrenocorticotropic hormone (ACTH). This hormone stimulates your adrenal glands to produce cortisol and other hormones. Cortisol helps your body deal with stress and influences many body functions, including blood pressure, heart function and your immune system.

  A low level of adrenal hormones caused by damage to the pituitary gland is called secondary adrenal insufficiency.

• Prolactin. This hormone regulates the development of female breasts, as well as the production of breast milk.