Signs and symptoms of Sheehan's syndrome typically appear slowly, after a period of months or even years. But sometimes problems appear right away, such as the inability to breast-feed.

Signs and symptoms of Sheehan's syndrome occur because of having too little of the hormones the pituitary gland controls: thyroid, adrenal, breast milk production and menstrual function hormones. These include:

• Difficulty breast-feeding or an inability to breast-feed
• No menstrual periods (amenorrhea) or infrequent menstruation (oligomenorrhea)
• Inability to regrow shaved pubic hair
• Slowed mental function, weight gain and difficulty staying warm as a result of an underactive thyroid (hypothyroidism)
• Low blood pressure (hypotension)
• Low blood sugar (hypoglycemia)
• Fatigue
• Irregular heartbeat
• Breast shrinkage

For many women, Sheehan's syndrome symptoms are nonspecific and often thought to be caused by other things. Fatigue, for instance, goes hand in hand with being a new mother. You might not realize you have Sheehan's syndrome until you need treatment for thyroid or adrenal insufficiency.

It's also possible to remain relatively symptom-free with Sheehan's syndrome, depending on the extent of damage to the pituitary gland. Some women live for years not knowing their pituitary isn't working properly. Then an extreme physical stressor, such as severe infection or surgery, triggers an adrenal crisis.

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 your body.

Hormones from the front of your pituitary 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 pituitary damage is called secondary adrenal insufficiency.

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

Any condition that increases the chance of severe blood loss (hemorrhage) or low blood pressure during childbirth, such as being pregnant with multiples or having a problem with the placenta, can increase your risk of Sheehan's syndrome.

Hemorrhage is a rare childbirth complication, however, and Sheehan's syndrome is even more uncommon. Both risks are greatly reduced with proper care and monitoring during labor and delivery.

Because pituitary hormones control so many aspects of your metabolism, Sheehan's syndrome can cause a number of problems, including:

• Adrenal crisis, a serious condition in which your adrenal glands produce too little of the hormone cortisol
• Low blood pressure
• Unintended weight loss
• Menstrual irregularities

Adrenal crisis: Life-threatening situation

The most serious complication is adrenal crisis, a sudden, life-threatening state that can lead to extremely low blood pressure, shock, coma and death.

Adrenal crisis usually occurs when your body is under marked stress — such as during surgery or a serious illness — and your adrenal glands produce too little cortisol, a powerful stress hormone.

Because of the potentially serious consequences of adrenal insufficiency, your doctor is likely to recommend that you wear a medical alert bracelet.