Sheehan's syndrome, also referred to as postpartum hypopituitarism, is a delayed effect of intrapartum or postpartum hemorrhage — life-threatening blood loss during or after childbirth.

The major organ affected, the pituitary gland, is a small bean-shaped gland at the base of the brain. Hormones from the pituitary regulate the endocrine system, determining when glands increase or decrease production of the hormones that control metabolism, fertility, wound healing and many other body processes. When the supply of pituitary hormones is low, the signs and symptoms may affect almost any part of the body — although they may develop gradually. Hyperpituitarism may seem to cause no symptoms at all. At the other extreme, though, Sheehan's syndrome and other forms of hypopituitarism can cause an adrenal crisis — a sudden, potentially fatal undersupply of the hormone cortisol.

Severe blood loss, that sometimes accompanies childbirth,  deprives body tissues and organs of oxygen, causing tissue death. The result, which may not be apparent for months or even years, is permanent underproduction of pituitary hormones.

In most cases, the signs and symptoms of Sheehan's syndrome appear slowly, after a period of months or even years. But sometimes — such as in a postpartum mother who is breastfeeding — problems may appear right away.

Signs and symptoms of Sheehan's syndrome include: Slowed mental function, weight gain and difficulty staying warm, as a result of an underactive thyroid (hypothyroidism), difficulty breastfeeding, no menstrual periods (amenorrhea) or infrequent menstruation (oligomenorrhea), loss of pubic or underarm hair, low blood pressure, fatigue and or weight loss.

It may be difficult to tell some of the symptoms of Sheehan's syndrome from the usual byproducts of having had a baby. Fatigue, for instance, goes hand in hand with being a new mother. A woman might not realize she has Sheehan's syndrome until she requires treatment for thyroid or adrenal insufficiency.

It's also possible to remain symptom-free with Sheehan's syndrome. Some women unknowingly live for years with pituitary insufficiency, then go into adrenal crisis triggered by extreme physical stressors, such as severe infection or surgery.

Tests such as blood work to determine pituitary hormone levels may be helpful in the diagnosis of Sheehan’s Syndrome.  Also, MRIs or computerized tomography (CT scans)to check the size of the pituitary and to look for other possible causes of pituitary malfunction, such as a pituitary tumor may be helpful.

Treatment for Sheehan's syndrome is lifelong hormone replacement therapy. Medications such as corticosteroids (hydrocortisone or prednisone) replace the adrenal hormones that aren't being produced because of an adrenocorticotropic hormone (ACTH) deficiency.