Sheehan’s Syndrome is a rare but serious condition that exclusively affects women after childbirth. This disorder involves damage to the pituitary gland, often called the “master gland,” located at the base of the brain. The damage results from severe blood loss during or immediately following delivery, leading to a deficiency in the hormones the pituitary gland produces. If left untreated, these hormonal deficiencies can affect many body functions and lead to life-threatening complications.
Defining the Syndrome and Its Origin
Sheehan’s Syndrome, also known as postpartum pituitary gland necrosis, is caused by a lack of oxygen reaching the pituitary gland. During pregnancy, the anterior pituitary gland significantly enlarges due to the proliferation of prolactin-producing cells, making it highly vulnerable to changes in blood supply. The primary trigger is severe postpartum hemorrhage, which causes a drastic drop in blood pressure (hypotension). This results in ischemic necrosis, where blood vessels constrict, starving the enlarged tissue of oxygen and causing cell death. The posterior pituitary gland is typically spared because it receives its blood supply from a different, higher-pressure system.
The extent of the blood loss and resulting tissue death determines the severity of the condition. Damage can range from partial to complete failure of the anterior pituitary gland, known as panhypopituitarism.
Recognizing the Signs of Hormone Deficiency
The symptoms of Sheehan’s Syndrome arise from the loss of anterior pituitary hormones, which control many other glands. The presentation can be acute, appearing immediately after delivery, or chronic, developing gradually over months or years. The earliest acute sign is the failure to lactate or an inability for the mother’s milk to “come in,” due to prolactin deficiency.
Chronic symptoms are often subtle and non-specific, making diagnosis difficult. Frequent signs include the cessation of menstrual periods (amenorrhea) due to a lack of FSH and LH, profound fatigue, unexplained weight gain, and intolerance to cold. These latter symptoms are indicative of secondary hypothyroidism caused by insufficient TSH.
The most serious consequence is the lack of adrenocorticotropic hormone (ACTH), leading to adrenal insufficiency and a deficiency in the stress hormone cortisol. This can manifest acutely as a life-threatening adrenal crisis, especially during times of physical stress, infection, or surgery.
Confirming the Condition
Diagnosing Sheehan’s Syndrome requires a detailed review of the patient’s medical history, focusing on complications involving severe blood loss during or after childbirth. Since symptoms mimic other common conditions, diagnosis relies on specific biochemical testing to confirm pituitary failure. Initial blood tests measure baseline levels of target hormones (cortisol, T4, estradiol) and pituitary hormones (ACTH, TSH, FSH, LH, and prolactin).
If baseline levels are low or inconclusive, dynamic or stimulation tests are ordered to assess the pituitary’s reserve capacity. For example, the ACTH stimulation test checks if the adrenal glands produce cortisol when prompted, indirectly evaluating the pituitary’s ability to release ACTH.
Imaging tests, most commonly Magnetic Resonance Imaging (MRI), are performed to visualize the pituitary gland. In the acute phase, the gland may appear enlarged, while chronic cases often show an atrophied or shrunken gland, sometimes presenting as an “empty sella.” Imaging also helps rule out other potential causes of hypopituitarism, such as a tumor.
Treatment and Lifelong Hormone Replacement
Treatment for Sheehan’s Syndrome involves lifelong replacement of the deficient hormones to restore normal body function and prevent serious complications. The sequence of replacement is carefully managed to avoid triggering an adrenal crisis. Glucocorticoids, such as hydrocortisone or prednisone, are the first and most important hormones replaced, as cortisol deficiency is immediately life-threatening.
Patients must practice “stress dosing,” which means temporarily doubling or tripling the glucocorticoid dose during periods of illness, fever, severe injury, or surgery. This adjustment mimics the body’s natural response to stress and prevents dangerous drops in blood pressure and blood sugar.
Thyroid hormone is replaced using levothyroxine, monitored via free T4 levels rather than TSH, since the signal from the damaged pituitary is unreliable. Sex hormone replacement, typically estrogen and progesterone, is necessary to regulate menstrual cycles, maintain bone density, and support overall health until the natural age of menopause. Growth Hormone replacement may also be prescribed to improve body composition, lipid profiles, and quality of life.