Sheehan’s syndrome, or the so-called postpartum ischemic necrosis of the pituitary gland, is a pathological condition with a frequency of 1 in 10,000 births, which proceeds clinically with a picture of primary hypopituitarism. The cause of necrosis of the pituitary gland is severe blood loss that occurred during or after childbirth. Nowadays, the possibility of rapid and adequate blood replacement reduces the incidence of this syndrome. The pituitary gland is a gland located in the sella turcica of the sphenoid bone. It consists of two lobes – an anterior lobe (adenohypophysis) and a posterior lobe (neurohypophysis). The pituitary gland weighs about 0.6 grams, but increases in size during pregnancy. With severe postpartum hemorrhage, hypotension occurs, reducing the circulating blood volume, as a result of which tissue ischemia occurs. The pituitary gland is particularly sensitive to ischemia, which subsequently necrotizes. Severe blood loss, which can lead to the development of Sheehan’s syndrome, can occur in the following pathological complications of pregnancy: 1. Placenta praevia – i.e. located in the lower uterine segment, partially or completely covering the internal cervical opening. Several forms are distinguished – low-lying, marginal, isthmic-cervical, partial and total, as the exact reason for the occurrence of this complication is not fully understood; 2. Abruptio placentae – complete or partial detachment of the placenta. One of the most common causes of placental abruption is preeclampsia; 3. Partus abnormalis – assisted birth, in which forceps or a vacuum extractor are used; 4. Birth of a large fetus (weight over 4000 g) or multiple pregnancy. In addition to severe blood loss, the cause of Sheehan’s syndrome can be increased metabolic needs and increased sensitivity to hypoxemia, blood coagulation disorders, hyperplasia of lactotrophs, systemic diseases. It is characteristic of postpartum necrosis of the pituitary gland that it can appear both immediately after birth and years later. The secretion of hormones from the anterior lobe of the pituitary gland is mainly affected – there is no production of prolactin, thyroid-stimulating hormone (TSH), adenocorticotropic hormone (ACTH), somatotropin, gonadotropins – follicle-stimulating hormone (FSH) and luteinizing hormone (LH). In the first days after birth, a severe, uncontrollable headache, nausea, vomiting and low blood pressure may occur. More characteristic symptoms of Sheehan’s syndrome are: 1. Suppressed lactation – the lack of prolactin is the reason for the inability to breastfeed. In patients with a slower evolution of the disease, there are no difficulties with lactation; 2. Amenorrhea – due to the missing secretion of gonadotropins. Atrophy of the mammary glands and loss of libido also occur. In some patients with partial necrosis of the pituitary gland, it is possible to have no disturbances in the menstrual cycle; 3. Hypothyroidism – the levels of thyroxine and triiodothyronine decrease, which is why patients complain of easy fatigue, dry skin, hair loss, depression,weight gain; 4. Premature aging, hypopigmentation, hair thinning; 5. Hyponatremia – the most common disorder in the electrolyte balance; 6. Development of diabetes insipidus – although less often, the neurohypophysis and its function may be affected. Antidiuretic hormone (ADH) secretion is suppressed, leading to polyuria, polydipsia and electrolyte disturbances. Diagnosing Sheehan syndrome can be a difficult task. The main diagnostic method is nuclear magnetic resonance or pituitary scan. Serum levels of hormones produced by the anterior pituitary gland are tested. Based on the results of these tests and the data from the anamnesis, a diagnosis is made. Treatment for postpartum pituitary necrosis is hormone replacement—synthetic thyroxine to treat hypothyroidism; estrogens and progesterone to regulate the menstrual cycle; gonadotropins, FSH and LH, to stimulate ovulation; growth hormone; corticosteroids to control secondary adrenal hypofunction. If left untreated, Sheehan syndrome is a life-threatening condition. Complications may include extreme lowering of blood pressure, Addison’s crisis, and death. For this reason, early and timely replacement treatment is extremely important for the prognosis.