Description

• Sheehan syndrome is a rare disorder of postpartum panhypopituitarism occurring secondary to ischemia and subsequent necrosis of the pituitary gland, classically associated with severe postpartum hemorrhage.
• It is often recognized early postpartum when there is lack of milk production and amenorrhea; however, may be upward of 20 years until diagnosis and symptomatology can be variable depending on associated hormonal deficiencies
• Deficiencies in some or all pituitary-regulated hormones may develop and may be complete or partial. The syndrome may be associated with hypocortisolism, hypothyroidism, hypogonadism, and loss of growth hormone (GH) and prolactin (PRL) to varying extents for each (1). More rarely, diabetes insipidus may occur (2).
• System(s) affected: endocrine, reproductive
• Synonym(s): postpartum pituitary necrosis; postpartum hypopituitarism; postpartum anterior pituitary necrosis

Epidemiology

• Sociocultural disparity—more common in resource-poor countries, particularly because of the prevalence of home births. It is less common in high resource or developed nations (e.g., United States). However, the diagnosis is more likely to be missed or delayed in high-resource countries given the rarity of the syndrome.
• Predominant age: childbearing years
• Predominant sex: female only

Incidence
One study in Spain found incidence of panhypopituitarism to be 46/100,000 per year in general, with only a fraction due to Sheehan syndrome (2), whereas other literature quotes an incidence of 1/10,000 per year (3).

Prevalence

• Prevalence of hypopituitarism is 20 to 455 per 100,000, with few cases attributed to Sheehan syndrome.
• One study estimated the prevalence of Sheehan syndrome (1) to be 3.1% in parous women >20 years old, noting that 2/3 delivered at home (2).

Etiology and Pathophysiology

• Postpartum hemorrhage results in decreased intravascular volume and hypotension, leading to ischemia of various organs, including the pituitary gland, which is enlarged in pregnancy and more reliant on blood flow.
• Ischemia to the pituitary gland results in necrosis and dysfunction.
• Hormones dependent on pituitary synthesis and/or regulation, such as glucocorticoids, thyroid hormone, GH, PRL, and gonadotropins (LH and FSH), become deficient resulting in the clinical syndrome.

Genetics
None known

Risk Factors

• Sheehan syndrome is associated with postpartum hemorrhage which may occur in any woman. Factors that increase postpartum hemorrhage risk include but are not limited to:
  • Macrosomic neonate
  • Multiple gestation (twins, triplets, etc.)
  • Prolonged or augmented labor
  • Placental disorders: abruption, accreta, previa
  • Retained placenta
  • Soft tissue lacerations
  • Maternal blood disorders
  • Hypertensive disorders including preeclampsia
  • Chorioamnionitis
  • Obesity
• Lack of access to adequate obstetric care is also a risk factor and thus risk is increased with home deliveries and in resource-poor countries.

General Prevention

• As Sheehan syndrome is associated with postpartum hemorrhage and postpartum hemorrhage is associated with interventions, avoid interventions when possible (e.g., augmented labor, episiotomy, forceps or vacuum delivery, and cesarean section), consistent with good obstetric practice.
• Address or limit modifiable risk factors associated with postpartum hemorrhage, including obesity.

Commonly Associated Conditions

Postpartum hemorrhage