| Domain | Key knowledge-base assertion | Suggested ontology terms/IDs | Evidence strength / limitations |
|---|---|---|---|
| Definition | Acquired postpartum hypopituitarism caused by ischemic necrosis or infarction of the pituitary, usually after severe postpartum hemorrhage with hypotension or shock. (pqac-00000000, pqac-00000002) | MONDO:0019618; Sheehan syndrome; acquired hypopituitarism; postpartum pituitary necrosis | Strong clinical and pathological consensus; predominantly observational evidence because the disease is rare. |
| Causal trigger | Severe obstetric blood loss and systemic hypoperfusion compromise perfusion of the pregnancy-enlarged pituitary. Possible modifiers include small sella, vasospasm, thrombosis, disseminated intravascular coagulation, and coagulation abnormalities; rare cases occur without recognized hemorrhage. (pqac-00000000, pqac-00000002) | Postpartum hemorrhage; hypovolemic shock; pituitary infarction; ischemic necrosis; term-name-only suggestions | Strong evidence for hemorrhage/hypoperfusion; modifier relationships are incompletely demonstrated and should not be encoded as independently sufficient causes. |
| Primary anatomy and cells | The anterior pituitary within the sella turcica is primarily injured; somatotroph, lactotroph, corticotroph, thyrotroph, and gonadotroph populations may be lost. Posterior-pituitary or stalk involvement is uncommon but can cause arginine-vasopressin deficiency. (pqac-00000003, pqac-00000004) | UBERON: pituitary gland, anterior lobe of pituitary gland, sella turcica; CL term-name-only: somatotroph, lactotroph, corticotroph, thyrotroph, gonadotroph | Cell types are inferred from axis-specific hormone loss and pathology; Sheehan-specific single-cell validation is unavailable. Exact UBERON/CL identifiers should be database-verified before ingestion. |
| Lactation phenotype | Failure to lactate or agalactia is a classic early clue reflecting prolactin deficiency; one cited clinical series reported absent postpartum milk production in about 70%. (pqac-00000008) | HP: Agalactia; HP: Hypoprolactinemia; exact IDs require verification | Common but not universal; frequency derives from older, referral-based cohorts and may not generalize. |
| Reproductive phenotype | Failure of menses to resume, secondary amenorrhea, infertility, loss of libido, and reduced axillary or pubic hair result from hypogonadotropic hypogonadism. Fertility can sometimes be restored with gonadotropin induction. (pqac-00000003, pqac-00000004) | HP: Secondary amenorrhea; HP: Female infertility; HP: Hypogonadotropic hypogonadism; HP: Decreased libido; term-name-only suggestions | Strong clinical association; reported frequencies vary with residual pituitary function and age at diagnosis. |
| Adrenal phenotype | ACTH deficiency causes fatigue, nausea, hypoglycemia, hypotension, hyponatremia, and vulnerability to life-threatening adrenal crisis during illness, procedures, or interruption of glucocorticoids. (pqac-00000002, pqac-00000007) | HP: Secondary adrenal insufficiency; HP: Hypotension; HP: Hypoglycemia; HP: Hyponatremia; HP: Adrenal crisis; exact IDs require verification | Strong clinical evidence; hyponatremia has been reported in approximately 33–69%, but estimates are heterogeneous. |
| Thyroid phenotype | Central hypothyroidism causes cold intolerance, dry skin, fatigue, bradycardia, weight change, and occasionally pericardial effusion or severe neuropsychiatric manifestations. One older series reported secondary hypothyroidism in 90%. (pqac-00000005, pqac-00000008) | HP: Central hypothyroidism; HP: Cold intolerance; HP: Dry skin; HP: Bradycardia; HP: Pericardial effusion; term-name-only suggestions | Strong axis-level evidence; individual manifestation frequencies are uncertain and severe cardiac presentations are mainly case-based. |
| Growth-hormone and metabolic phenotype | GH deficiency is frequent and contributes, with hypogonadism and glucocorticoid overtreatment, to reduced lean mass, increased adiposity, insulin resistance, dyslipidemia, low-grade inflammation, endothelial dysfunction, impaired bone health, and reduced quality of life. (pqac-00000000, pqac-00000001) | HP: Growth hormone deficiency; HP: Abnormal body composition; HP: Insulin resistance; HP: Hyperlipidemia; HP: Osteoporosis; term-name-only suggestions | Moderate evidence from small cohorts and extrapolation from hypopituitarism; causal contributions of individual hormone deficits are difficult to separate. |
| Posterior-pituitary phenotype | Central diabetes insipidus is rare but may present acutely with polyuria, hypernatremia, high serum osmolality, and dilute urine; it generally indicates extensive injury. (pqac-00000004) | HP: Central diabetes insipidus; HP: Polyuria; HP: Hypernatremia; HP: Decreased urine osmolality; term-name-only suggestions | Supported chiefly by case reports and a systematic review of rare cases; population frequency is not established. |
| Diagnostic laboratory evidence | Diagnosis requires compatible obstetric history plus biochemical evidence of one or more pituitary-axis deficiencies: low target-gland hormones with low or inappropriately normal pituitary hormones. Cortisol/ACTH, free T4/TSH, prolactin, IGF-1, LH/FSH with estradiol, serum sodium, and osmolality are core assessments. (pqac-00000001, pqac-00000003) | LOINC mappings should be assigned for each measured hormone after assay-specific review; SNOMED CT: hypopituitarism, central adrenal insufficiency, central hypothyroidism | Strong clinical practice basis, but no universally validated Sheehan-specific diagnostic criteria or single biomarker exists. Dynamic testing may be required for equivocal adrenal or GH function. |
| Imaging evidence | Acute MRI may show pituitary enlargement, abnormal signal, infarction, or absent enhancement; later evolution commonly produces pituitary atrophy and partial or complete empty sella. Normal early imaging does not exclude disease. (pqac-00000004, pqac-00000007) | UBERON: sella turcica, pituitary gland; RadLex/SNOMED CT: empty sella, pituitary infarction, pituitary atrophy; exact IDs require verification | Moderate evidence from serial case reports and cohorts; empty sella is supportive but neither necessary nor specific. |
| Treatment interventions | Replace glucocorticoids before levothyroxine when ACTH deficiency is possible; provide stress dosing and emergency education. Then individualize levothyroxine, estrogen–progestogen when appropriate, desmopressin for AVP deficiency, GH in selected adults, and gonadotropins for fertility. (pqac-00000001, pqac-00000003) | NCIT term-name-only: Glucocorticoid Replacement Therapy, Thyroid Hormone Replacement Therapy, Estrogen Replacement Therapy, Growth Hormone Replacement Therapy, Desmopressin Therapy, Ovulation Induction; CHEBI term-name-only: hydrocortisone, levothyroxine, estradiol, progesterone, somatropin, desmopressin | Standard-of-care principles are strong and largely extrapolated from hypopituitarism guidelines; Sheehan-specific randomized trials and response-rate estimates are lacking. Exact NCIT/CHEBI identifiers require verification. |
| Epidemiology | Incidence has fallen markedly where emergency obstetric care is accessible but remains under-recognized in lower-resource settings and migrant populations. Reported estimates include 5.1 per 100,000 population in Iceland and up to 3.1% among parous women in selected populations; estimates are not directly comparable. (pqac-00000000) | Epidemiological annotation: acquired rare disease; female reproductive/postpartum population | Low-to-moderate certainty because methods, denominators, eras, and ascertainment differ; global incidence and prevalence remain unknown. |
| Genetics and molecular profiling | Sheehan syndrome is acquired and has no established causal gene, Mendelian inheritance pattern, pathogenic variant, penetrance, carrier frequency, or validated protective allele. Coagulation or inflammatory polymorphisms have been explored only as susceptibility modifiers. No disease-defining epigenomic, transcriptomic, proteomic, metabolomic, single-cell, spatial, or integrated multi-omic signature is validated. (pqac-00000000) | MONDO:0019618; inheritance: not applicable; causal-gene field: none established; omics-biomarker field: unsupported | Strong evidence against treating it as a monogenic disorder; modifier studies are small and unreplicated, so variants should not be encoded as causal. |
| Immune mechanism | Ischemic necrosis may expose pituitary antigens and theoretically perpetuate damage through anti-pituitary or anti-hypothalamic immunity, but prospective postpartum-hemorrhage data found antibodies absent despite hypopituitarism. | GO term-name-only: immune response, inflammatory response, response to ischemia | Conflicting, low-certainty evidence; autoimmunity is a hypothesis or secondary modifier, not an established initiating cause or diagnostic biomarker. |
| Animal and experimental models | No well-established naturally occurring veterinary equivalent, breed association, zoonotic transmission, or validated genetic model was identified. General hemorrhagic-shock, pituitary-ischemia, hypophysectomy, and hormone-deficiency models can investigate downstream biology but do not fully recapitulate pregnancy-associated human disease. | NCBI Taxonomy/VBO/OMIA fields: no supported disease-specific entry identified; model type: induced physiological model, term-name-only | Major evidence gap. Model claims require species- and protocol-specific primary validation before knowledge-base inclusion. |


*Table: Compact ontology-ready assertions spanning causation, anatomy, phenotypes, diagnosis, treatment, epidemiology, molecular evidence, and models. Unverified ontology identifiers and unsupported knowledge fields are explicitly distinguished from established evidence.*