# Sheehan Syndrome

> Sheehan syndrome for NEET-PG Medicine, covering postpartum pituitary necrosis, failure of lactation, the order of hormone losses and replacement priorities.

- Canonical URL: https://prepelephant.com/topics/neet-pg/medicine/sheehan-syndrome
- Exam / course: NEET-PG · Subject: Medicine
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-14
- Last updated: 2026-10-14
- Reference basis: Williams Obstetrics; Williams Textbook of Endocrinology
- How to cite: "Sheehan Syndrome", PrepElephant, https://prepelephant.com/topics/neet-pg/medicine/sheehan-syndrome

## Direct answer

Sheehan syndrome is postpartum necrosis of the anterior pituitary, caused by severe haemorrhage and hypotension during or after delivery. The pituitary enlarges in pregnancy and is vulnerable to ischaemia, and failure of lactation is often the first clue. Hypopituitarism then develops gradually, and glucocorticoid cover must always precede any thyroid hormone replacement.

## What you must remember

- **Mechanism:** the pituitary enlarges in pregnancy, so severe postpartum haemorrhage with shock can cause infarction of the gland.
- **Early clue:** failure of lactation after delivery, often with absent menses, which may go unrecognised for months.
- **Gonadotrophin loss:** amenorrhoea and loss of pubic and axillary hair, the latter partly from adrenal androgen loss.
- **Hormone sequence:** gonadotrophin and growth hormone losses usually come first, with TSH and ACTH deficiency following later.
- **Diabetes insipidus:** rare, because the posterior pituitary has a separate blood supply from the inferior hypophyseal artery.
- **Adrenal crisis:** ACTH deficiency can present with hypotension, hyponatraemia and hypoglycaemia during stress, and this is life-threatening.
- **Replacement order:** hydrocortisone first, then levothyroxine, then oestrogen and progestogen, with growth hormone when indicated.

## Tracing hormone failure back to the delivery

A woman who did not lactate after a bleeding delivery may present months later with tiredness and amenorrhoea. The workup confirms multiple axis failure before treatment is planned.

1. **Take the obstetric history:** postpartum haemorrhage, shock or transfusion is central to the diagnosis, and it is often recalled only when asked.
2. **Measure the target hormones:** 8 am cortisol with ACTH, free T4 with TSH, LH, FSH, oestradiol and prolactin.
3. **Assess adrenal reserve carefully:** a short synacthen test can look normal early in ACTH deficiency, so dynamic results are interpreted with care.
4. **Image the pituitary:** MRI may show a small or empty-looking sella, which supports the diagnosis but does not replace hormone testing.
5. **Start glucocorticoid cover first:** hydrocortisone is started before any thyroid hormone, since thyroxine speeds cortisol clearance and can precipitate crisis.
6. **Replace sex steroids and review:** oestrogen with progestogen restores menses and bone health when pregnancy is not wanted, while gonadotrophin therapy is used for ovulation induction when it is.

## High-yield traps for viva and paper

Examiners test the same few points about this condition.

- **Trap:** expecting diabetes insipidus as a common feature. — **Correct:** the posterior pituitary is usually spared, so polyuria is unusual and points to another cause.
- **Trap:** starting thyroxine first for low free T4. — **Correct:** hydrocortisone comes first, because thyroid hormone raises cortisol clearance and can precipitate adrenal crisis.
- **Trap:** expecting lactation to return with treatment. — **Correct:** the prolactin-producing tissue is lost, so hormone replacement corrects the deficits but cannot restore milk production.

## Frequently asked questions

### What is the classic presenting feature of Sheehan syndrome?

Failure of lactation after delivery is the classic presenting feature of Sheehan syndrome. Women often also have amenorrhoea, fatigue and loss of pubic and axillary hair. The diagnosis may be made months or years after the delivery, when symptoms of hypopituitarism appear.

### Why is diabetes insipidus uncommon in Sheehan syndrome?

Diabetes insipidus is uncommon in Sheehan syndrome because the posterior pituitary receives its blood supply from the inferior hypophyseal artery, separate from the anterior pituitary. Ischaemic necrosis therefore mainly affects the anterior lobe. Polyuria in a woman after delivery should prompt a search for another cause.

### Which hormone should be replaced first in Sheehan syndrome?

Glucocorticoid replacement with hydrocortisone should be started first in Sheehan syndrome, before thyroxine. Thyroid hormone increases cortisol clearance and can precipitate adrenal crisis in untreated ACTH deficiency. Sex steroid and growth hormone replacement follow once the patient is stable.

### Can lactation return with treatment in Sheehan syndrome?

Lactation does not usually return in Sheehan syndrome, because the prolactin-producing tissue is lost to ischaemic necrosis. Hormone replacement treats the endocrine deficits but cannot restore milk production. Fertility may be restored with gonadotrophin therapy if pregnancy is desired.