Curriculum · Gynecology / Women's Health / Infertility / Perinatal Care / Birth Spacing
Sheehan syndrome
What it is
Sheehan's syndrome occurs after delivery due to severe bleeding. It is listed as a pituitary dysfunction, inside the hypogonadotropic hypogonadism group where FSH and LH are low and estrogen is low, and it sits there with craniopharyngioma, hyperprolactinemia and hypothyroidism.
Causes and risk
The event before it is bleeding at delivery. Postpartum hemorrhage is a loss of more than 500 ml after normal vaginal delivery and more than 1000 ml after cesarean section. Primary PPH occurs within 24 hrs of delivery and is due to an atonic uterus, while secondary PPH occurs after 24 hrs and up to 6 weeks and is due to retained placental bits and infection.
How it presents
The presentation is read off the pituitary hormones that are lost: failure of lactation from a low prolactin, cold intolerance from a low TSH, and no pubic hair from a low ACTH. Because FSH and LH fall too, Sheehan's syndrome appears in two amenorrhea lists at once. It is among the pituitary causes of primary amenorrhea with absent secondary sexual characteristics, where the absence of estrogen gives underdeveloped breasts and absent axillary and pubic hair. It is also among the causes of secondary amenorrhea, where it stands with prolactinoma under pituitary dysfunction. Secondary amenorrhea itself means no menses for 3 months if the cycles were regular, or no menses for 6 months if they were irregular. The endocrine summary lays the features out hormone by hormone, and reading them that way is what turns a vignette into the diagnosis: lactation failure from a low prolactin; amenorrhea, hot flashes and vaginal atrophy from low FSH and LH; fatigue and bradycardia from a low TSH; anorexia, weight loss and hypotension from a low ACTH; and decreased lean body mass from a low growth hormone. The pathogenesis is put in two lines above that list, obstetric hemorrhage complicated by hypotension and then postpartum pituitary infarction, and because the infarction takes the gland itself all the pituitary hormones are decreased together. Lactation failure is the first of those features, so a woman who bled at delivery and then could not feed her baby is presenting with it, and the rest of the list is what to ask her about.