This describes anterior pituitary infarction from severe obstetric shock and postpartum haemorrhage. It is a rare cause of hypopituitarism. It occurs in 1 in 10 000 pregnancies.
In late pregnancy, the anterior pituitary is particularly susceptible to the effects of ischaemia as it may be greatly enlarged from hyperplasia and hypertrophy of the lactotrophs. Postpartum haemorrhage causes rapid depletion of blood volume and systemic hypotension. The blood supply to the anterior pituitary is arrested and infarction ensues. In rare cases, the posterior lobe also may be involved.
The endocrine presentation is variable. Failure of lactation, fatigue, loss of vigour and failure to resume menstruation are common. In time, there is loss of sexual hair from the pubic and axillary areas. Posterior pituitary involvement may result in diabetes insipidus. However, up to 70% of the anterior pituitary mass may be lost without symptoms.
It is the only condition of clinical significance associated with a low serum prolactin - less than 5 ng per ml.
The condition is effectively treated by appropriate hormone replacement.