hormone measurements

Last reviewed 01/2018

The most important measurements are serum LH, FSH, PRL (x2) and TFTs.

LH is often raised in polycystic ovarian syndrome.

An elevated serum FSH indicates ovarian failure.

Prolactin is raised by stress, prolactinomas and secondary to some drugs e.g. phenothiazines.

A normal FSH may occur in conditions such as PCO, hypothalamic - pituitary lesions, and outflow tract disorders. A progesterone challenge will help discriminate these conditions. A withdrawal bleed after a progesterone challenge indicates anovulation e.g. PCO. No withdrawal bleed after a regime of oestrogen for 21 days then progestogen for 5 days indicates an outflow tract disorder e.g. Asherman's syndrome. A withdrawal bleed will occur after endometrial stimulation with oestrogens then a progestogen if there is a hypothalamic - pituitary lesion.

Measurement of plasma testosterone is indicated in amenorrhoea associated with hirsutism. Levels greater than 6 nmol/litre suggest ovarian malignancy which must be investigated further. An elevated LH/FSH ration with raised testosterone - but less than 6 nmol/litre - suggests polycystic ovarian syndrome.