Thyroid function in women with premenstrual syndrome

We have examined the relationship between thyroid function and the presence of symptoms in women with prospectively confirmed premenstrual syndrome (PMS) in the following ways: 1) basal thyroid function tests (n = 124); 2) thyroid auto-antibody levels (n = 63); 3) TRH stimulation tests performed during the follicular phase (n = 39) or during both the follicular and luteal phase (n = 21); and 4) the efficacy of L-T4 in the treatment of PMS (n = 30).

Thirteen women (10.5%) had basal evidence of either grade I or II hypothyroidism or hyperthyroidism. Elevated thyroid auto-antibody titers were observed in eight women (13%). Eighteen women (30%) (all with normal basal TSH levels) had abnormal responses to TRH, either blunted (n = 6) or exaggerated (n = 12). L-T4 was not superior to placebo in the treatment of PMS in a double blind placebo controlled cross-over trial. Although it is clear that PMS is not simply masked hypothyroidism, abnormalities of stimulated thyroid function appear with greater than expected frequency in women with PMS and may define a subgroup of women with this disorder. L-T4 supplementation appears to have no place in the routine management of PMS.