Thyroid function and treatment in premenstrual syndrome

Area of Science:

• Endocrinology
• Women's Health
• Reproductive Medicine

Background:

• Previous research suggested a link between premenstrual syndrome (PMS) and thyroid hypofunction (TH), with L-T4 therapy reportedly relieving symptoms.
• This hypothesis proposed subclinical hypothyroidism as a common cause of PMS.

Purpose of the Study:

• To investigate thyroid function in women diagnosed with PMS.
• To evaluate the efficacy of levothyroxine (L-T4) therapy in managing PMS symptoms compared to a placebo.

Main Methods:

• A double-blind, placebo-controlled study was conducted.
• Thyroid function tests (T4, T3 uptake, T3, TSH, TRH stimulation test) were performed on 15 normal women and 44 women with PMS.
• 22 PMS women received L-T4 (1.6 mcg/kg/day), and 22 received a placebo for 2 months.

Main Results:

• No significant evidence of thyroid dysfunction was found in the PMS group.
• Symptom relief in the L-T4 group (27% complete, 27% partial, 54% some relief) was not significantly different from the placebo group (45% complete, 23% partial, 68% some relief).
• The previously reported high incidence of TH in PMS may be due to variations in the normal range for TSH levels in TRH stimulation tests.

Conclusions:

• There is no significant association between thyroid disease and premenstrual syndrome (PMS).
• Levothyroxine (L-T4) treatment is not more effective than placebo for alleviating PMS symptoms.
• The interpretation of TRH stimulation tests may require re-evaluation for diagnosing thyroid issues in PMS patients.