The possible relationship between menorrhagia and occult hypothyroidism in IUD-wearing women.

Abstract

A high incidence of occult hypothyroidism in menorrhagic women has been reported and emphasized in recent studies. In order to verify this statement, we have evaluated the functional status of the thyroid gland in intrauterine device (IUD) wearers suffering from increased menstrual bleeding. The study group consisted of 40 IUD-wearing women, aged 26-46 years, suffering from metrorrhagia. The control group consisted of 38 IUD-fitted women, 22-44 years old, in whom menstrual bleeding was not significantly increased. Menorrhagia was defined as excessive vaginal bleeding lasting for 6 days or more, and/or containing a significant amount of blood clots. Free thyroxine (FT) and thyroid-stimulating hormone (TSH) levels were assessed. FT levels were identical in both groups and within the normal range (1.31 +/- 0.28 ng/dl). TSH levels were significantly higher in the study group than in the controls, although they remained within the normal range (2.75 +/- 2.06 vs. 1.45 +/- 0.45 microU/ml, p < 0.01). A thyrotropin-releasing hormone (TRH) test was performed in 10 women having the highest TSH levels. All the results of TRH tests were consistent with occult hypothyroidism. These women were treated with L-thyroxine and all had a significant improvement in their bleeding within 3 months of treatment. We concluded that any IUD-wearing woman suffering from menorrhagia may have occult hypothyroidism. Should FT and TSH be within normal limits, a TRH test should be performed as the definitive diagnostic test. A frequent side-effect of intrauterine contraception is menometrorrhagia. The intrauterine device (IUD) has to be removed in 5-15% of cases to prevent iron deficiency anemia.