In study at the Mayo Clinic covering fifty consecutive young women with hypothyroidism, twenty-eight has menstrual disturbances. Abnormally profuse menses was a common disturbance; frequent bleeding between periods was another; in some cases, both problems were present. Thyroid therapy relived the disturbances.

On thyroid therapy, more than 90 percent of those with painful menstruation were relieved, most of them completely. The results were fully as good in converting irregular periods to normal, regular ones. And in six of seven women with excessive flow, normal flow was established.

The medical literature is full of reports going back many years that provide evidence that thyroid medication, used when indicated, is one of the most helpful measures in the treatment of infertility in both men and women. And not infrequently it may be needed by both partners in an infertile marriage.

Many of the women who benefited from thyroid therapy provided added evidence that it was the thyroid which was responsible. There were the women who, upon being relieved of their {menstrual} problems, stopped taking medication only to return in a few months with their original complaints. Thyroid therapy again overcame their difficulties.

Certainly miscarriage is not invariably related to low thyroid function. There are many other possible causes. Yet soon after thyroid therapy first became available, it was found that patients with a history of miscarriages often had a history compatible with thyroid deficiency and that full-term pregnancies might follow treatment with thyroid.

But the problem remains two fold: the need for recognition that low thyroid function very often can provoke menstrual problems, and the need for recognition, too, that hypothyroidism may be present despite laboratory tests suggesting it is not.

From what has been said, it would appear that the possibility of thyroid deficiency should be considered, and if found, should be treated in any woman with a menstrual abnormality or a reproductive problem. It was generally agree that correction of thyroid deficiency solved many such abnormalities and problems - until about 1940.