Thyroid secretions in adequate amounts appear to be essential for development of the egg and for proper ovarian secretions. If thyroid function is low, an egg may be discharged from an ovary but it may not be fertilizable or, if fertilized, may not be capable of nesting so that pregnancy is quickly aborted.

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.

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.

Forty years ago, after many years of successful use of thyroid therapy, leading gynecologists in this country and elsewhere were reporting thyroid had cured more menstrual disorders than all other medications combined. Unfortunately, that lesson seems to have been largely lost.

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.

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.

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.