Selenium and Thyroid dysfunction

Selenium supplementation during pregnancy and after pregnancy reduces the occurrence of thyroid dysfunction and hypothyroidism in the post partum state (After delivery). This research data has been published in the “Journal of Clinical Endocrinology and Metabolism”.

Researchers from centers in Italy carried out the prospective, randomized placebo controlled study of participants age 18 to 36. Participants with thyroid peroxidase antibodies were divided into the groups getting Selenium or placebo. The treatment group was assigned to receive Selenomethionine 200 mcg daily. A control group composed of 85 females without thyroid peroxidase antibodies.

Thyroid function tests were performed at twenty and thirty weeks of pregnancy, at delivery and at one, two, five, nine and twelve months after delivery. During pregnancy, the treatment group had thyroid stimulating hormone levels of 1.6 and the placebo group had thyroid stimulating hormone levels of 1.7. Thyroid stimulating hormone levels in the control group were 0.9.

Two months after delivery, 5.2% of patients in the treatment group and 6.8% in the placebo group were hypothyroid. Within twelve months of delivery, 28.6% of patients in the treatment group had thyroid dysfunction and 11.7% were permanent hypothyroid. In the placebo group, 48.6% had thyroid dysfunction and 20.3% were permanently hypothyroid. In the control group, 3.7% of patients had thyroid dysfunction.

Thyroid peroxidase antibody titers during pregnancy were reduced by 62.4% in the treatment group and 43.9% in the placebo group. Peak titers during the post partum period were more than two times lower in the treatment group as compared with the placebo group.

Selenium concentrations were similar in all three groups at ten weeks pregnancy, but were higher in the treatment group compared to the placebo and the control groups at each subsequent testing point after pregnancy.

Previous studies have demonstrated that selenium supplementation may decrease chronic inflammation of the thyroid, but this is the first study in which selenium was administered in pregnant women. Dr. Robert Negro from The Department of Endocrinology at V, Fazzi Hospital in Italy believes that cost and efficacy evaluation and different dosage in investigation of selenium are necessary. However, this study results represents an important first step.