Iodine supplementation during pregnancy

INFLUENCE OF IODINE SUPPLEMENTATION DURING PREGNANCY AND LACTATION ON THYROID SIZE IN WOMEN. 

These results indicate that the basic iodine intake during pregnancy is considerably below recommended levels - with moderate geographical variation. lo ne supplementation during pregnancy and lactation is not taken regularly. 

To evaluate if iodine supplementation during pregnant and lactation induced measurable effects on the thyroid a prospective randomized study was performed in the Randers area (9). Normal pregnant women (n=54) received +/- 200 Mg iodine supplementation per day from week 18 of pregnancy until 12 months after delivery. Thyroid volume was measured by sonography. 

To evaluate the effect of iodine or thyroxine supplementation during pregnancy, the thyroid volume and function were determined at the beginning (11. week of gestation) and at the end of pregnancy (two weeks post partum) in the following groups of mothers 16 without any treatment (I), 5 with iodine (300 pg/d) (II), and 4 with thyroxine (100 pg/d) supplementation (III). 

Other treatment options, besides thioamide therapy, involve RAI. The iodine 131 isotope is taken up by the thyroid gland and the radioactivity destroys the gland. RAI is safe, pain free, easy to administer, and very effective. RAI may result in euthyroidism but more frequently results in hypothyroidism requiring lifelong levothyroxine supplementation. RAI should never be given during pregnancy since it crosses the placenta. 

It has been recommended that iodine be added to all prenatal vitamins (National Academy of Sciences, 2003) and that women receive 150pg iodine supplements daily during pregnancy and lactation (Becker et at, 2007 Zimmermann and Delange, 2004). 

Iodine deficiency at any degree of severity causes maternal and fetal hypothyroxinemia. As thyroid hormones of the mother and the fetus must be kept at optimal levels, iodine prophylaxis should be provided, especially in iodine deficient areas. To establish normal fetal brain development, iodine supplementation must be started before pregnancy and should be continued during the gestational period. 

In countries with well-established universal salt iodization (USI) programs and iodine sufficiency, pregnancies probably are not at risk of iodine deficiency. In countries without USI programs and mild ID (most European countries), supplementation can be achieved with 100—200p,g of iodine per day given during pregnancy. 

Supplementation of iodine during pregnancy is recommended to eliminate iodine-deficiency diseases, especially cretinism in iodine deficiency areas. However, for pregnant women who lived in iodine-excess areas or were exposed to iodine-containing medication during pregnancy, the total iodine intake and their TH status should be closely monitored. 

Another area of focus was pregnant women and their newborn (Pedersen et aL, 1990, 1993 Nohr et aL, 1993, 1994). Women not receiving iodine supplements had a gradual increase in serum TSH during pregnancy (Weeke et aL, 1982) that was prevented by iodine supplements (Pedersen ij /., 1993). 

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