Iodine deficiency (ID) during pregnancy causes several adverse health effects for both mother and child. Salt iodization programs may fall short in covering the iodine requirements of pregnant women. Daily iodine supplementation in pregnancy is widely recommended, but the long-term benefits and safety of iodine supplementation in mild-to-moderate ID pregnant women is uncertain.
To address this, an iodine supplementation trial was conducted in mildly ID pregnant Thai women between 2008 and 2013. The results indicate that maternal iodine supplementation is safe and effective in normalizing iodine intake of the mothers. However, routine iodine supplementation is not necessary in mildly ID pregnant women from areas with effective iodized salt programs. This may be attributed to adequate iodine stores accumulated before pregnancy, which can contribute to iodine requirements during pregnancy. Furthermore, body weight of pregnant women (especially overweight) should be monitored, since this was found to be associated with thyroid dysfunction and unfavourable birth outcomes.