Abstract: Based on thyroid screening program has been done by the Magelang District Health Office in 2012 it is known that pregnant women who have low levels of TSH 80/443 pregnancies. Low TSH is the result of an overactive thyroid gland or produce excessive thyroid hormones that circulate in the blood causing hyperthyroidism in pregnant women that can adversely affect the fetus one of which is the occurrence of low birth weight babies (LBW. Cases of low birth weight infants in the District Magelang has increased over the last three years ie in the year 2011 as many as 4.44% of cases, increased in 2012 as much as 5.03% of cases and by 2013 as many as 6.16% of cases.