Normal values of thyroid stimulating hormone during pregnancy

Normal TSH levels for pregnant women are different from those for the general population. The guidelines recommend that each region establish its own regional TSH level for pregnancy. If no regional TSH level is established, it can be measured as a cutoff for pregnancy of less than 4.0 or as a 22% drop in the upper limit of normal for the general population. If a pregnant woman's TSH is above 78% of the normal maximum, it is an elevated TSH, indicating a relatively low thyroid function, called gestational hypothyroidism. It can also be simply judged that the normal TSH level in the first trimester is 0.1 to 2.5; the normal TSH level in the second trimester is 0.2 to 3; and the normal level in the third trimester is 0.3 to 3.5.