How do we interpret these reports?

Many physiological changes occur in pregnancy which can cause changes to the parameters, which we normally use to assess thyroid status. Serum TSH levels may be below the nonpregnant reference range in the first half of a normal-term pregnancy, presumably the result of stimulation of the normal thyroid by high levels of serum hCG. Serum total T4 and total T3 levels increase in pregnancy due to the effect of increased estrogen on the thyroid binding globulin. Hence, in pregnancy, the normal limit for total T4 and T3 values are 1.5 times the non-pregnant range.

So this patient’s reports appear normal and the changes represent the physiological changes of pregnancy, a free T4 is ordered which was in the normal limit. Hence, she is followed up and her repeat TSH at 5 months is 1.2 mIU/mL.