A 30-year-old woman comes to the office because she ...
Abnormal brain development
I don't understand the last part of this question stem though... if the mother's TSH *increases* during pregnancy? Wouldn't this further increase her (and/or the fetus's) production of T4 and thus counteract the hypothyroidism?
@neonem no. Autoimmune hypothyroidism is a destruction of the thyroid gland, and a decrease in production of T3/T4.
An increase in TSH means that there is not enough T3/T4 to inhibit TRH, and so TSH is being released to stimulate the thyroid gland.
TSH, T3, T4 and thyroglobulin cannot cross the placental barrier.
@arezpr although those hormones can't cross, the autoantibodies from Hashimoto's can
The baby has its own TSH though
TSH comes from the pituitary, and act on the thyroid. Autoantibodies attack the thyroid, so TSH doesn't work.
I think that this question is phrased atrociously,
Just like the rest of the NBME
I agree, the article you linked states "signs of fetal hyperthyroidism such as tachycardia, intrauterine growth retardation, cardiac failure, and the development of fetal goitre"
I chose answer E during the exam - "Thyroid gland enlargement"
Still trying to understand how they linked cretinism to a case where the mother's hypothyroidism was well controlled, and then asked for the sequelae if her TSH increased. Maybe increased TSH is supposed to indicate worsening hypothyroid - low T3/T4 needing to be stimulated by TSH?