Endocrinologic Disorders of Pregnancy

During pregnancy, an increase in hCG stimulates the TSH receptor causing increased production of free T4, free thyroxine. Increased thyroid hormone production stimulates the negative feedback loop, resulting in decreased TSH. ACTH rises in proportion to increasing cortisol level in pregnancy. Contra-insulin hormones (estrogen, cortisol, and human placental lactogen) are usually produced after the 24th week of gestation, therefore screening for gestational diabetes should occur between 24 and 28-weeks gestation.