Thyroid Nodular Disease and Thyroid Cancer During Pregnancy

Abstract

The identification of clinically relevant thyroid nodules occurs frequently during pregnancy. Most nodules are asymptomatic and simply detected during a time of increased medical care. Initial evaluation of clinically relevant thyroid nodules identified during pregnancy generally does not differ from assessment performed in nonpregnant individuals, excepting the use of diagnostic molecular tests, or the administration of radiopharmaceuticals. Ultrasound and ultrasound-guided fine needle aspiration (UG-FNA) can be safely performed during pregnancy and provide important information regarding thyroid cancer risk. The approach to thyroid surgery during pregnancy, however, is most often conservative. Most thyroid nodules with malignant or indeterminate cytology detected during pregnancy will not grow nor pose significant risk during a 6–12 month delay in treatment. In contrast, thyroid surgery in pregnant women is higher risk in comparison to nonpregnant women. Therefore, the decision to pursue thyroidectomy must be individualized, weighing the risks and benefits of any intervention against those of conservative monitoring. In rare circumstances, high-risk scenarios necessitate thyroidectomy during pregnancy. When required, thyroid surgery is generally recommended before 24–26 weeks of pregnancy and should be performed by thyroid surgeons with a high degree of experience. Thyroid hormone concentrations should be assessed preoperatively and monitored closely postoperatively, acknowledging an increasing demand for thyroxine that occurs throughout gestation. Maternal serum TSH concentrations should be regularly assessed during the first half of pregnancy, with levothyroxine doses adjusted upward to maintain a TSH target below 3.0 mIU/L. In conclusion, through a balanced and informed approach to the clinical care of this unique population, outcomes can be optimized for both the mother and the fetus.