Case Report of Postpartum Thyroid Nodule Size Reduction

Introduction: Thyroid nodules are very common. They occur more commonly in women with an increased prevalence of thyroid nodules reported in pregnancy. Most thyroid nodules diagnosed during pregnancy are benign. Pregnancy causes major physiological changes including changes in the levels of thyroid hormones and the elevation of thyroid binding globulin. Thyroid nodules may also occur in people with abnormal thyroid function tests manifesting as hyperthyroidism or hypothyroidism. We present a unique case of a new diagnosis of a large thyroid nodule that has significantly decreased in size after 20 months postpartum. Case description: Patient is a 31 year old female with past medical history of anxiety and white coat hypertension who was diagnosed with a 3.3 x 2.3 x 2.1 cm thyroid nodule a month following delivery. Patient did not have any abnormalities in her thyroid function tests before, during, or after pregnancy. She remained euthyroid throughout the pregnancy and in the postpartum period. Fine needle aspiration biopsy of the nodule showed atypia of undetermined significance (Bethesda Category III). The specimen was further analyzed by afirma testing that confirmed benign pathology. Twenty months postpartum, the thyroid nodule significantly decreased in size to 1.9 x 1.4 x 1.2 cm. Conclusion: Thyroid hormone levels physiologically change during pregnancy and this may affect the growth of thyroid nodules. We just presented a patient who exhibited a significant decrease in the size of her thyroid nodule. Sahin et al. showed that while the size of the thyroid nodule increases during pregnancy the number of nodules remains unaffected. Kung et al. showed that pregnancy is associated with an increase in the size of preexisting thyroid nodules as well as the number of newly developed thyroid nodules. Vanucchi et al. showed that although the thyroid gland becomes larger, particularly in late pregnancy, the sizes of any preexisting thyroid nodules remained unchanged and patients’ thyroid gland size returned to normal after delivery. The current literature provides conflicting data on this topic. The true association between pregnancy and thyroid nodules is unknown. Contemporary literature is ambiguous on this topic and more scientific studies are required to find the true association between pregnancy, the formation of thyroid nodules, and increase in the size or number of thyroid nodules.