To analyze the presentation, follow-up and evolution of differentiated thyroid cancer (DTC) detected during pregnancy.

Twenty nine women with DTC detected during pregnancy were analyzed. Group I (n = 13) was seen during pregnancy and DTC was diagnosed during gestation; detection of the nodule occurred during pregnancy (first trimester). Group II (n = 16) was seen after delivery; detection of the nodule occurred during pregnancy (second or third trimester). Complete thyroidectomy, ablative dose of radioactive iodine, and treatment with levothyroxine were performed. Follow-up: neck ultrasound; TSH, free T4, thyroglobulin, and anti-thyroglobulin antibodies with and without treatment with levothyroxine; and 131I whole body scans. Histological diagnosis, lymph node metastases, tumor size and stage, complications from pregnancy, and DTC evolution were evaluated.

100% of the patients had papillary thyroid carcinoma. Lymph node metastases were detected in 13 (44.8%), and invasion of adjacent extrathyroid tissue in 2 patients. Tumor size was larger in Group II: 22.1 ± 10.9 versus 13.9 ± 3.5 mm; p = 0.03. No differences were found in the tumor stages between groups. All patients had full-term pregnancies and healthy newborns. Follow-up: 5.7 ± 4.3 years; one patient had persistent disease.

DTC detected during pregnancy had a favorable evolution. Surgery may be postponed to the post-delivery period, unless there are risk factors that justify it during pregnancy.