Thyroid nodules are common in pregnant women. Most of them are benign. Toxic autonomous nodules may be seen infrequently, and the diagnosis is supported by elevated free thyroid hormone levels and undetectable levels of TSH. The most common and most important problem is the diagnosis of thyroid cancer. FNB is the most reliable diagnostic tool. FNB findings also can be used to indicate the urgency for surgery and the appropriate extent of the operation when surgery is indicated. Best use of FNB data requires that the cytopathologist provide tissue diagnoses and that there has been enough experience to permit reasonable inferences of cancer probability for each diagnosis.