This case report illustrates an exceptional clinical situation in which a pregnant woman abruptly presented, at 5 months' gestation, with major swelling of the thyroid gland that led to respiratory symptoms and emergency hospitalization. The medical condition was shown to be caused by acute intrathyroidal hemorrhage within a preexisting-albeit until then unnoticed-multinodular goiter. The cause of the intrathyroidal hemorrhage could not be firmly delineated, although it remains possible that an unusual extraneous cause constituted a "trauma" that triggered this rare medical condition.