Intellectual development in children whose mothers received propylthiouracil during pregnancy.

Standard intelligence tests were administered to twenty-eight children who had been exposed to PTU in utero and thirty-two non-exposed siblings. There was no significant difference in results between the two groups. The present study suggests that with careful attention, pregnant women with thyrotoxicosis can be treated with propylthiouracil without interfering with subsequent intellectual development in the offspring.