The Influence of the Antithyroid Drug, Propylthiouracil, on Gestation and Lactation in Rats

The anti-thyroid drug, propylthiouracil (PTU), when fed to female rats at the dietary level of 0.1% has a slight effect on the average number of young per litter if administered during the preconception period or gestation but if administered continuously during these periods results in a much lower litter size. PTU treatment of mothers during lactation results in cretin-like young and poor survival rates during lactation and after weaning. Ratios of thyroid weight to body weight indicate transfer of PTU to young during gestation and lactation