Pre-20th century evidence for the placental passage of drugs

As early as the 19th century, research was being conducted on the passage of foreign material across the placenta from mother to offspring. The evidence resulting from these studies, while not always conclusive, should have prompted 20th century pharmaceutical companies to test new drugs for teratogenic activity if they were to be prescribed to women who were likely to become pregnant. The author concludes that if such investigations had been introduced, we may have avoided the thalidomide tragedy.