"The process by which the pill came to be marketed in Britain and the United States differed, according to the distinct drug regulatory mechanisms of each country. The United States had some premarketing control over the introduction of new drugs onto the marketplace, which had been established in 1938, but Britain had no premarketing controls aside from a requirement that all pharmaceutical manufacturers be licensed. In the end, however, both countries had similar versions of the pill on the market within months of each other."