New evidence has emerged linking Primodos, a 1960’s pregnancy test drug, to serious birth defects, as well as a major scandal and cover-up that hid that information from the public.

The Sky News documentary Primodos: The Secret Drug Scandal details the groundbreaking and heartbreaking findings that Schering, the German drug company that made Primodos, conducted studies and learned of its potential to cause birth defects, but kept the drug in circulation well into the 1970s.

Millions of women around the world–from the United Kingdom to the United States (under name Gestest) to Australia–were prescribed the hormone-based medication by their doctors to detect pregnancy as early as 1958.

Primodos consisted of two pills that contained high levels of synthetic progesterone, which was supposed to induce a period if the woman wasn’t pregnant. Women were advised to take the first pill and, if they didn’t menstruate, take the second one the next day.

If a woman was actually pregnant, Primodos is alleged to have caused a disruption to that stage of embryonic development, disrupting for example, the growth of limbs, facial features, and spinal development.

The drug was never clinically tested and not determined to be safe during pregnancy. The components of Primodos were later found to be 13 times stronger than the morning after pill.

In 1978, Primodos was discontinued after doctors noticed an increase in the number of deformed babies born to mothers who had been prescribed the drug.

Primodos, which was manufactured by the drug company Schering, now Bayer, continues to deny it caused deformities in children.

Watch the documentary below: