The Primodos Scandal - Part 1

What the Evidence Says

In 1956, Oral hormones, such as Primodos, were used as pregnancy tests (HPTs). They contained ethinylestradiol and norethisterone, the latter in much larger amounts than those included in current combined oral contraceptives. They were supposed to work by inducing bleeding similar to menstruation in those who were not pregnant.

Schering, the manufacturer, removed the indication for Primodos as a pregnancy test in 1970. However, doctors were not informed, and consequently, prescribing remained mostly unchanged: as a consequence, more than a million women took HPTs in the UK.

In 1975 the Committee on Safety of Medicines concluded that a warning should be added to the Data Sheets, stating that HPTs should not be taken during pregnancy.  Two years later, regulators wrote to doctors stating, "The association is confirmed."