Hundreds of families claim that the hormone-based pregnancy test, Primodos, caused the deformities in the 1960s and 1970s, but they have never been able to establish a direct cause-and-effect link. Attempts to take the manufacturer, Schering, to court failed after legal aid was withdrawn.
The families are hoping that the discovery of thousands of papers in the Berlin National Archives may establish a link. The papers include correspondence between Dr Bill Inman, who created the UK's Yellow Card system for reporting reactions to drugs, and the manufacturer. In that, Inman said that pregnant women who took a hormone pregnancy test had "a five-to-one risk of giving birth to a child with malformations." A new warning was placed on Primodos packaging in 1975.
The papers will be reviewed by an expert panel that investigates hormone pregnancy tests.
Bayer, which took over Schering, claims that evidence that the test causes deformities is weak.