Experts are to examine new evidence about a pregnancy-testing drug, which parents claim caused their children serious birth defects. 

Hundreds of families have been campaigning for years for compensation alleging Primodos, a hormone-based drug manufactured by Schering and available during the 1960s and 1970s, led to their children being born with serious abnormalities – including missing limbs, heart defects and spina bifida. 

The drug was discontinued in 1978 and Bayer, which now owns Schering, has denied the allegations. 

Now, thousands of pages of documents have been discovered in the Berlin National Archives. According to Sky News, which has investigated the files, they show that in January 1975, the principal medical officer for the British government, Dr William Inman, had found women who took a hormone pregnancy test “had a five-to-one risk of giving birth to a child with malformations”. 

The evidence reportedly shows Inman, who died in 2005, wrote to manufacturer Schering so it could “take measures to avoid medico-legal problems”. Later documents allegedly claim he destroyed the materials that his findings were based on to “prevent individual claims being based on his material”. 

Primodos detected pregnancy by prompting menstruation in women who were not pregnant using two hormone-based tablets.

Attempts by alleged victims to bring their case before UK courts collapsed in 1982 and legal aid was withdrawn from the 700 families then suing Schering for compensation. At the time it was considered unlikely they would be able to prove a causal link between the use of hormonal pregnancy tests and the children’s defects. But these new documents have given families fresh hope. They will be examined by the Commission on Human Medicines’ Expert Working Group on Hormone Pregnancy Tests. 

Bayer rejects any suggestion anything has been concealed by Schering and insists sales of Primodos were in compliance with prevailing laws. 

Linda Millband, national practice lead of Thompsons Solicitors’ clinical negligence team, said: “We welcome the news of this new evidence and it is important that it will be rigorously analysed. 

“At Thompsons, we have experience of working with families and individuals across the country who have been victim of medical negligence through defective medical products, and will be monitoring the findings of the Commission’s examination closely.”