It is estimated that around 1.5 million women were given a controversial drug to detect early pregnancy.
Drugs containing the hormones progestogen and oestrogen were taken as a form of pregnancy test in the NHS from the late 1950s until 1970s.
Primodos was the most commonly used of these medications in the UK and was used in the NHS for the diagnosis of early pregnancy as well as for menstrual irregularities.
When used in the detection of early pregnancy, women were given two tablets to take 12 hours apart and if they did not have a bleed, the test was positive.
The Association for Children Damaged by Hormone Pregnancy Tests estimates that as many as 1.5 million women in the UK were given the test.
But studies from the late 1960s to early 1970s suggested a link between use of hormone pregnancy tests and a wide range of serious birth defects including cleft lip and palate, limb deformities and heart abnormalities.
In June 1975, the Committee on Safety of Medicines (CSM) sent an alert letter to all doctors in the UK which advised them of a possible association between hormonal pregnancy tests and an increased incidence of congenital abnormalities.
Warning notifications were put the on the product containers from 1975 onwards.
Two years later the CSM issued subsequent notifications.
Reports suggest that the hormone pregnancy test continued to be used in some parts of the health service until it was withdrawn from the market by manufacturer Schering in 1978.
That year, the Association for Children Damaged by Hormone Pregnancy Tests was formed by the mother of a child with congenital abnormalities attributed to Primodos.
In 1980, the association began legal action against Schering on behalf of two children with heart defects. But the case was discontinued two years later when a judge ruled that there was insufficient evidence linking Primodos and the conditions
Following the discovery of a cache of documents, campaigners renewed called for a public inquiry in 2014.
The Medicines and Healthcare Products Regulatory Agency (MHRA) conducted a review of the historical evidence on hormone pregnancy tests in 2014.
But it said the studies reviewed were "inconsistent in their findings for an association between use of hormone pregnancy tests and congenital anomalies and are not considered sufficient to conclude that an association exists".
Meanwhile, in 2014, the then minister for life sciences, George Freeman, confirmed that there would be an independent review of the papers and all the evidence.
In 2015, the Commission on Human Medicines convened an expert working group to review the available data on a possible association between hormone pregnancy tests and congenital anomalies.