Hormone pregnancy tests

Hormone pregnancy tests, such as Primodos, were widely used in the UK from the late 1950s until the 1970s. These pregnancy tests involved taking tablets containing synthetic hormones to see if they would induce bleeding (like a period). If no bleeding occurred, the test was positive.

From the late 1950s onwards, clinicians and researchers raised concerns about a potential link between mothers’ use of hormone pregnancy tests and children being born with congenital abnormalities. Although the evidence was not considered conclusive, the Committee on Safety of Medicines (which advised the UK medicines licencing authority at the time) issued alerts in 1975 and 1977 advising that hormone pregnancy tests should no longer be used. However, hormone pregnancy tests continued to be used in the UK after this date.

The Association for Children Damaged by Hormone Pregnancy Tests, a campaigning charity, formed in 1978 to campaign for recognition and redress for harms caused by hormone pregnancy tests.

Reviews of evidence for hormone pregnancy tests

Several bodies have reviewed the evidence of the link between the use of hormone pregnancy tests and congenital abnormalities. They have reached different conclusions.

The UK Government has repeatedly endorsed the findings of the Commission on Human Medicines Expert Working Group review conducted in 2017. This review concluded that the available scientific evidence cannot causally link the use of hormone pregnancy tests and the development of congenital abnormalities, miscarriage or stillbirths.

The Independent Medicines and Medical Devices Safety review

In July 2020, the report of the Independent Medicines and Medical Devices Safety Review, First Do No Harm, concluded that hormone pregnancy tests should not have been available from 1967 onwards. The review found that regulatory action on hormone pregnancy tests was inadequate and that medicines regulators had failed to prevent the continued use of tests after safety concerns were raised.

Although determining whether hormone pregnancy tests caused harm was outside the review’s scope, the report also noted that “a possible association between [hormone pregnancy tests] and malformations exists and cannot be precluded”. It said those affected should be entitled to support.

The government did not accept the review’s recommendations about the creation of specialist support centres for those affected by medicines used in pregnancy (including hormone pregnancy tests) or the creation of a redress scheme for those affected by hormone pregnancy tests.

Legal cases

In 1977, the Association for Children Damaged by Hormone Pregnancy Tests initiated legal proceedings against the manufacturer of the hormone pregnancy test Primodos on behalf of two children with heart defects. The claims were discontinued in July 1982 after the judge found there was insufficient evidence linking Primodos to the conditions.

In 2019, new legal proceedings were initiated against three pharmaceutical companies who manufactured hormone pregnancy tests and the Secretary of State for Health and Social Care, who is responsible for the regulation of the supply and use of medicines. In May 2023, these new claims were dismissed (struck out) as an “abuse of process”. The judge concluded that no new evidence to establish causation was available, and that there was “no viable plan to progress these claims and no real prospect of success”.