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Controversial pregnancy tests used in the 1960s COULD have caused severe birth defects, new evidence suggests

Mirror logo Mirror 14/2/2018 Shivali Best

Controversial test drugs used in the 1960s and 1970s had the potential to cause deformities in embryos, a new study suggests.

The hormone pregnancy tests (HPTs) were given to an estimated 1.5 million women to determine whether or not they were expecting.

But in 1978, the tests were withdrawn from the market after studies suggested there was a link between the tests and a wide range of serious birth defects.

A recent review into the tests concluded the scientific evidence "does not support a causal association" between the use of HPTs, such as Primodos, and birth defects or miscarriage.

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But campaigners called the review by the Commission on Human Medicines a "whitewash", saying the expert working group did not examine all of the available evidence on the use of the drugs.

Now the latest study, published in the journal Scientific Reports, found that components of the controversial drug caused deformations to fish embryos just hours after they received a dose.

Norethisterone acetate and Ethinyl estradiol, components of the drug, are still used in other medications including treatments for endometriosis and contraceptives.

The study, led by Dr Neil Vargesson from the University of Aberdeen, found these drugs can cause developmental anomalies when directly applied to zebrafish embryos.

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Science Photo Library RM

Damage was "extremely rapid", within one hour zebrafish embryos showed significantly reduced movement, and, within four hours, "obvious morphological defects”.

The authors wrote: "Norethisterone acetate and Ethinyl estradiol cause embryonic damage in a dose and time responsive manner. The damage occurs rapidly after drug exposure, affecting multiple organ systems.”

They also found drug components accumulate in the forming zebrafish embryo for at least 24 hours.

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Dr Vargesson said: "At the moment the scientific research into whether or not Primodos caused these birth defects is inconclusive.

"What this study highlights is that there is a lot still to be learned about Primodos and more widely its components effects on mammals.

"Our experiments with the zebrafish embryos shows quite clearly the effects the Primodos components have.

"This does not mean it would do the same in humans of course, we are a long way from saying that but we need to carry out more research into these components because they are still in drugs today and in some cases in much higher doses than those found in Primodos.

"The assumption by some previously has been that the doses given to mothers was too low to cause any damage but our study shows that the levels of Primodos' components accumulate in the embryos over time because they don't have a fully functional liver that can break down the drug.

"This, too, is new information and if the same thing happens in mammals, these drugs could build up in the embryo to much higher levels than shown in the mother's blood.”

Dr June Raine, director of vigilance and risk management of medicines at the Medicines and Healthcare products Regulatory Agency, said: "Patient safety is our highest priority and the safety and effectiveness of all available medicines is kept under constant review. As new data comes to light, action is taken as appropriate to make sure the benefits of medications outweigh the risks.”

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