Aberdeen University lecturer Neil Vargesson published a study earlier this year bringing government findings into the spotlight.
Last year the hormonal pregnancy test Primodos was declared safe by the Commission of Human Medicines, causing a stir amongst the thousands who believe the drug to have caused birth defects.
The rationale behind this pregnancy test, which was taken off the UK market in 1978, was that if a menstrual bleed was not caused by one pill, a second pill was to be taken. Absence of a menstrual bleed after the second pill would indicate pregnancy.
The pill itself contained doses of chemicals now used in contraceptives at an incredibly high concentration.
Norethisterone acetate and Ethinyl estradiol are compounds used in Primodos which are now used as contraceptives and to treat endometriosis.
Within 10 years of its release, a study had been published connecting Primodos to birth defects. However, on the 22nd of November 2017, nearly 40 years later, a study by the Commission on Human Medicines (CHM), part of the UK’s Department of Health, reported no causal link between Primodos and birth defects.
In his study, published in Nature, Dr Vargesson found that compounds used in Primodos caused defects in developing zebrafish in a time and dose dependent manner. Nerve outgrowth and blood vessel patterning were affected in embryos for up to 24 hours.
When asked about the government findings, Dr Vargesson stated:
“Nobody can say, hand on heart, that Primodos is definitely safe or unsafe. Surely the CHM are responsible for ensuring public safety, and using data from 30-40 years ago is illogical and unscientific. Progesterone, which Primodos is based on, is within the mother all the way through pregnancy – which could mean Primodos is safe. But there is no modern evidence.”
Since the publishing of this study, Theresa May has issued an inquiry into Primodos and two other potential hazards to birth.
From an embryological perspective, the results in zebrafish must be replicated in animal models more similar to humans before any conclusion is made.
The next step of the process is to assess the impacts of Primodos on mammal models. Only then can we confirm whether or not Primodos can be considered dangerous to developing embryos and ensure that those involved get closure.
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