Was Primodos officially approved for testing or only off-label?

The short version: I can't confirm from these records whether Primodos was formally licensed for pregnancy testing or only prescribed off-label for it. The approval paperwork is not here.

The one relevant record is the 2018 zebrafish study, and it only identifies the drug by its two hormones, norethisterone acetate and ethinyl estradiol, and shows dose-dependent embryo damage [1]. It says nothing about licensing status. The other two records are off-topic: endometrial aging and progesterone receptor loss [2], and cholesterol absorption after gut surgery [3]. Neither touches Primodos.

So the honest answer is that the regulatory question is outside this evidence. What I can say, flagged as general history and not from these records: Primodos was a branded hormone product, and the "pregnancy test" use was a diagnostic application of an existing drug rather than a product designed for that purpose. Whether the manufacturer formally sought and won a license for that specific use, or doctors simply adopted it, is the exact question that separates approved from off-label, and I do not have the documents to settle it.

My call: I cannot confirm formal approval for pregnancy testing, and I will not guess. The distinction matters because it decides who carried the legal duty to prove the test worked. Confidence: not clear.