A similar method, that is detecting hCG in urine, was used in the early 20th century by injecting into xenopus frog. https://www.ncbi.nlm.nih.gov/pmc/articles/

A similar method, that is detecting hCG in urine, was used in the early 20th century by injecting into xenopus frog. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2211252/pdf/brmedj04228-0010.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2211252/pdf/brm... Another recent article: https://www.smithsonianmag.com/smart-news/doctors-used-to-use-live-african-frogs-as-pregnancy-tests-64279275/ https://www.smithsonianmag.com/smart-news/doctors-used-to-us...