Before at-home pregnancy tests, doctors relied on a large, aquatic frog. And the results were accurate.

While peeing on a plastic stick might not seem like the most sophisticated means of determining whether or not you’re carrying human life, it’s worthwhile remembering that just a handful of decades ago doctors relied on a frog.

Yes, as recently as the 1960s, there were labs scattered around the world dedicated to a single species, known as the African clawed frog. Specimens were shipped from country to country, and bred in their tens of thousands. All because this unassuming little amphibian served an unlikely function as the medical-standard human pregnancy test.

The bizarre discovery was made in the ’30s by a British zoologist named Lancelot Hogben (it’s true, promise). While studying hormones, Hogben conducted an experiment that involved injecting extracts from an ox’s pituitary gland into an African clawed frog. The surprise result? The frog laid eggs.

By then, scientists were aware that a pregnant woman’s urine contained hormones made in the pituitary gland, and a curious Hogben and his colleagues simply put two and two together.

What became known as the Hogben test was a simple as it was odd. As The Smithsonian Museum explains: “Doctors would ship urine samples to frog labs, where technicians would inject female frogs with a bit of the urine into their hind leg. The animals would be placed back into their tanks, and in the morning the technicians would check for tell-tale frog eggs dotting the water. If the female frog had ovulated, that meant the woman who provided the urine was pregnant and the pregnancy hormone, human chorionic gonadotropin, had kicked off ovulation in the frog”.

It was accurate, too. Researcher Dr Edward Elkin wrote in The British Medical Journal in 1938, “Among the 295 tests which I have done so far and in which 2,112 frogs were used, I have not seen one clear positive that did not indicate a pregnancy”.

The Hello Bump team answer your pregnancy questions.

Throughout the 1930s, 40s, 50s, this was the primary pregnancy test available to women. Prior to that, it involved injecting their urine into mice or rabbits, which were then dissected to see if the animal’s ovaries had enlarged.

The Hogben test was far more efficient, less costly and at least a little more humane – an African clawed frog could live up to 30 years in captivity.

However, by the 1960s scientists began to investigate ways to isolate the key hormone the frogs were reacting to – human chorionic gonadotropin (hCG) – and develop immunological tests. The following decade, the first at-home tests hit the market. One of the first was designed by Margaret Crane, a freelance graphic designer at a pharmaceutical company.

Though it looked more like a high-school chemistry set – complete with a dropper  –  it was considered an integral part of women’s fight for agency in their own health care.

“I was absolutely certain that [a home pregnancy test] would be very useful,” she told Bonhams. “A woman should have the right to be the first to know if she was pregnant, and not have to wait weeks for an answer.”

(Sadly, Crane assigned the patent for her design to her parent company, and was never compensated or formally credited.)

As these tests improved, the once-essential African clawed frog was gradually retired from its role as living pregnancy test. Still, the species hasn't been completely abandoned by the scientific community. Much to the disappointment of animal rights activists, it continues to be favoured for experimentation and is a staple of research laboratories around the world. A number were even sent into space aboard the Space Shuttle Endeavour in 1992, so that scientists could test the impact of zero gravity on reproduction and development.

Four decades on, we have that large, aquatic frog and a handful of bright minds to thank for today's slimline testing sticks, with their digital screens and conception calculators. Thank goodness we never have to go back.

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