Trying to figure out if you’re pregnant is probably as old as humanity itself. People had some pretty weird methods, like urinating on wheat and barley seeds (which kind of worked!), or mixing urine with wine for divination by a “wine prophet,” or shoving an onion into a patient’s vagina to see if it gave her bad breath. (This does NOT work, Gwyneth Paltrow. Do not recommend this.)

These days, people who think they might be pregnant can pee on testing sticks that check for the hormone human chorionic gonadotropin (HCG). But nearly a century ago, when reliable HCG testing was being developed, it looked about as bizarre as the “wine prophet” and was so expensive only wealthy people could afford it.

Over-the-counter pregnancy tests cost less now but still stretch some people’s budgets — especially if they want to take them regularly. With Texas’s abortion law essentially banning abortion after six weeks of pregnancy, early detection is more important than ever.

Hormones were a relatively new concept to Western scientists in the 1920s, when gynecologists Selmar Aschheim and Bernhard Zondek were conducting research at a Berlin teaching hospital. According to a 1930 medical journal archived by the National Institutes of Health, the test they developed involved this: The urine of a possibly pregnant person was bottled and sent to a lab, where it was repeatedly injected subcutaneously into five female mice over five days. They were then killed and autopsied. If the mice had enlarged ovaries or signs of recently ovulating, then the test subject was pregnant, Aschheim and Zondek claimed.

Not long after they developed the “AZ test,” their research ended abruptly when the men, both Jewish, were forced to flee Nazi Germany. By then, American doctor Maurice Friedman had adapted the test in the United States using a rabbit. He later bragged, “The only more reliable test is to wait nine months.”

A test so involved was available only to the well-off, but soon tens of thousands of rabbits were being sacrificed in the name of science, and it quickly became a part of popular culture. Although rabbits were used for all manner of research, the “rabbit test” became synonymous with pregnancy screenings, and the phrase “the rabbit died” entered common usage as a euphemistic way of saying someone was pregnant (even though the rabbit always died during the test).

The phrase appears in a noir thriller based on the 1947 unsolved murder of Elizabeth Short (“She forced herself to look squarely at him. ‘The rabbit died.’ ”), according to a compendium of historical slang, and in a 1967 gossip column to announce comedian Joan Rivers’s pregnancy.

In her 1980 memoir about having 10 kids, humor writer Teresa Bloomingdale opened like this:

“I should have seen it coming when the rabbit died.
‘What do you mean the rabbit died?’ I asked my obstetrician in 1956. ‘Doesn’t the rabbit always die in a pregnancy test?’
‘Not this one,’ he replied. ‘I had just completed the injection when the dumb bunny jumped off the table and killed herself.’
[...] That bunny wasn’t so dumb, she was just cowardly. She foresaw my future and couldn’t bear to be involved.”

In a 1978 episode of the hit TV series “M*A*S*H,” a female character worries she’s pregnant and threatens to kill another character’s pet rabbit to find out.

Also in 1978, Billy Crystal made his big-screen debut in a movie co-written and directed by Rivers called “The Rabbit Test,” in which he portrayed “the world’s first pregnant man.” (You can find the truly ridiculous rabbit death scene on YouTube here; be forewarned the full clip contains a racial slur.)

Dead rabbits may have spread across the fruited plain, but in the United Kingdom, a slightly more humane version was developed that involved injecting a frog with a patient’s urine. If the sample contained the pregnancy hormone, the frog would lay eggs within 24 hours, providing the key information without the need to kill the animal first. Plus, the frogs could be reused.

By the 1970s, the rabbits lived. That’s when the first over-the-counter pregnancy tests became widely available. And though they no longer involved an animal, they functioned in essentially the same way, testing for HCG.

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