Home pregnancy tests became widely available in 1978, although they took two hours to develop and were accurate for negative results only 80 percent of the time. Nowadays, they can supposedly tell as early as five days before a person’s missed period. Home pregnancy tests work by detecting trace levels of the pregnancy hormone human chorionic gonadotropin (hCG) in urine; hCG is present after egg implantation, which occurs six to 12 days after fertilization, and is secreted by the cells that are beginning to form the placenta.
Before the invention of this miraculous device, the most reliable test was just to wait and see. But while it might be a nice surprise to find out you’re pregnant the old-fashioned way—vomiting, missing periods, having a baby—people still wanted to know as early as possible whether they were harboring a tiny human.
So how’d they do it? Weirdly enough, it often comes back to pee.
1. The Wheat and Barley Test
One of the earliest, if not the earliest, home pregnancy tests came from ancient Egypt. In 1350 BCE, potentially pregnant people were advised to urinate on wheat and barley seeds over the course of several days; if the wheat sprouted, they were having a girl, and if the barley sprouted, a boy. If neither sprouted, they weren’t pregnant. The most interesting thing about this test was that it actually worked: In 1963, a laboratory experimented with the wheat and barley test and found that 70 percent of the time, the urine of pregnant people would cause the seeds to sprout, while the urine of non-pregnant people did not.
2. The Onion Test
While the ancient Egyptians were on to something with the wheat and barley test, they and the ancient Greeks seem to have had a fuzzy understanding of anatomy. Both Egyptian medical papyri and Hippocrates, lauded as the father of medicine, suggested that a person who suspected they might be pregnant insert an onion or other strong-smelling bulbous vegetable into their vagina overnight. If the person’s breath smelled of onions the next morning, they weren’t pregnant; this was based on the idea that if the womb was open, and wafting the oniony scent up to the mouth like a wind tunnel, there was no fetus. If the person were pregnant, then the womb would be closed, so no wind tunnel.
3. The Latch Test
From The Distaff Gospels, a collection of women’s medical lore written in the late 15th century: “My friends, if you want to know if a woman is pregnant, you must ask her to pee in a basin and then put a latch or a key in it, but it is better to use a latch—leave this latch in the basin with the urine for three or four hours. Then throw the urine away and remove the latch. If you see the impression of the latch on the basin, be sure that the woman is pregnant. If not, she is not pregnant.” Say what now?
4. Piss Prophets
As bizarre as the “latch test” sounds, it still recognized that something in a pregnant person’s pee was different than non-pregnant urine, a fact that 16th-century European “piss prophets” also recognized. These so-called experts claimed they could determine whether or not a person was with child by the color and characteristics of their urine. Some also mixed urine with wine and observed the results, a test that might have seen some success, given that alcohol can react to proteins present in a pregnant person’s pee. Of course, these piss prophets didn’t limit their divination to pregnant people; they could also, by examining urine, intuit whether the urine’s owner was suffering from any illness or disease.
5. Look for Changes in the Eye
One 16th-century physician, Jacques Guillemeau, claimed you could tell by a person’s eyes whether they were pregnant. Guillemeau, author of an influential treatise on ophthalmology, claimed that as early as the second month, “a pregnant woman gets deep-set eyes with small pupils, drooping lids and swollen little veins in the corner of the eye.” That is likely not true, but he was right about one thing: Eyes can change during pregnancy, affecting your vision. This is why it’s not a good idea to get new contacts or prescription glasses during pregnancy.
6. Chadwick’s Sign
Early on in pregnancy, at roughly six to eight weeks, the cervix, labia, and vagina can take on a dark bluish or purple-red hue, owing to the increased blood flow to the area. This remarkable indication of pregnancy was first noticed in 1836 by a French physician. It later became known as Chadwick’s sign, after James Read Chadwick, an obstetrics doctor who brought the discovery up at a meeting of the American Gynecological Society in 1886.
7. The Rabbit Test
Aside from observational tests such as Chadwick’s sign, pregnancy tests were still an unpleasant crapshoot until the 20th century. Investigation into hormones, the big thing in science at the turn of the century, just made pregnancy testing unpleasant for a bunch of rabbits, mice, and rats.
In the 1920s, two German scientists, Selmar Aschheim and Bernhard Zondek, determined that there was a specific hormone present in the urine of pregnant people that seemed to be linked to ovary growth; we now know it as human chorionic gonadotropin, or hCG. They figured this out by injecting the urine of pregnant people into sexually immature rabbits, rats, and mice, which would induce ovarian development. Most of the time, the pregnant person’s pee would produce bulging masses on the animals’ ovaries, a sure indication of the presence of hCG. So, the Rabbit Test was born.
According to a contemporary medical journal, it worked like this: A sample of urine was injected into a group of young female mice over a period of five days. On the fifth day, the mice were killed and autopsied to examine the state of their ovaries. If their reproductive bits looked excited, the test was positive. If you wanted your results in less than five days, they could simply use more mice.
This method ran through a lot of rabbits, mice, and rats; though the phrase “the rabbit died” popularly meant that the woman was pregnant, in actuality, all of the rabbits—and the mice and rats—died. Though doctors could look at the ovaries of the animal without killing it, that tended to be too much trouble.
8. The Frog Test
Though it worked on the same principle as the Rabbit Test, this one was actually a bit better—at least the animal remained alive at the end of it. By the late 1940s, scientists had determined that when a pregnant person’s pee is injected into a live toad or frog, the unfortunate amphibian will produce eggs within 24 hours. The toad or frog lived to see another day and, usually, another test.
A version of this story originally ran in 2016; it has been updated for 2023.