A Short History of Pregnancy Tests
Believe it or not, pregnancy tests have been around for thousands (yes, thousands) of years. Certainly not in the form we have known them but there have been methods used for centuries to determine whether a woman was pregnant.
Way Back in 1350BCE ...
One of the earliest pregnancy tests recorded comes from Egypt, around 1350BCE. An ancient Egyptian papyrus described a test in which a woman who might be pregnant could urinate on wheat and barley seeds over the course of several days. "If the barley grows, it means a male child. If the wheat grows, it means a female child. If both do not grow, she will not bear at all." This theory was actually tested in 1963 and found to be 70 percent accurate. The urine of a pregnant woman did cause growth and the urine of non-pregnant women and men did not. It appears this was one of the very first tests used to distinguish a unique component in the urine of women who were pregnant. The speculation of those testing the theory was that the elevation of estrogen found in the urine of pregnant women may have been what caused the grain to grow.
Just Mix It with a Little Wine
The Middle Ages saw the use of visual aspects of urine as a method to determine pregnancy. "Piss-prophets" in Europe claimed to be able to determine pregnancy (as well as diagnose disease) by examining the color of urine. In a text written in 1552, a description of pregnancy urine read, "clear pale lemon color leaning toward off-white, having a cloud on its surface." Wine was mixed with urine in other tests and the results observed. It turns out that alcohol does react with certain proteins that are present in urine, so there may have been some credibility to those tests.
The Discovery of Hormones
At the end of the 19th Century, physicians started suggesting that certain organs secreted chemicals into the body and that understanding what they were and how they interacted was crucial to understanding human biology. In the 1890s, Ernest Starling gave these chemical messengers a name - he called them "hormones." It was also in this time period that a movement for public health was growing and women were advised to see their doctors as soon as they could when they suspected they were pregnant. Prenatal care was founded on the concept of improving the health of mothers and their babies - although most women didn't seek the help of a doctor or midwife until their pregnancy was almost over.
The 20th Century and Revolutionary Changes
It was the 20th Century that brought about the most major changes in determining pregnancy as research on human reproduction took giant leaps forward. The progress in indentifying the hormone only found in pregnant women (hCG) lead to the development in the late 1920s of a pregnancy test that identified the presence of human chorionic gonadotropin (hCG) in urine. The test consisted of injecting the urine of a pregnant woman into an immature rat or mouse. If the urine did not have hCG in it, then there would be no reaction in the animal. If it did, the rat would go into heat in spite of the fact it was technically too immature to do so. The test showed that during pregnancy there was an increase in hCG in the woman's body.
By the 1930s hormone research was well under way and rabbits, frogs, toads and rats were used to be the recipients of the hormone rich urine. It was a costly, long process that meant the sacrifice of many animals - but it started research moving forward. By the 1960s testing was more advanced but still insensitive in many respects to the difference between hCG and LH (luteinizing hormone), which meant that pregnancy tests were not that reliable.
In the 1970s there were two major shifts that occurred during the time of the sexual revolution: increased research in reproductive health and the desire for women to be able to determine if they were pregnant as early as possible. This is when prenatal care and prenatal testing become mainstream in the US. The first self-tests were called tube agglutination tests and required prepackaged red blood cells to detect hCG in urine. If the test was positive, a ring would show up at the bottom of the tube. It required a miniature lab setup and was quite the process. This home test took two hours to complete.
Today's Pregnancy Tests, From Days to Minutes
Today, we have tests that are easy to perform and accurate to 97%, or in the case of blood tests, 100%. It is possible to have a pregnancy test done using either blood or urine. However, the blood tests have to be done by a doctor while the urine tests can be done at home by a woman herself. No more mixing - just a little urine on the test strip and the results appear in minutes. One pregnancy test, First Response Early Response test (FRER) says you can use it three to four days before your expected period date. You've come a long way, Baby.
To learn more about pregnancy tests, today's version, check out our article here.