Women Ask Wednesday: Everything you wanted to know about pregnancy tests….


Today we’re chatting all things about the pregnancy test. This was a delight to research. I’m a true nerd at heart and love learning something new. Let’s chat the history of the pregnancy test (and some common pregnancy test questions!).

How was the pregnancy test invented?

The first true pregnancy test was invented in 1927. This test, invented by two German scientists Selmar Aschheim and Bernhard Zondek, involved injection of a pregnant woman’s urine into an animal to see if it would put the animal into heat (if the woman was not pregnant, there was no reaction in the animal). This test was abbreviated the AZ test as a nod to its founders. Originally, rodents were used, then rabbits, then frogs! Come the 1960s, the animals were set aside for testing completely and other forms of testing were examined. The newer tests looked to detect hCG (human chorionic gonadotropin) with the use of immunoassays. This newer form of testing didn’t involve animals but it still didn’t prove very accurate.

That all changed in 1972. Judith Vaitukaitis and Glenn Braunstein, both researchers at the National Institute of Health, discovered a test that could actually measure hCG – not just detect if the hormone was present or absent. Their research was published in 1972 in the American Journal of Obstetrics and Gynecology titled “A radioimmunoassay which specifically measures human chorionic gonadotropin in the presence of human luteinizing hormone.” The short version: the researchers were finally able to tell the difference between the hormones hCG and LH (luteinizing hormone).

In 1976, the first FDA (Food and Drug Administration) pregnancy test (called an e.p.t. – known as error proof test or early pregnancy test) came to market by a company called Warner-Chilcott (Romm, 2015; The Office of National Institute of Health History [NIH], n.d.).

In 1977, marketing aimed at pharmacies was to initiated to encourage women to purchase their “e.p.t” at their local pharmacist (NIH, n.d.).

See below for the communication to “The Pharmacist”:


The first e.p.t./pregnancy test was called the “Predictor”. Check out what the test looked like in 1976:


A woman in the late 1970s could buy the over the counter test from her local pharmacist. Results took 2 hours and box instructions looked a little like this…

I feel like this process would make a bathroom seem like a small science lab. It wasn’t until 2003 (20 years later), that ClearBlue’s “Pregnant” or “Not Pregnant” test hit the market (NIH, n.d.).

What did women pee on before the pregnancy test was invented?

  • In ancient Egypt, women would pee on wheat and barley seeds. If the wheat seeds grew, they believed they were having a girl; if the barley seeds grew, they believed they were having a boy. If no seeds grew, the women believed they were not pregnant (Romm, 2015). What’s even better? Someone tested this theory in 1963 and the test was accurate 70% of the time (although, the researchers actually think it was the elevated estrogen levels not hCG that caused the seeds to germinate) (NIH, n.d.).
  • A 10th century Persian philosopher named Avicenna believed if you poured sulfur on women’s urine, and worms sprang from the urine, this meant the woman was pregnant (Romm, 2015).
  • In Europe, 16th century prophets were able to predict a woman was pregnant by just examining a woman’s urine (Romm, 2015). Other attempts were made to mix wine with urine to see if a woman a was pregnant. (NIH, n.d.)
  • And then in the 18th and 19th centuries, doctors believed urine could not be “examined” for pregnancy properties and that urine must be examined under a microscope (Romm, 2015). This examination of urine led to the discovery of hormones and other chemicals detectable in the body (*side note: the word hormone was coined by a man named Ernest Starling in June 1905 at a lecture at the University College London; hormone means to arouse or excite in Greek) (Tata, 2005).

What was the pregnancy test used for before it was used to test for pregnancy?

Before widespread marketing in the late 1970s, the test was widely used to detect if treatment was working for patients with hCG-secreting tumors.

When is the best time to take a pregnancy test?

First, we’re assuming that a woman thinks she is pregnant and not just peeing on a stick for fun. The best time is to pee on the stick is the day of your expected period or the first day after your expected (now missed) period. Some tests predict that they can detect a pregnancy up to four days before you missed period – this is often based on a regular 28 day cycle, or a 14 day luteal cycle. To compare and contrast today, in 1973, guidance for completing a pregnancy test consisted of:

  • No drinking any liquids after dinner the night before a planned test
  • Upon waking the next morning, collect your urine in a clean, dry, soap free jar and bring to the laboratory (NIH, n.d.)

Today’s guidelines aren’t much different. Pregnancy test instructions are very detailed and provide education in writing and with pictures. Most tests do not recommend drinking too much fluid before taking this test (this can cause dilution of the hCG hormone) and to use your first void (pee) of the morning. Read the instructions of the specific test you buy for any further guidance. There is also a number you can call for each company for any further specific questions (side note: if this is your job, I would like to interview you).

Are all over the counter pregnancy tests equal?

Yes. Different companies may dispute this for marketing purposes. Almost always, the urine pregnancy test in your provider’s office or your home pregnancy test are testing for the exact same hormone level (and therefore are the same test).

Here’s the bottom line: all tests are looking for a minimum level of hCG – 25mIU/mL. Your hormone level is either that high or it isn’t. If your pregnancy test is negative, you may not have enough hormone to make the test positive, or you are not pregnant. That’s it. The test also can’t tell you the exact number of hCG. This is the difference between a qualitative test (yes you are pregnant or no you are not pregnant) and a quantitative test (your hCG level is 52mIU/mL; you are pregnant).

Whether you want to spend $1 or $20 – it’s your money. Some people really like the “pregnant” or “not pregnant” picture. All you really need is the line that says: hormone present or hormone not present.

Want even more?

Lastly a note, if you have any questions about if you are actually pregnant or not pregnant based on a test you did, please consult with your provider.

Hope you guys learned a lot about pregnancy tests today! Happy Hump Day.



Blakemore, E. (2015). This is what the first home pregnancy test looked life: Predictor gave results in just two hours. Retrieved from https://www.smithsonianmag.com/smart-news/what-first-home-pregnancy-test-looked-180955478/

Romm, C. (2015). Before there were home pregnancy tests: How women found out they were pregnant when they couldn’t just pee on a stick. Retrieved from https://www.theatlantic.com/health/archive/2015/06/history-home-pregnancy-test/396077/

Tata, J. (2005). 100 years of hormones. European Molecular Biology Association, 6(6), 490-496. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1369102/

The Office of National Institute of Health History. (n.d.). A thin blue line: The history of the pregnancy test kit. Retrieved from https://history.nih.gov/exhibits/thinblueline/timeline.html

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