GLOW, a new streaming series from Netflix, is inspired by the true story of the 1980's-era Gorgeous Ladies of Wrestling show. But the wrestling isn't the only flashy element of the series that's grabbing our attention: The eighth episode features Alison Brie's character, Ruth, using a pretty unwieldy science experiment of a pregnancy test.
If you were expecting to see a simple plastic stick like the ones we use today (albeit maybe in a more '80s color palette — avocado green, perhaps?), you may be surprised to know that at-home pregnancy tests are a surprisingly recent invention. Once reserved for doctors' offices, the tests made it into drugstores in the late '70s. But that didn't necessarily mean they were user-friendly — and the early ones really did look like complicated chemistry sets.
How do home pregnancy tests even work? Well, going back to those early days, they've all been based on the detection of the hormone hCG (human chorionic gonadotropin), the American Pregnancy Association explains. After a fertilized egg implants in your uterine lining, your body starts making hCG, and levels rise rapidly, providing a good indicator that you're pregnant.
The tests done at your doctor's office will look for the presence of this hormone in your blood and can tell you exactly how much of it is in there. Pregnancy tests that are done at home, however, only look at your urine and are typically designed to just give you a simple yes or no.
The good news is, though, that urine tests — even the earliest ones — were and are over 90% accurate at detecting an increased level of this hormone. Creating a urine test required a technique that could differentiate between hCG and the other reproductive hormones your body produces naturally that are also found in urine. That breakthrough came in 1972, when a team of researchers at the National Institutes of Health found a type of analysis that distinguishes between hCG and luteinizing hormone. However, the test was still reserved for doctors. People who wanted to get their urine tested still had to take it in — and wait a week or two to get their results, Smithsonian reports.
So the introduction of the first varieties of at-home tests in the late '70s was very much welcome, but they weren't exactly simple to use. They involved mixing compounds together (including sheep's blood): "It’s like you’re in a laboratory. It’s like you’re a mad scientist," Brie told Vulture of the filming experience. "You have to pour a little bit into one thing, then you pour another chemical into another thing. Then you mix them together. Then you wait." In fact, the first tests took up to two hours to give you results.
Luckily, later versions (including the one shown in GLOW) didn't take quite as long, getting the process down to about 20-30 minutes. Still, that sounds like a lot if you're used to today's two-to-three minute version (which is already pretty nerve-racking).
Innovations continued throughout the '80s and '90s, bringing us to the the one-step pee-on-a-stick variation we know today, io9 explains. The 1990s also saw the introduction of enzyme-based testing (ELISA), which allowed the tests to work even faster and provide clearer results. These days, we also have the option to use digital screens and even one enabled with Bluetooth.
Of course, even if they're easier to use, pregnancy tests are still definitely stressful. So, if there's any ambiguity about your at-home test (e.g. different tests have given different results), it's a good idea to check in with your doctor — and be glad you don't have to fiddle with any test tubes yourself.