1 00:00:01,920 --> 00:00:04,280 Speaker 1: Welcome to brain Stuff, a production of I Heart Radio. 2 00:00:06,600 --> 00:00:10,680 Speaker 1: Hey brain Stuff, Lauren Volga Baum Here. When they're in 3 00:00:10,840 --> 00:00:15,000 Speaker 1: our human world, rabbits can be interesting pets, a source 4 00:00:15,040 --> 00:00:19,480 Speaker 1: of food assistance in classic magicians, stage shows, or animal models, 5 00:00:19,480 --> 00:00:22,759 Speaker 1: and laboratory tests. Of course, we hope that in all 6 00:00:22,760 --> 00:00:25,680 Speaker 1: of these cases, the rabbits in question are being treated 7 00:00:25,720 --> 00:00:28,880 Speaker 1: by the humans in question with the utmost care. But 8 00:00:29,160 --> 00:00:31,720 Speaker 1: did you know that from the nineteen thirties to the 9 00:00:31,720 --> 00:00:36,720 Speaker 1: early nineteen sixties, lab rabbits were key element in human 10 00:00:36,800 --> 00:00:41,519 Speaker 1: pregnancy tests. It's true, and it's even weirder than it sounds, 11 00:00:41,720 --> 00:00:45,479 Speaker 1: because it involved injecting those rabbits with human urine. But 12 00:00:45,880 --> 00:00:49,160 Speaker 1: let's back up a little here. The basic principles behind 13 00:00:49,280 --> 00:00:53,000 Speaker 1: testing urine for pregnancy date back thousands of years and 14 00:00:53,080 --> 00:00:57,880 Speaker 1: continue to this day. Historians believe the physicians of ancient 15 00:00:57,920 --> 00:01:01,000 Speaker 1: Egypt were the first to discover a method detecting pregnancy 16 00:01:01,120 --> 00:01:03,720 Speaker 1: through the study of urine. We've talked about this one 17 00:01:03,720 --> 00:01:08,160 Speaker 1: on the show before. By BC or so, ancient Egyptian 18 00:01:08,200 --> 00:01:11,080 Speaker 1: women could determine whether they were pregnant by urinating in 19 00:01:11,160 --> 00:01:14,760 Speaker 1: two different bags, one filled with barley and the other 20 00:01:14,880 --> 00:01:18,360 Speaker 1: with wheat. If the grain and either bags sprouted, it 21 00:01:18,520 --> 00:01:22,080 Speaker 1: meant she was expecting fast forward all the way. In 22 00:01:22,120 --> 00:01:24,600 Speaker 1: the nineteen sixties, a study found that this is actually 23 00:01:24,640 --> 00:01:28,040 Speaker 1: accurate about seventy percent of the time because the elevated 24 00:01:28,160 --> 00:01:31,560 Speaker 1: estrogen levels and a pregnant person's urine can promote seed growth. 25 00:01:32,600 --> 00:01:35,199 Speaker 1: What wasn't accurate was the attempt to determine the sex 26 00:01:35,240 --> 00:01:38,120 Speaker 1: of the child based on which sprouted first, Barley for boys, 27 00:01:38,120 --> 00:01:43,160 Speaker 1: wheat for girls. But still not bad and historians think 28 00:01:43,280 --> 00:01:47,400 Speaker 1: this marked the beginning of medical urine examination and potentially 29 00:01:47,480 --> 00:01:51,680 Speaker 1: laboratory medicine itself. More than three thousand years of urine 30 00:01:51,720 --> 00:01:55,720 Speaker 1: examination also called eurro scopy or your analysis have followed, 31 00:01:56,280 --> 00:01:59,400 Speaker 1: with varying accuracy. There was a bit of an expose 32 00:01:59,520 --> 00:02:02,320 Speaker 1: in the sixty hundreds in London that called out fraudulent 33 00:02:02,360 --> 00:02:07,160 Speaker 1: physicians using urine to diagnose pregnancy and lots of other conditions. 34 00:02:07,520 --> 00:02:12,080 Speaker 1: The whistleblower referred to these frauds as piss profits. But 35 00:02:12,639 --> 00:02:17,560 Speaker 1: urine research continued, and meanwhile, in the late eighteen nineties, 36 00:02:17,800 --> 00:02:22,280 Speaker 1: scientists discovered the existence of hormones. A hormone is a 37 00:02:22,320 --> 00:02:26,399 Speaker 1: product that sells make to regulate specific cellular activities such 38 00:02:26,400 --> 00:02:30,079 Speaker 1: as cell growth and division, and in the nineteen twenties, 39 00:02:30,360 --> 00:02:35,000 Speaker 1: scientists pinpointed a specific hormone called human choreonic ganado trop in. 40 00:02:35,639 --> 00:02:39,639 Speaker 1: It's also called hCG because that's much easier to say. 41 00:02:39,960 --> 00:02:43,120 Speaker 1: This hormone is found almost exclusively in the blood and 42 00:02:43,280 --> 00:02:46,280 Speaker 1: urine of pregnant people, though we now know that certain 43 00:02:46,320 --> 00:02:51,440 Speaker 1: cancers also produce it in anyone. But intrigued by this 44 00:02:51,520 --> 00:02:55,079 Speaker 1: hormones linked to pregnancy, a couple of German researchers set 45 00:02:55,080 --> 00:02:58,560 Speaker 1: out to develop a method of testing for hCG in urine. 46 00:02:59,440 --> 00:03:02,200 Speaker 1: They decide to exploit the fact that hormones from one 47 00:03:02,240 --> 00:03:06,440 Speaker 1: animal can generate biological responses in the bodies of other species, 48 00:03:06,880 --> 00:03:10,880 Speaker 1: sort of like those sprouting seeds. They discovered that by 49 00:03:10,960 --> 00:03:14,760 Speaker 1: injecting female mice with a pregnant woman's urine, they could 50 00:03:14,800 --> 00:03:18,000 Speaker 1: stimulate the mice's ovaries and cause them to go into 51 00:03:18,040 --> 00:03:21,520 Speaker 1: heat within a few days. They called this test the 52 00:03:21,600 --> 00:03:25,240 Speaker 1: A Z test. Will note here that just as analyzing 53 00:03:25,400 --> 00:03:28,160 Speaker 1: urine has a long history and medical science, so too 54 00:03:28,200 --> 00:03:32,480 Speaker 1: has the use of animals. While often controversial and hopefully 55 00:03:32,520 --> 00:03:36,040 Speaker 1: replaceable by technology in the future. A number of experiments 56 00:03:36,040 --> 00:03:39,880 Speaker 1: on animals called bioassays, have led to important breakthroughs in 57 00:03:39,880 --> 00:03:45,600 Speaker 1: medical science anyway, during the nineteen thirties, researchers applied the 58 00:03:45,640 --> 00:03:50,120 Speaker 1: Azy tests methodology to two other species. In South Africa, 59 00:03:50,240 --> 00:03:54,280 Speaker 1: researchers adapted it for use in frogs, inventing the hogbin test. 60 00:03:54,840 --> 00:03:57,400 Speaker 1: The frogs would lay eggs if the urine they were 61 00:03:57,440 --> 00:04:01,880 Speaker 1: injected with contained hCG. This test was used tens of 62 00:04:01,920 --> 00:04:05,080 Speaker 1: thousands of times in the nineteen forties through the nineteen sixties, 63 00:04:06,240 --> 00:04:09,680 Speaker 1: and at the University of Pennsylvania Medical School, one Dr 64 00:04:09,800 --> 00:04:14,360 Speaker 1: Maurice Friedman made a breakthrough with rabbits similar to mice, 65 00:04:14,600 --> 00:04:18,239 Speaker 1: If hCG is present in urine injected into female rabbits, 66 00:04:18,600 --> 00:04:21,640 Speaker 1: the urine stimulates changes to the rabbit's ovaries within just 67 00:04:21,680 --> 00:04:25,640 Speaker 1: a few days. The hCG basically fools the rabbit's body 68 00:04:25,760 --> 00:04:29,720 Speaker 1: into temporarily thinking it's pregnant, and the rabbit's ovaries produced 69 00:04:29,720 --> 00:04:33,680 Speaker 1: temporary tissue structures that a researcher can spot. The urine 70 00:04:33,680 --> 00:04:37,640 Speaker 1: injection itself didn't harm the rabbit or the mice or frogs, 71 00:04:37,680 --> 00:04:40,960 Speaker 1: but unfortunately, the fastest way to check the ovaries of 72 00:04:41,000 --> 00:04:45,440 Speaker 1: the mammals was to euthanize and dissect the animal. Thousands 73 00:04:45,480 --> 00:04:48,600 Speaker 1: of rabbits were sacrificed every year, to the point that 74 00:04:48,760 --> 00:04:51,720 Speaker 1: the rabbit died became a euphemism for saying that someone 75 00:04:51,800 --> 00:04:57,279 Speaker 1: was pregnant. The frogs, however, were unharmed and uh reusable. 76 00:04:57,960 --> 00:05:01,440 Speaker 1: Luckily for the bunnies, though, The first immuno essay that 77 00:05:01,520 --> 00:05:04,719 Speaker 1: could test directly for hCG and a sample of urine 78 00:05:04,960 --> 00:05:09,120 Speaker 1: was developed in nineteen sixty. Immuno essays are tests that 79 00:05:09,279 --> 00:05:14,080 Speaker 1: use specific molecules called antibodies that can bind onto whatever 80 00:05:14,160 --> 00:05:17,640 Speaker 1: type of particle you're looking for in some detectable way. 81 00:05:17,880 --> 00:05:20,880 Speaker 1: Maybe it makes the sample clump up, or maybe the 82 00:05:20,920 --> 00:05:23,719 Speaker 1: antibody is attached to an enzyme that will change the 83 00:05:23,760 --> 00:05:28,040 Speaker 1: color of a test strip from white to blue. And yes, 84 00:05:28,160 --> 00:05:33,039 Speaker 1: today's at home COVID tests are also immuno essays. But 85 00:05:33,279 --> 00:05:36,479 Speaker 1: it took over a decade to turn this initial discovery 86 00:05:36,600 --> 00:05:40,720 Speaker 1: into something really usable for pregnancy testing. It involved a 87 00:05:40,760 --> 00:05:44,800 Speaker 1: lot of research and societal changes, including advancements in prenatal 88 00:05:44,880 --> 00:05:47,880 Speaker 1: care and the legalization of most abortions at a national 89 00:05:47,960 --> 00:05:50,520 Speaker 1: level via the Supreme Court's decision in Roe v. Wade 90 00:05:50,520 --> 00:05:54,400 Speaker 1: in ninety three, both of which incentivized being able to 91 00:05:54,400 --> 00:05:58,600 Speaker 1: detect pregnancy as soon as possible. At that time, the 92 00:05:58,600 --> 00:06:01,159 Speaker 1: best tests available had be sent away to a lab, 93 00:06:01,480 --> 00:06:04,599 Speaker 1: and we're only reliable for detecting pregnancy at six weeks 94 00:06:04,680 --> 00:06:08,280 Speaker 1: or later. The first home pregnancy test that's more or 95 00:06:08,320 --> 00:06:10,920 Speaker 1: less equivalent to the ones we know today was approved 96 00:06:10,920 --> 00:06:13,320 Speaker 1: for home use in nineteen seventy six and was on 97 00:06:13,400 --> 00:06:17,520 Speaker 1: store shelves by early night. With the sample of urine, 98 00:06:17,520 --> 00:06:20,159 Speaker 1: it could display a result within two hours, though it 99 00:06:20,240 --> 00:06:24,039 Speaker 1: wasn't as accurate as early as today's tests are. A 100 00:06:24,160 --> 00:06:27,640 Speaker 1: Modern pregnancy tests still involved detecting hc G, but have 101 00:06:27,760 --> 00:06:30,919 Speaker 1: gotten more sensitive, meaning they can detect smaller amounts of 102 00:06:30,920 --> 00:06:36,279 Speaker 1: it sooner in a pregnancy. Okay, a person's body starts 103 00:06:36,320 --> 00:06:40,919 Speaker 1: producing hCG when a fertilized egg implants itself, hopefully in 104 00:06:40,960 --> 00:06:44,039 Speaker 1: the prepared lining of the uterus. See our previous episode 105 00:06:44,040 --> 00:06:48,120 Speaker 1: on how human conception works for more on that, but basically, 106 00:06:48,360 --> 00:06:51,919 Speaker 1: under normal circumstances, a person will ovulate about a week 107 00:06:52,040 --> 00:06:56,320 Speaker 1: after their last period, and if that ovulated egg is fertilized, 108 00:06:56,440 --> 00:07:00,599 Speaker 1: it'll implant about a week after that. A so that's 109 00:07:00,640 --> 00:07:03,840 Speaker 1: two weeks into a pregnancy, because pregnancies are calculated from 110 00:07:03,880 --> 00:07:06,840 Speaker 1: the end of a person's last period, and that's when 111 00:07:06,880 --> 00:07:11,160 Speaker 1: the pregnant body starts producing hCG. The presence and or 112 00:07:11,280 --> 00:07:14,120 Speaker 1: levels of hCG in a person's body can be detected 113 00:07:14,160 --> 00:07:17,640 Speaker 1: in two ways, via blood test or via urine test. 114 00:07:18,800 --> 00:07:21,400 Speaker 1: A blood test is a little more accurate, but also 115 00:07:21,480 --> 00:07:24,960 Speaker 1: more invasive. You have to get blood drawn and often 116 00:07:25,080 --> 00:07:27,680 Speaker 1: more expensive. You have to go to a medical care 117 00:07:27,720 --> 00:07:30,240 Speaker 1: provider to get your blood drawn and send the sample 118 00:07:30,280 --> 00:07:33,480 Speaker 1: to a lab. But a blood test can detect the 119 00:07:33,480 --> 00:07:36,520 Speaker 1: presence or quantity of hCG in your blood as early 120 00:07:36,560 --> 00:07:39,120 Speaker 1: as two to three weeks into a pregnancy, and so 121 00:07:39,160 --> 00:07:41,640 Speaker 1: before you would have ever missed your period, though it 122 00:07:41,680 --> 00:07:43,280 Speaker 1: can take a day or more to get the lab 123 00:07:43,280 --> 00:07:46,920 Speaker 1: results back. A urine test is more common because even 124 00:07:46,920 --> 00:07:50,120 Speaker 1: though it's a little less accurate, especially early in a pregnancy, 125 00:07:50,400 --> 00:07:53,400 Speaker 1: it's cheaper, can be done anywhere, and the results are 126 00:07:53,400 --> 00:07:56,920 Speaker 1: pretty much immediate. These are done by either collecting a 127 00:07:56,920 --> 00:07:59,680 Speaker 1: sample of urine and dipping a testing strip into the sample, 128 00:08:00,120 --> 00:08:04,080 Speaker 1: or by urinating directly on a testing strip. A urine 129 00:08:04,120 --> 00:08:07,240 Speaker 1: test can generally detect the presence of hCG three to 130 00:08:07,360 --> 00:08:10,840 Speaker 1: four weeks into a pregnancy, so from slightly before to 131 00:08:11,080 --> 00:08:13,600 Speaker 1: right after you would have missed your period, and the 132 00:08:13,640 --> 00:08:17,400 Speaker 1: results develop on the strip within a few minutes. These 133 00:08:17,400 --> 00:08:19,880 Speaker 1: tests do very a little, so if you're taking one, 134 00:08:20,040 --> 00:08:23,600 Speaker 1: just read and follow the instructions, but rest assured that 135 00:08:23,640 --> 00:08:34,679 Speaker 1: there will be no rabbits, frogs, or barley involved. Today's 136 00:08:34,720 --> 00:08:37,000 Speaker 1: episode is based on the article how can a Rabbit 137 00:08:37,080 --> 00:08:39,040 Speaker 1: Tell Me If I'm pregnant? On how stuff works dot 138 00:08:39,040 --> 00:08:41,960 Speaker 1: com written by Robert Lamb. Brain Stuff It's production of 139 00:08:42,000 --> 00:08:44,240 Speaker 1: I Heart Radio in partnership with how stuff works dot Com, 140 00:08:44,320 --> 00:08:47,360 Speaker 1: and it's produced by Tyler Klang. Four more podcasts from 141 00:08:47,360 --> 00:08:50,440 Speaker 1: my heart Radio visit the iHeart Radio app, Apple Podcasts, 142 00:08:50,520 --> 00:08:52,319 Speaker 1: or wherever you listen to your favorite shows.