The rabbit test was a form of "bioassay
" pregnancy test
developed in the late 1920s. When a woman is pregnant she produces a hormone called human chorionic gonadotropin
. Its function is to keep the placenta
from rejecting an embryo
. Human chorionic gonadotropin also gets excreted in urine
. If the urine is then injected into a (female) rabbit and human chorionic gonadotropin is present, the rabbit's ovaries will manifest bulging masses (i.e., corpora hemorrhagica). A few days after the urine is injected, the rabbit is euthanized and dissected. The doctor examines the ovaries.
There's a popular misconception that pregnancy
via the rabbit test was determined whether the bunny lived or died. Death indicated the woman was pregnant. This is not true. In fact, since dissection
was the preferred method of ovary examination, the rabbit always died regardless if the human woman was pregnant or not. This misconception lead to "the rabbit died
" entering popular speech as a euphemism
for "she got knocked up
Modern pregnancy tests (like the HPT
) still look for human chorionic gonadotropin, however, they do so directly, ensuring there finally came a day no rabbits would die.
* * *
Rabbit Test is also a bad 1978 movie directed by Joan Rivers
and starring Billy Crystal
. Crystal plays a man who gets pregnant. Roddy McDowall
plays Crystal's gynecologist
. That creeps me out a little.