UCSD's "birth injury" experiments on rats must end!

Abominable experiments on female rats are being carried out at University of California, San Diego (UCSD) to purportedly study how prolonged labor can cause muscle injury to reproductive and neighboring organs, like the bowel and bladder.


Please send a letter to UCSD and officials at the National Institutes of Health (NIH) today to call for an end to these horrific experiments, and for them to be replaced with relevant, ethical human research.

The goal of the research is to develop a treatment for problems that arise from prolapsed organs following childbirth. It should be noted that in humans, pelvic floor disorders and related problems are not only linked to difficult births.

In unnatural and cruel animal experiments that have been going on for at least seven years, researchers subjected 3-month-old female rats to what they term a “simulated birth injury.”


A 130-gram weight was attached to a balloon catheter inserted into the vagina and left in place for 2 hours, after which a 5 ml balloon was pulled through the birth canal to simulate traumatic birth.

The use of 130-gram weights to simulate birth trauma is questionable when a newborn rat pup weighs only 6- 8 grams. In addition, this process is physiologically irrelevant, because a normal birth involves the release of specific hormones from the ovaries and placenta that are designed to relax ligaments and muscles in preparation for birth. In these rats, who weren’t really giving birth, those processes were absent.

After the injury procedure, a proprietary hydrogel was injected into the rats’ pelvic floor muscles to assess its effect on repairing the injury. A control group of rats was given saline. Later the rats are killed for dissection. To evaluate their experimental model with normal delivery, they also killed rats who were in the process of giving birth naturally.

All told, between the numerous categories of rats killed (pregnant, non-pregnant, and birthing), and those killed at varying intervals to dissect muscle specimens, along with the control groups, a great number of rats are subjected to considerable suffering and death for this research.


Scientists have already noted that the pelvic floor in humans is vastly different from four-legged animals, making their use in this research highly limited. Human-relevant methods for studying female pelvic floor disorders include computer and biomechanical models designed from 3D MRI scans of actual humans and a sophisticated microfluid device known as EVATAR that recreates the female reproductive organs in miniature, including biomechanical, cellular and hormonal interactions.

It’s time to stop inflicting suffering on innocent rats for flawed and inapplicable research to “simulate birth injury”. These experiments cost taxpayers $1.25 million in 2023 alone. Please send your letter today to call for an end to this cruel research.


Citizens for Alternatives to Animal Research and Experimentation (CAARE), is a 501(c)(3) non-profit organization, established to highlight and promote research without animals. 

Please donate to support CAARE’s mission to reduce animal suffering by disseminating information about the power and progress of research without animals.



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  • Barbara Stagno
    published this page in Action Alerts 2023-11-13 12:19:36 -0500