Peggy, a rescued PMU Mare. PMU factory farmers freeze-brand the stall numbers on the mares. They have no names, just numbers.


Pregnant Mares’ Urine (PMU) Industry

PMU is used to produce estrogen and hormone-replacement drugs such as Premarin, Prempro, and Premphase, and DUAVEE, a “Prempro Lite” which contains Premarin. PMU drugs are made by keeping mares constantly pregnant and collecting their estrogen-rich urine. 

The 2002 Women’s Health Initiative (WHI)—a major landmark study—concluded that the use of PMU drugs increases the risks of breast cancer, heart disease, heart attacks, strokes, blood clots, and dementia. At the time, many doctors in the United States and Canada stopped prescribing PMU drugs once the dangers were fully known. However, Pfizer (and Wyeth before it) saw what was coming down the pike and began moving production abroad where local regulations are more lax, and there are significantly fewer FDA inspectors available to monitor production. Reportedly, this not only results in significantly more horrific conditions for the mares but also less oversight in the manufacturing of an already dangerous drug. There are reportedly 90,000 mares currently on PMU lines in China.

Two decades after the WHI, Pfizer is still making around $1 billion a year from their PMU products – the vast majority of which comes from the U.S. market. Many women, even some doctors, are not aware today of the potential dangers of these drugs. Pfizer continues to settle lawsuits and pay out money to individuals who have gotten sick from PMU drugs and to the families of those who have died. At the same time, they spend huge amounts of money marketing these drugs in magazines and television ads across the country. Read more under “What You Can Do” below, but we believe that a boycott of all Pfizer’s commercial and pharmaceutical products, wherever possible, is the best way to get action by cutting into Pfizer’s profits. It sends a very strong message!

More information:


Video Presentations:

Vicki Burns, Conservationist and Animal Advocate, formerly of the Winnipeg Humane Society, spoke at our 2015 American Equine Summit. Her talk is titled “Shining a Light on the PMU Industry – What is Hidden Behind the Barn Doors?”

Jerilynn C. Prior, MD FRCPC, Professor of Endocrinology at the Department of Medicine at the Centre for Menstrual Cycle and Ovulation Research at the University of British Columbia Vancouver Coastal Health Research Institute, spoke at our 2015 American Equine Summit. Her talk is titled “An Approach to Estrogen Appropriate for the 21st Century.”

Retired Canadian Physician Dr. Ray Kellosalmi was among the first to come out publicly against the use of Premarin and stop prescribing it to his patients. Here is an eye-opening presentation on PMU that Dr. Kellosalmi gave at our 2014 American Equine Summit entitled “Horse Slaughter & PMU: Shared Disgrace, Shared Challenge.”


DUAVEE, a new “Prempro-Lite” Drug

With all the bad publicity and increasing awareness of the dangers of PMU drugs, we thought this awful practice would surely come to an end, but it didn’t, and then the FDA approved Pfizer’s DUAVEE (formerly known as Aprela) in October 2013. Although heavily disguised in both name and labeling, DUAVEE is nothing more than “Prempro Lite” that carries the same dangerous side effects, contains Premarin, and is not only made in the same inhumane way, but also contains bazedoxifene, which is not even approved as a stand-alone drug by the FDA in the U.S.

Oh, what a tangled web we weave,
When first we practice to deceive!

This well-known quotation was aptly used to condemn the pharmaceutical giant Wyeth in a riveting article published in 2002 by the Canadian Medical Association Journal (CMAJ), widely regarded as the most highly respected medical publication in Canada. It added, “…the message for healthy women without severe symptoms of menopause is now clear: To avoid as far as possible HRT, which on balance does more harm than good…”

Cycle of cruelty

Life for PMU mares in Canada was brutal and we can only imagine that it is even worse in China where there is little to no oversight. The mares are repeatedly impregnated and for six months of each 11-month pregnancy, most are confined in stalls that prohibit turning around, grooming themselves, and comfortably lying down. Their water intake is often regulated to produce maximum estrogen-rich urine. The mares are continually attached to plumbing which is designed to fit over their urethras. It is held in place with movement-restricting body straps. When mares can no longer adequately “produce,” most are sold for slaughter. Most of their surviving foals are either pulled and raised as “Pee Line” replacements or slaughtered for food.

A former PMU mare Peggy (left) was part of a major rescue operation of 46 Canadian PMU mares that Equine Advocates saved in Manitoba between October 2003 and March 2004. Peggy’s brand, the number 157, corresponds to the number on her stall where she had to stand for more than six months of every year while pregnant.

Will we live to see the end of PMU lines?

The Food & Drug Administration (FDA)

PMU drugs were first approved by the FDA in 1942 followed by Prempro, Premphase, PMU creams, patches, and DUAVEE, which hit the market in 2014. PMU drugs contain impurities and unknown properties that cannot be identified. Bioidentical hormones are regarded by many medical professionals to be much safer while not involving the use and abuse of horses to produce them. There are numerous other doctor-recommended medications on the market that women can use to effectively treat the symptoms of menopause that are safely produced in laboratories—and whose ingredients can be completely identified. Note: Equine Advocates is not endorsing or recommending any particular medication. All questions of a medical nature should be taken up with your doctor.

What a crew! All the mares in this photo either came from PMU factory farm operations in Canada or are the offspring of those mares and were born in the U.S.