Pregnant Mares and HRT – The Bad News Keeps on Coming

Written by JANE ALLIN
Chief Research Analyst

Expendable Flyer re Premarin and Prempro
Expendable Flyer re Premarin and Prempro

Conventional HRT such as Premarin® and Prempro® is manufactured from conjugated equine estrogens (CEEs) extracted from pregnant mare’s urine. To produce these drugs, the pregnant mares are confined for 6 months connected to a urine collection device which chaffs their flanks and can induce inflammation and severe infections. To add to this discomfort, they are housed in stalls so small that they have difficulty lying down or turning around. A sorry and tedious life indeed.

Once they foal, they are re-impregnated immediately simply to start a cycle of torment they must endure for the rest of their lives. Foals are the by-products of this atrocious industry and most are either fattened for slaughter on feedlots or go directly to meat auctions. This is the same fate of the spent mares or those who are unsuccessful breeders.

Statistics indicate that a filly foal has less than 1 in 10 chance of not going to slaughter, and worse, a colt foal, less than 1 in 50.

As far back as the 1970’s, the negative implications of equine-based HRT were apparent. Several studies at that time linked the use of Premarin® to both increased incidences of heart disease and cancer. By the time the first results from the WHI (Woman’s Health Initiative) were released, the combination (estrogen + progestin) drug, Prempro®, had been in widespread use since its approval in 1995. This drug proved to be even deadlier than the estrogen-only Premarin®.

Since this time conventional equine based HRT has been increasingly linked to more and more complications from its use – all life threatening with potential death sentences to those who chose to take it to relieve symptoms of menopause. In addition to increased incidences of breast, uterine and lung cancer, cardiac disease, pulmonary embolisms, blood clots, asthma, malignant melanoma, reduced insulin resistance, and Alzheimer’s, among other disorders, recent data has shown that those who take this toxic potion are now at a 29% increased risk in ovarian cancer.

Will the list ever end?

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2 thoughts on “Pregnant Mares and HRT – The Bad News Keeps on Coming”

  1. I would not take premarin if you paid me…i had a hysterectomy and became instantly post menopausal with all the attendant hot flashes and other issues and my doctor and i found other ways to deal with least to the point where i could cope with them…he did not want to prescribe hormones due to the risks and i did not want a horse to suffer for me. More doctors and more women need to explore alternative therapies for menopause…not all women have symptoms anyway and some are mild and transitory..and there are other drugs and some natural products that do work. No animal should be made to suffer this way, year in and year out. When I was a teen, the stable I rode at had a couple of mares that were used this way, in small standing stalls, wearing their harnesses, pregnant and unable to move…it broke my heart to see them then…even though I did not truly understand the issues at that time…I do now.


  2. women need to be educated about plant estrogens, especially soy and menopausal symptoms. i have had no hot flashes etc. the drug companies know of the dangers to women & cruelty to these innocent horses and they keep pushing prempro/premarin.


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