International Association Against Painful Experiments on Animals

101 Misleading results from Vivisection Animal Experiments

82: Dog Deaths Deny Women Contraceptive Option

During the 1960s, doctors noticed that women receiving the steroid drug Depo-Provera as a treatment for premature labour, experienced a delay in the return of fertility after the birth of their babies. The observation led to clinical trials of the drug as a possible long-acting contraceptive.(1) Injectable preparations of Depo-Provera are now known to be as effective as oral contraceptives and are available in Europe, Asia, Africa and the Far East. In America however, approval was delayed for many years.(2)

Much of the controversy surrounding Depo-Provera relates to experiments with beagle dogs that indicated a host of disturbing side-effects.(2) There were abnormal growth problems, cases of breast cancer, and many animals died of pyometra, a condition in which pus accumulates in the uterus. None of these effects have been observed in women taking Depo-Provera(1,2) and scientists point to physiological differences between human beings and dogs which make beagles especially sensitive to certain kinds of steroids.(1)

High doses of Depo-Provera can also cause cancer in monkeys but again their relevance has been questioned since the tumours arise from a type of cell not found in women. Furthermore, the kind of cancer produced in monkeys is successfully treated by Depo-Provera in women!(1)

In 1991 an editorial in the Lancet entitled "DMPA (Depo-Provera) and breast cancer: the dog has had its day", argued that "Countries such as the USA, Australia and Japan would do well to reassess their existing policies on injectable preparations, otherwise they may deprive their female citizens of a reliable, effective and safe method of contraception."(2) One year later, America's Food & Drug Administration finally decided to approve Depo-Provera as a long acting contraceptive.


1) Bulletin of the World Health Organisation, 1982, vol.60, 199-210.
2) Lancet, 1991, October 5, 856-857.

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