Sir: The risk of transmission of Creutzfeldt-Jakob disease to people treated with growth hormone derived from cadaver pituitaries is well known ('Children's growth hormone made from glands of infected corpses', 16 August). Yet in Britain nothing has been heard of patients who received gonadotrophins (fertility drugs) derived from pituitaries as treatment for infertility, although the gonadotrophins were obtained from the residue of the cadaver pituitaries from which the growth hormone had been extracted. Gonadotrophins derived from cadaver pituitary glands were used experimentally in Britain during the Sixties and early Seventies, when they were replaced in favour of human menopausal gonadotrophin. There is no evidence that CJD can be transmitted by human menopausal gonadotrophin, which is derived from urine.
Two Australian women are known to have died of CJD after receiving injections of gonadotrophin derived from human pituitary as a treatment for infertility. Assuming that the incubation period is 12 to 14 years, the possibility exists that in the Seventies women died of CJD but the cause of death was incorrectly attributed.