A study carried out on mice which models the effects of soy-based baby formula on human infants has found that exposure to oestrogen can affect the fertility of the adult female. Exposure of unborn mice to phytoestrogen (plant oestrogen) genistein results in complete female infertility. This finding may help to explain female infertility – causes of which are failure to ovulate, the reduced ability of the oviduct to support embryo develop before implantation in the womb and failure of the uterus to allow embryo implantation.

The research, carried out by a team including Wendy N. Jefferson, a researcher in the lab of Carmen J. Williams at the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health, shows that the reason for this is the altered immune system response, which essentially fails to support embryo development.

The window for the alteration of the mucosal immune response in mice is only during the neonatal period, but in humans the development of the reproductive tract continues in until the onset of puberty, leading the authors to suggest limiting use of soya-based baby formulas.

Source: Biology of Reproduction

First published in May 2012

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