Laboratory study measures effects of phthalate exposure in pregnancy


Published 09 June 2023

Exposure of mice to endocrine disrupting chemicals in pregnancy suggests that EDCs may not just have a direct effect on reproductive function in women but may extend that effect over subsequent generations.

A laboratory experiment in mice reflects the extent to which female fertility may be adversely affected by endocrine disrupting chemicals (EDCs), and notably phthalates, those ubiquitous synthetic chemicals used as plasticisers and stabilisers in a multitude of consumer products. It’s already known, said investigator Jodi Flaws from the University of Illinois, that EDCs can have a catastrophic effect on male fertility, and may inhibit ovarian follicle growth in females, yet ‘limited information is available about the effects of environmentally relevant phthalate mixtures on female reproduction’.

To give an indication of where those effects might lie, Comer described a series of experiments in which pregnant mice were orally dosed with a control (corn oil) or a daily phthalate mixture (of six phthalates) given from gestational day 10 to birth. Comer emphasised that the mixture was based on urinary phthalate metabolite levels measured in pregnant women in the USA and would therefore reflect real-time exposure, even in the mouse model. Females born to these mice were then used to create a second generation by mating them with unexposed males, and these again were used to create a third generation by mating them with unexposed males.

By monitoring estrous cyclicity and fertility indices along the way, findings showed that prenatal exposure to the phthalate mixture significantly decreased anogenital distance (a marker of endocrine disruptor effect), testosterone levels, and litter size, and significantly increased abnormal estrous cyclicity, uterine weight, the number of cystic ovaries, and FSH and LH levels, over the initial control generation. These adverse changes were evident in all three generations of phthalate mice. The findings, said Flaws, albeit in mice, suggest that prenatal exposure to EDCs may not just have a direct effect on reprodutive function in women but may extend that effect transgenerationally.

A summit meeting with expert presentations hosted by ESHRE now lies behind recommendations made by the Society to protect human fertility from the effects of environmental pollutants.(1) Among the recommendations of the meeting were data collection and pre-conceptional health campaigns, but above all more legislative and political action. Aimed at policy-makers, the recommendations have been drawn up in response to the well established link between widespread infertility and exposure to hazards such as climate change, pollutants, HDCs, and toxic substances.

1. https://www.eshre.eu/Education/Environmental-Seminar

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