Chemicals 'may reduce fertility'

Exposure to perfluorinated chemicals (PFCs) could influence how long it takes for a woman to fall pregnant, they said.

Researchers led by a team from the University of California in Los Angeles analysed data from 1,240 women in Denmark recruited between 1996 and 2002 who went on to give birth. They measured the level of two of the most common PFCs, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), in the women's blood. They then asked the women how long it had taken them to conceive.

The average age of the women was 31, and 15% of the group were over 35, which is the age at which fertility is known to decline more rapidly. The study results were adjusted to take into account their age, lifestyle and socio-economic status.

The researchers found that women who needed infertility treatment or took longer than 12 months to conceive had higher levels of PFOS and PFOA than those who conceived in under six months. They estimated that women with the highest exposure to PFOS were in fact 70% to 134% more likely to suffer infertility (defined as taking longer than 12 months or requiring infertility treatment) than women with the lowest exposure.

Meanwhile, those with the highest levels of PFOA were 60% to 154% more likely to be infertile than women with the lowest exposure.

The researchers said no conclusions could be drawn from the study on how the chemicals may affect women who fail to get pregnant at all. But they said the effect of the chemicals on a man's sperm quality could impact on ability to conceive "since the couples may share similar aspects of lifestyle and around 99% of subjects in this cohort had a spouse or partner". However, they called for further studies to investigate the impact on sperm.

PFOA is widely used in manufacturing and industry, including the production of non-stick cookware, heat-resistant materials and those used in waterproof clothing. PFOS has been used to treat surfaces and upholstery, some insecticides and fire extinguisher foam, although its use has been steadily falling since the late 1990s.

The study was published online in the journal Human Reproduction.

Tony Rutherford, chair of the British Fertility Society, said the results were interesting. "This research shows a tenuous link in the delay to conception in women with the highest levels of two commonly used perfluorinated chemicals," he added. "This is an important finding and certainly warrants further detailed research, particularly in those trying for a family. This study emphasises the importance of remaining vigilant to potential environmental factors that may impact on fertility."