Some suspected endocrine disruptors alter ovarian function and may contribute to female infertility

A new study from FREIA, published in Environmental Research, explored the association between potential endocrine disrupting chemicals (EDCs) and female fertility in women attending fertility clinics in Sweden and Estonia.

Up to 1 in 6 women experience difficulties becoming pregnant or carrying pregnancy to term. Despite the increasing use of assisted reproductive technologies (ART), the success rates of these treatments remained the same.

Ovarian disorders are the cause for infertility in about 1 in 4 couples. The ovaries play an important role in hormone production and formation of oocytes (“eggs”). It is therefore reasonable to assume that human-made chemicals that disrupt the hormone system, i.e. endocrine disrupting chemicals or EDCs, contribute to the rates of infertility.

In this FREIA study, levels of 59 known and suspected EDCs were analysed in follicular fluid, the biological fluid surrounding oocytes, of 185 Swedish women and 148 Estonian women undergoing fertility treatment. Multiple chemicals were detected in all follicular fluids. In >90% of the follicular fluids, 3 metabolites of the phthalate DEHP, methylparaben, and 6 PFAS (PFOS, PFOA, PFHxS, PFUnDA, PFNA and PFDA) were detected and used to link with female fertility parameters.

The ovaries of women with higher levels of DEHP, methylparaben and possibly PFUnDA and PFOA responded less to fertility treatment, established by calculating the ovarian sensitivity index (OSI). There were indications that some PFAS lowered the success of fertility treatment, determined by chance of establishing a pregnancy or live birth.

Overall, this study provides additional evidence that DEHP can negatively influence female fertility. In addition, several other chemicals, i.e. methylparaben and some PFAS, were identified that may harm ovarian function and contribute to female infertility.

This study adds to the increasing evidence that EDCs can contribute to female infertility and warrants interventions to lower exposures.