Environmental phthalates and bisphenol a do not preferentially accumulate in human follicular fluid

Abstract

OBJECTIVE: To test the hypothesis that preferential accumulation of environmental phthalates and bisphenol A, present in medical plastics, occurs in the human ovarian microenvironmentDESIGN: Laboratory sample analysisMATERIALS AND METHODS: Discarded follicular fluid from 5 women exposed to medical plastics for 3 weeks while undergoing IVF was collected in 120 ml jars with Quinn's Advantage media during oocyte retrieval. The jars were submitted to AXYS labs (Sydney, B.C.) and extracted for phthalates and bisphenol A with AXYS method MLA-059 (Kato et al, Anal Chem 2005). Using High-Performance Liquid Chromatography, samples were measured for Monomethyl phthalate, Monoethyl phthalate, Mono-n-butyl phthalate, Monobenzyl phthalate, Mono-2-ethylhexyl phthalate, Mono-(2-ethyl-5-oxohexyl) phthalate, Mono-(2-ethyl-5-hydroxyhexyl) phthalate and Bisphenol A. One sample was spiked with the seven phthalates and four samples were spiked with d6 bisphenol A to serve as a control. Concentrations of phthalates and bisphenol A were compared to minimum levels in the literature shown to have a detrimental impact on in vitro oocytes from laboratory animals.RESULTS: All phthalates were detected at <15 ng/mL. The highest detectable phthalate concentration in the samples was 1/200 of the minimum level reported to have a detrimental impact on animal oocytes in vitro (Anas et al, Reprod Toxicol 2003). Bisphenol A was undetectable in all 5 patients (sensitivity < 0.27 ng/mL), similar to previously cited human follicular fluid levels ranging 1-2 ng/mL (Tsutsumi et al, J Steroid Biochem Mol Biol 2005).CONCLUSIONS: Phthalates and bisphenol A in human follicular fluid are present at 1/200 to 1/1000 of levels known to produce detrimental effects on oocyte maturation or ovarian steroidogenesis in vitro in laboratory animals. Continued investigation into harmful effects on female reproduction may be important, but further investigation into phthalates and bisphenol A disruption of human follicular maturation does not seem warranted. OBJECTIVE: To test the hypothesis that preferential accumulation of environmental phthalates and bisphenol A, present in medical plastics, occurs in the human ovarian microenvironment DESIGN: Laboratory sample analysis MATERIALS AND METHODS: Discarded follicular fluid from 5 women exposed to medical plastics for 3 weeks while undergoing IVF was collected in 120 ml jars with Quinn's Advantage media during oocyte retrieval. The jars were submitted to AXYS labs (Sydney, B.C.) and extracted for phthalates and bisphenol A with AXYS method MLA-059 (Kato et al, Anal Chem 2005). Using High-Performance Liquid Chromatography, samples were measured for Monomethyl phthalate, Monoethyl phthalate, Mono-n-butyl phthalate, Monobenzyl phthalate, Mono-2-ethylhexyl phthalate, Mono-(2-ethyl-5-oxohexyl) phthalate, Mono-(2-ethyl-5-hydroxyhexyl) phthalate and Bisphenol A. One sample was spiked with the seven phthalates and four samples were spiked with d6 bisphenol A to serve as a control. Concentrations of phthalates and bisphenol A were compared to minimum levels in the literature shown to have a detrimental impact on in vitro oocytes from laboratory animals. RESULTS: All phthalates were detected at <15 ng/mL. The highest detectable phthalate concentration in the samples was 1/200 of the minimum level reported to have a detrimental impact on animal oocytes in vitro (Anas et al, Reprod Toxicol 2003). Bisphenol A was undetectable in all 5 patients (sensitivity < 0.27 ng/mL), similar to previously cited human follicular fluid levels ranging 1-2 ng/mL (Tsutsumi et al, J Steroid Biochem Mol Biol 2005). CONCLUSIONS: Phthalates and bisphenol A in human follicular fluid are present at 1/200 to 1/1000 of levels known to produce detrimental effects on oocyte maturation or ovarian steroidogenesis in vitro in laboratory animals. Continued investigation into harmful effects on female reproduction may be important, but further investigation into phthalates and bisphenol A disruption of human follicular maturation does not seem warranted.