Associations between urinary and follicular fluid concentrations of phthalate metabolites and reproductive outcomes in Brazilian women undergoing fertility treatment.

Existing literature indicates that phthalates can be toxic to the ovaries, negatively affecting female reproduction and potentially influencing outcomes in assisted reproductive technology (ART). However, data on associations between urinary and/or follicular fluid phthalate concentrations and ART outcomes in South American women are scarce. Therefore, in this prospective study, we recruited 93 women (n = 119 cycles) undergoing ART at a fertility clinic in Brazil. They provided urine and follicular fluid (FF) samples, from which we measured the concentrations of the 15 phthalate metabolites more frequently found in Brazilian populations. We documented both laboratorial and clinical outcomes, estimating associations using negative binomial regression. Our findings revealed that specific oocyte and embryo development parameters were associated with urinary concentrations of phthalate metabolite. Particularly, number of follicles, maturation, as well as blastulation were negatively associated with Mono-benzyl phthalate (MBzP). Similarly, urinary mono-ethyl phthalate (MEP) was associated with lower rates of maturation, good quality and blastulation. However, some parameters positively associated with mono-(carboxyisooctyl) phthalate (MCiOP), including maturation, good quality, and blastulation. We also observed certain associations between embryo development and FF concentrations of phthalate metabolite, although the magnitude and direction of these associations differed among various metabolites. Overall, our results suggest that urinary and FF concentrations of phthalate metabolite may be linked to altered outcomes in ART cycles. However, further studies are needed to clarify the extent of this impact. Our results support previous literature and is the first to evaluate urinary and FF phthalate metabolites concentrations in South American women undergoing infertility treatment.