Association of organophosphate flame retardant metabolite concentrations in follicular fluid with in vitro fertilization outcomes among infertile women.

Organophosphorus flame retardants (OPFRs) are widely used endocrine-disrupting chemicals; however, the influence of OPFRs in follicular fluid (FF) on early in vitro fertilization (IVF) outcomes remains unexplored. This study investigated the associations between OPFR metabolite (mOPFR) concentrations in FF and early IVF outcomes among 155 infertile women. Multivariate linear regression revealed negative associations between the concentrations of total mOPFRs in FF with the number of oocytes retrieved (β = -0.63, 95 % CI: -1.01 to -0.25, p = 0.001), between bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) with the number of oocytes retrieved (β = -0.84, 95 % CI: -1.47 to -0.21, p = 0.009), and between bis(2-chloroethyl) phosphate (DBP) with the rate of high-quality day-3 embryos (β = -6.01, 95 % CI: -11.54 to -0.48, p = 0.033). The Bayesian kernel machine regression (BKMR) model identified BDCIPP as the dominant risk factor (posterior inclusion probability = 0.97) among five mOPFRs, corroborating the result of weighted quantile sum (WQS) models. Our findings revealed that BDCIPP in FF is a critical risk factor for the reduced number of oocytes retrieved, emphasizing that further research should focus on BDCIPP when exploring the effects of OPFR exposure on pregnancy outcomes. This study indicated that targeted policies and safe reproductive health strategies are warranted.