Abstract Body
Background/Aim: Parabens are antimicrobial preservatives with widespread exposure, and may affect endocrine function. Few studies have evaluated their influence on fecundability. Our aim was to determine the association between parabens and fecundability among a cohort of women with one or two prior pregnancy losses who were trying to conceive. Methods: The EAGeR trial followed women who were trying to conceive for up to 6 cycles. Six parabens (benzyl, butyl, ethyl, heptyl, methyl, propyl) and four paraben metabolites (OH-methyl, OH-ethyl, 4-hydroxybenzoic acid [4-HB] and 3,4-dihydroxybenzoic acid [3,4-DHB]) were measured as pools combining three consecutive days of spot urine samples, at baseline, from 1185 women. Urinary creatinine was measured on day 1 of the pool. Fecundability, defined as time to pregnancy, was measured as number of menstrual cycles to achieve hCG positive pregnancy. Fecundability odds ratios (FORs) were determined by discrete-time survival analysis to model the association between fecundability and each chemical, adjusting for age, race/ethnicity, body mass index, creatinine, nulliparity and smoking, and accounting for left truncation (time trying prior to study enrollment). Quantile g-computation was used to estimate the effect of increasing all parabens by one quantile, in relation to fecundability. Results: Parabens were weakly (ethyl:heptyl rho -0.04) to highly (propyl:methyl rho 0.82) correlated with each other. Results were largely null in single chemical models, for example, butyl paraben FOR=0.99, 95% CI 0.95-1.03, per 1-log unit increase. Propyl paraben was marginally associated with reduced fecundability (FOR=0.96, 95% CI 0.92-1.01) and heptyl paraben with increased fecundability (FOR=1.15, 95% CI 1.00-1.33). Together as a mixture, parabens were not associated with fecundability (FOR=0.91, 95% CI 0.77-1.08).Conclusion: In single chemical models and as a mixture, most parabens were not associated with fecundability. While this is reassuring, given the high exposure prevalence, future studies should consider mixtures across endocrine disrupting chemical classes.
