Response to Letter to the Editor on “Associations between urinary biomarkers of phthalates and phthalate alternatives and female sexual function in a North American cohort”

We thank the Editor for the opportunity to respond to this Letter to the Editor regarding our recently published manuscript on phthalate exposure and sexual function in Pregnancy Study Online (PRESTO) and to the author for their thoughtful commentary on our paper. Female sexual function is an important yet understudied outcome in the environmental health field. Characterizing the effects of environmental exposures—such as endocrine-disrupting chemicals (EDCs)—offers a unique opportunity to identify novel factors influencing sexual function, thereby improving public health and clinical practice. Recent epidemiological investigations, including our own, have sought to fill this critical literature gap. The author raises several valid methodological limitations of our study—we agree with these limitations and describe them as such in the Discussion of our manuscript. Our study nevertheless improves on previous studies of phthalates and female sexual function in its exposure assessment (serial urine samples), adjustment for multiple important confounders, and assessment of sexual function using a modified version of a validated instrument (Female Sexual Function Index-6 [FSFI-6]). This modified version of the FSFI-6 allowed us to use a question on lubrication difficulty (rather than lubrication frequency) from the full FSFI-19 that was highly correlated with the original question and appeared potentially more specific for sexual dysfunction in this population.1