PFAS (Per- and Polyfluoroalkyl Substances)

PFAS are persistent 'forever chemicals' that bioaccumulate in human serum for years to decades (half-lives of roughly 3–8 years). In women, prospective preconception cohorts associate higher serum PFAS concentrations with reduced fecundability — meaning a lower chance of conceiving in any given cycle and a longer time-to-pregnancy. Studies also link elevated PFAS to lower anti-Müllerian hormone (AMH) and other markers of diminished ovarian reserve, as well as to irregular or longer menstrual cycles and earlier menopause. PFAS appear to interfere with ovarian steroidogenesis and hormone signaling. Because exposure is cumulative and widespread (including via contaminated drinking water), the body burden built up before conception is the relevant exposure.