Menstrual cycle characteristics and reproductive hormone levels in women exposed to atrazine in drinking water

► Atrazine is the most commonly used herbicide in the U.S. and a groundwater contaminant. ► We examined the relationship between atrazine and menstrual cycle function. ► Atrazine was observed at levels below the US EPA MCL. ► Atrazine was associated with menstrual cycle irregularity and altered hormones.