NIEHS postdoctoral researcher and lead author Kristen Upson, Ph.D., offered a potential explanation for the association between soy formula and severe menstrual pain. She said that data from previous laboratory animal studies suggest that early-life exposure to genistein, a naturally occurring component in soy formula, interferes with the development of the reproductive system, including factors involved in menstrual pain. She said these studies have also shown that developmental changes can continue into adulthood.
However, severe menstrual pain is not the only adverse reproductive health condition that Upson has linked to infant soy formula. She and her collaborators at the Fred Hutchinson Cancer Research Center in Seattle previously linked soy formula feeding to endometriosis, a condition where tissue that normally lines the inside of the uterus grows outside. Using SELF data, Upson and NIEHS senior scientist Donna Baird, Ph.D., have also linked infant soy formula to larger fibroids among woman with fibroids and to heavy menstrual bleeding.