MedicalResearch.com Interview with: Kristen Upson, PhD, MPH and Donna D. Baird, PhD Epidemiology Branch National Institute of Environmental Health Sciences Research Triangle Park, NC 27709  MedicalResearch.com: What is the background for this study? What are the main findings?  Response: Menstrual pain is the most common menstrual complaint and can substantially affect the quality of women’s lives. A prior study in young adults who participated in feeding studies as infants reported an increased risk of greater menstrual pain severity in adulthood with soy formula feeding. Since that study, evidence from laboratory animal studies support the disruptive effects of a phytoestrogen present in soy formula, genistein, on reproductive system development, including aspects involved in menstrual pain. The laboratory animal studies also demonstrate that the developmental changes with genistein can persist into adulthood. Given these results, we were interested in further evaluating the association between infant soy formula feeding and menstrual pain in a cohort of young women. In our study of women ages 23-35 years old, we observed that soy formula feeding during infancy was associated with several indicators of severe menstrual pain in reproductive-age women. This included a 40% increased risk of ever using hormonal contraception for menstrual pain and 50% increased risk of moderate/severe menstrual discomfort with most periods during early adulthood.  (more…)