The study found infants fed soy-based formula experienced worse menstrual pain later in life
Soy-based formula in infants can cause increased menstrual pain years later.
A recent study to investigate this link looks at data from 1,553 women between the ages of 23 and 35 who were enrolled in Environmental Studies, Lifestyle & Fibroids in the United States between 2010 and 2012. These are published today in Human Reproduction, one of the world's leading reproductive medicine journals , researcher. 198 (13%) reported having been given soy formula.
They found that women who had been given soy formula when babies were 40% more likely to use hormonal contraception at some point to reduce menstrual pain compared to women who had not been given soy formula as a baby; between the ages of 18 and 22 they are 50% more likely to experience moderate or severe menstrual discomfort or pain with most of their menstruation.
"Many studies of menstrual pain do not include women on hormonal contraception, but this can exclude those who are most affected by menstrual pain because they might use drugs to reduce pain"
Dr Kristen Upson, a postdoctoral fellow at the Epidemiology Branch at the National Institute of US Environmental Health (NIEHS) in the National Institutes of Health (NIH), North Carolina, said: "Menstrual pain is the most common menstrual complaint and can substantially affect quality of life for women. Estrogen exposure during baby's development, such as phytoestrogens in soy formula, can affect reproductive health in adulthood.
When enrolled in the study, participants were asked whether they were given soy formula as a baby, how long and whether it started in the first two months of birth. They were encouraged to ask their mother to help them complete the questionnaire and 89% received their mother's help.
Participants were also interviewed on the telephone and asked if they had taken prescription or over-the-counter medications, including hormonal contraception, to treat or prevent menstrual cramps, pelvic pain or discomfort, age at the time of treatment, and whether they were still using it. They were asked about the use of birth control pills, hormonal implants, fillings, rings or injections, and intrauterine devices, the age they started using, and the reasons for their use. The researchers also asked participants about the frequency of moderate or severe menstrual discomfort between the ages of 18 and 22.
Co-author, Dr. Donna Baird, who is a senior researcher at the NIEHS / NIH and leads the Women's Health Group at the Epidemiology Branch at the NIEHS, said: "Many studies of menstrual pain exclude women on hormonal contraception, but this can exclude them mostly being disturbed by menstrual pain they may use drugs to reduce pain. Our question about previous women's experiences with menstrual pain allowed us to include all women in the study. "