Soy formula for baby girls linked to menstrual pain risks

A new study has brought warnings to parents who feed their baby girls with soy formula, suggesting that infant girls fed with soy formula are more likely to have severe menstrual pain as young adults.

The study published in this week's Human Reproduction journal showed that women who had ever been fed soy formula as babies were 50 percent more likely to have experienced moderate or severe menstrual discomfort between the ages of 18 and 22, and 40 percent more likely to have used hormonal contraception to help alleviate menstrual pain.

Researchers at the National Institute of Environmental Health Sciences (NIEHS) in the United States, along with those from Vanderbilt University Medical Center and the Henry Ford Health System, examined data from 1,553 African-American women, aged 23 to 35.

NIEHS postdoctoral researcher and lead author Kristen Upson said that data from previous lab animal studies suggested that early-life exposure to genistein, a naturally occurring component in soy formula, interfered with the development of the reproductive system, including factors involved in menstrual pain.

Those studies had also shown that developmental changes can continue into adulthood.

In addition, Upson linked infant soy formula to endometriosis, a condition where the tissue that normally lines the inside of the uterus grows outside, and larger fibroids among woman with fibroid.

Other studies by NIEHS scientists found that girl infants fed with soy formula had changes in the cells of the vagina, including differences in how specific genes are turned on and off.

The American Academy of Pediatrics (AAP) does not recommend soy formula for babies born prematurely. For full-term infants, the AAP recommends soy formula in rare cases where the child's body cannot break down the sugars in milk or if the family prefers a vegetarian diet.