Soy-formula milk linked to menstrual pain: Study

Feeding female babies soy-based formula milk can increase their risk of suffering from severe pain during their menstrual cycle later in their lives, warns a new study.

The study found that young women – aged between 18 and 22 – who were fed soy formula as babies were 50 per cent more likely to have experienced moderate or severe menstrual discomfort or pain during their periods.

"Menstrual pain can substantially affect the quality of women's lives," said Kristen Upson, a postdoctoral student from the US National Institute of Environmental Health Sciences in the US.

"Exposure to oestrogens during infant development, such as the phytoestrogens in soy formula, may affect reproductive health in adulthood," said Upson.

For the study, the team examined 1,553 women aged between 23 and 35 among which a total of 198 (13 per cent) reported ever being fed soy formula milk.

The findings, published in the journal Human Reproduction, showed that soy formula-fed babies were 40 per cent more likely to have used hormonal contraception at some point in their adulthood to alleviate menstrual pain compared to women who had not been fed soy formula as babies.

The new results were in consistence with previous research that reported an increased risk of greater menstrual pain severity in adulthood with soy formula feeding.

Evidence from subsequent animal studies also support the disruptive effects of the soy formula phytoestrogen, genistein, on reproductive system development that persist into adulthood.

A greater understanding of hormonal exposures during periods of development that affect reproductive health in adulthood is needed to inform future prevention efforts and improve women's health, the researchers noted.