New research suggests that infant girls fed soy formula are more likely to develop severe menstrual pain as young adults. The finding adds to the growing body of literature that suggests exposure to soy formula during early life may have detrimental effects on the reproductive system.
Researchers examined data from 1,553 African-American women, aged 23-35 years, participating in the US Study of Environment, Lifestyle, and Fibroids (SELF). Data on infant soy formula feeding was ascertained by self-administered questionnaire, with 89 per cent of participants receiving assistance from their mothers. Information on menstrual pain indicators was collected by web- and telephone-interview.
They found that women who had ever been fed soy formula as babies were 50 per cent more likely to have experienced moderate or severe menstrual discomfort between the ages of 18 and 22 years (relative risk [RR] 1.5; 95% CI 1.1-2.0) than unexposed women and were 40 per cent more likely to have used hormonal contraception to help alleviate menstrual pain (RR 1.4; 95% CI 1.1-1.9).
The results are consistent with the association observed in a previous study of young adults aged 20-34 years who had participated in formula feeding studies as infants.
The study appears online in the journal Human Reproduction.