Infant Feeding & Early Development Puberty (IFED-2) Study

The more we know, the stronger babies will grow!

IFED Publications

Thanks to IFED participants, we have learned a lot about how babies grow! Publications using data from the original IFED study are listed below. You can click on each title to learn more about the paper.

If you want to learn more about the findings from IFED, please contact the IFED-2 study team! We are happy to share copies of published papers using the IFED data with you.


Characterization of ovarian development in girls from birth to 9 months

Authors: Chin HB, Baird DD, Kaplan SL, Darge K, Adgent MA, Ford EG, Rogan WJ, Stallings VA, Umbach DM.

Journal: Paediatr Perinat Epidemiol. 2021 Jan; 35(1):75-82.

Summary: This paper used ultrasound data from IFED infant girls to describe how ovaries grow during the first 9 months after birth. The authors found that the volume of the ovary grows quickly during the first 16 weeks after birth and then remains about the same size. This pattern of ovarian growth was similar in babies fed soy formula, cow’s milk-formula, and breastmilk. These data can be used in the future to help doctors and researchers understand how ovaries typically grow in healthy, term infants.

Endocrine-sensitive physical endpoints in newborns: ranges and predictors

Authors: Shah R, Alshaikh B, Schall JI, Kelly A, Ford E, Zemel BS, Umbach DM, Adgent M, Stallings VA.

Journal: Pediatr Res. 2021 Feb; 89(3):660-666.

Summary: This study used data from physical exams of male and female babies in IFED to describe the size of breast and reproductive tissues in healthy, term newborns. These data provide information about the range of size of different tissues shortly after birth, which may help doctors in the future to decide when babies need specialty evaluations.

Reproductive Hormone Concentrations and Associated Anatomical Responses: Does Soy Formula Affect Minipuberty in Boys?

Authors: Chin HB, Kelly A, Adgent MA, Patchel SA, James K, Vesper HW, Botelho JC, Chandler DW, Zemel BS, Schall JI, Ford EG, Darge K, Stallings VA, Baird DD, Rogan WJ, Umbach DM.

Journal: J Clin Endocrinol Metab. 2021 Aug; 106(9):2635-2645.

Summary: This study examined concentrations of reproductive hormones and growth of hormone-sensitive organs from birth to 7 months of age in male IFED infants fed soy formula, cow’s milk formula, and breastmilk. The authors found that hormone levels and growth of organs that respond to hormones were similar in boys fed formula made from soy, which has plant estrogens (female hormones), and boys fed formula made from cow’s milk.

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Incidental findings during ultrasound of thyroid, breast, testis, uterus and ovary in healthy term neonates

Authors: Calle-Toro JS, Kelly A, Ford EJ, Zemel BS, Schall JI, Adgent MA, Umbach DM, Rogan WJ, Stallings VA, Darge K, Kaplan SL.

Journal: J Ultrasound. 2019 Sep; 22(3):395-400.

Summary: When ultrasounds exams are used in adults and older children, anatomical differences in organs are sometimes found that otherwise would have gone unnoticed, which are called incidental findings. These differences may be normal, or they may be abnormal and require additional follow-up. Since infants do not usually have regular ultrasounds, it is not known how common incidental ultrasound findings are in this age group. Using ultrasound data from IFED infants, the authors found that regular ultrasound screening in infants occasionally uncovers organ differences, similar to what has been reported in older age groups.

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A Longitudinal Study of Estrogen-Responsive Tissues and Hormone Concentrations in Infants Fed Soy Formula

Authors: Adgent MA, Umbach DM, Zemel BS, Kelly A, Schall JI, Ford EG, James K, Darge K, Botelho JC, Vesper HW, Chandler DW, Nakamoto JM, Rogan WJ, Stallings VA.

Journal: J Clin Endocrinol Metab. 2018 May; 103(5):1899-1909.

Summary: This study used data from male and female infants in IFED to see if there are differences in concentrations of estrogen (female hormone) and the growth of organs that respond to estrogens in infants fed formula made from soy, which contains plant estrogens, compared to infants fed formula from cow’s milk or breastmilk. The uterus and vagina of newborn girls still show the effects of their mother's hormones that they were exposed to in the womb, and the authors found that infant girls fed soy formula lost these effects a little more slowly than the other girls. More studies are needed to understand if these differences affect health or long-term development. There were no differences in breast size or estrogen levels in males or females fed soy formula compared to other infants.

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Soy Formula and Epigenetic Modifications: Analysis of Vaginal Epithelial Cells from Infant Girls in the IFED Study

Authors: Harlid S, Adgent M, Jefferson WN, Panduri V, Umbach DM, Xu Z, Stallings VA, Williams CJ, Rogan WJ, Taylor JA.

Journal: Environ Health Perspect. 2017 Mar; 125(3):447-452.

Summary: DNA methylation can affect how a gene is expressed without causing any changes to the underlying genetic code. This study used IFED data to examine if there are differences in DNA methylation patterns in vaginal cells in girls fed formula from soymilk compared to girls fed formula from cow’s milk. The authors found some differences in DNA methylation in a specific gene in infant girls fed soy formula, which has plant estrogens, compared to girls fed cow’s milk formula. The role of this gene is not well understood, and it is not known if these differences continue after infancy or if they affect health or development in any way.

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Size of testes, ovaries, uterus and breast buds by ultrasound in healthy, full-term neonates ages 0-3 days

Authors: Kaplan SL, Christopher Edgar J, Ford EG, Adgent MA, Schall JI, Kelly A, Umbach DM, Rogan WJ, Stallings VA, Darge K.

Journal: Pediatr Radiol. 2016 Dec; 46(13):1837-1847.

Summary: Reproductive organs can change size soon after birth because newborns are no longer exposed to their mother's hormones like they were in the womb. Ultrasounds are not regularly conducted in newborn, so there is very little information about the range in size of these organs after birth. This study described the size of breast and reproductive organs in healthy, term newborns using data from ultrasounds conducted on IFED babies in the first 3 days after birth. This information may help create reference ranges for newborn reproductive development in the future, which can help doctors and researchers understand how babies typically develop and grow.

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