Iron deficiency during ⁤pregnancy can affect sex organ development in mice

⁤ Updated June 13, 2025

Iron deficiency during pregnancy in mice can lead to male embryos developing female sex organs, according to a new study. The ⁤research, published in Nature, reveals that low iron levels disrupt the activation of a critical gene responsible for triggering the development of male sex organs.

Specifically, the iron deficiency interferes wiht⁣ the function of the enzyme ⁢JMJD1A, which is essential for activating the SRY gene, the “master switch” for male sex determination. when iron is lacking, JMJD1A cannot properly remove histones—proteins that suppress gene expression—from the SRY gene, effectively blocking its activation.

Peter Koopman, professor emeritus of developmental biology at the University of Queensland in Australia, described the finding as “entirely new ‍and totally unexpected.” He added, “ItS never ‍been shown before that iron can flip such an crucial developmental switch.”

In the study, researchers manipulated iron levels in pregnant mice through diet and pharmaceutical treatments. They found that iron deficiency lead to six out of 39 XY embryos developing ovaries instead ‍of testes. Further investigation suggested that genetics play a role in ⁤determining which embryos are susceptible to this effect.

To confirm the mechanism, the team ‍also grew embryonic gonads in lab dishes, allowing them to directly observe the impact of iron depletion. Reducing iron levels in cells to 40% of normal resulted⁢ in a critically important increase in histones on the SRY gene, effectively silencing it.

The findings suggest that nutrition and metabolic⁤ factors‍ can significantly impact ‍developmental traits ⁢previously thought to ‍be purely genetically controlled, Koopman ‍said. He speculated that other organ systems might also depend on iron or other dietary factors in a similar way.

Tony Gamble, an associate professor⁣ of biological sciences ⁣at⁣ Marquette University, who was not involved in the study, cautioned that it is indeed too early to determine whether these findings in mice translate to human pregnancy and sex development. While sex determination processes are broadly similar across mammals,‍ ther are important differences⁤ between mice⁢ and humans.

Testing⁤ these findings in humans presents ethical challenges, ‍Koopman said. Future research will likely involve biochemical, cell culture, and gene expression experiments to‍ build indirect evidence supporting the relevance of these findings to humans.

What’s next

Further research is needed to determine if iron deficiency during ⁣pregnancy has similar effects on sex organ development in⁣ humans. ⁢Studies are needed to determine if maintaining adequate iron levels during pregnancy can help ensure‍ proper development.