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Fetal Cells Remain With Mom for Life – And May Protect Against Disease

A mother’s child lives in her heart forever. The precious curls, the adorable gurgling laugh or the soft curve of a baby’s cheek can etch themselves in a woman’s mind long after her baby has left for college. But new research is beginning to understand ways in which this connection is more literal, more fascinating, and perhaps even beneficial to a mother’s health.

During pregnancy, fetal cells enter the mother’s bloodstream through the placenta. “The human placenta is one of the most invasive placentas,” in comparison to other animals, says Dr. Hillary Gammill, a fetal medicine expert at the University of Washington in Seattle. Those cells circulate throughout the mother’s body – and they don’t leave. They distribute themselves all over her systems and become incorporated into her organs, a process called fetal microchimerism. While earlier studies had associated theses cells with health problems, researchers are now finding evidence that these fetal cells can also be protective. While the mechanism isn’t fully understood, fetal cells are associated with reduced breast cancer. “Whether a fetal cell has a beneficial or detrimental effect partially depends on what kind of cell it develops into, but moreso on how the mother’s body responds to having those extra cells around.” explains Amy Boddy, Ph.D., a researcher at Arizona State University’s Department of Psychology who has studied fetal microchimerism for years. (Check out this video featuring Dr. Boddy and an introduction to fetal microchimerism.)

The placental exchange goes both ways. Cells from the mother enter the fetus as well, becoming part of the growing body and remaining for the rest of the child’s life. Perhaps even passing down to the next generation, living on in grandchildren. Siblings can also participate in this cellular sharing.  Cells that a fetus leaves in the mother’s body can be passed to younger sibling during a subsequent pregnancy.

Listen to NPR’s Michaeleen Doucleff explore this subject:

Or read the article at NPR.



Richard Harth, “The alien within: Fetal cells influence maternal health during pregnancy (and long after).” EurekaAlert. American Association for the Advancement of Science (AAAS),  28 August, 2015

Nicole Makris, “Fetus’ Cells Hang Around In Mother Long After Birth.” Healthline. Healthline, 6 September, 2015

Michael Doucleff, “Fetal Cells May Protect Mom From Disease Long After The Baby’s Born.” Shots Health News from NPR. NPR, 26, October, 2015

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Alison Relyea-Parr

Alison Relyea-Parr

Alison is the editor and contributor of A UW-Madison graduate, Alison is also an illustrator and educator.