Why a Fetus is Not Rejected Like a Foreign Body? - as part of the news series by GeoBeats.

Our bodies naturally tend to reject foreign body and scientists have long tried to answer the question why a fetus is not rejected within a woman's body.

New York University researchers recently performed a study to examine that issue.

When a foreign body is detected, our immune systems produce chemokines, which bind with other immune cells, and are sent to the site of inflammation to attack the intruder.


While in the womb, the foreign tissue of the fetus comes in contact with the immune cells of the mother, but does not react the same way as a transplanted organ would.

The study focused on the barrier that exists surrounding the fetus and placenta called the decidua, and found that during pregnancy, the decidua is subject to a genetic change, which causes the immune cells to not activate as they normally would with the presence of a foreign tissue.

The lead investigator commented: "This is a very exciting finding for us because it gives a satisfying explanation for why the fetus isn't rejected during pregnancy, which is a fundamental question for the medical community with clear implications for human pregnancy.”