Smoking can affect the placenta of expectant mothers, even after stopping smoking.

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CLOSON / ISOPIX / SIPA

Tobacco consumption, even when it is stopped before pregnancy, can have consequences on the placenta of pregnant women, shows a French study published this Wednesday, October 7.

Researchers from Inserm, CNRS and the University of Grenoble Alpes (UGA) studied the placental DNA of 568 women divided into three categories: non-smokers, women who quit in the three months preceding pregnancy or who had continued to smoke before and during their pregnancy.

In smokers, scientists have observed so-called “epigenetic” alterations in 178 regions of the placental genome (the DNA sequence is not altered, but the way genes are expressed may be affected).

In former smokers, these alterations are much less numerous but have nevertheless been found in 26 regions, shows their article published in the scientific journal 

BMC Medicine

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"The mechanisms involved are still poorly understood"

The placenta would therefore retain the “memory” of exposure to tobacco in women before their pregnancy, explain Inserm, CNRS and UGA in a press release accompanying the study.

Tobacco use during pregnancy has been shown to have many negative consequences for the health of mother and child, but "the mechanisms involved are still poorly understood".

We also know that the placenta, vulnerable to many chemical compounds, plays a crucial role in the development of the fetus.

In the study, the researchers found that the altered regions most often corresponded to areas that remotely control the activation or repression of genes.

In addition, some of them were located on genes known to have an important role in the development of the fetus.

Also, Johanna Lepeule, researcher at Inserm and who directed this work, hypothesizes that the epigenetic modifications observed in the placenta of smokers or ex-smokers “could partly explain the effects of smoking observed on the fetus and the subsequent health of the child ”.

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  • Pregnancy

  • Tobacco

  • Health

  • Cigarette