Birth by cesarean section may alter babies DNA

A cesarean section is when the mothers abdomen and uterus are surgically opened to deliver the baby. This can be due to a number of factors including placental separation from the uterine wall, the position of the baby, or if the baby is in distress.  Cesareans are gradually increasing over time, in the US 2005 the rate was at a staggering 29% of all births and in China the rate is closing on 50%.

The cesarean is not without risk. The risk to the mother are post labor pain and discomfort as well as the risk for bleeding and infection that is present in all types of surgeries. It is known that babies delivered by cesarean has a higher risk of  Type I diabetes , the reason why this is the case is unknown but we might be closer to understanding it.

Cesarean sections Alter DNA

In a study led by Professor Tomas Ekström at Karolinska institutet in Sweden an explination to the why might be one step closer.

Epigenetics is the way in which the environment affects DNA leading to the information in it being expressed differently. It might seem like a complicated concept but the gist of it is that the environment don’t change the DNA but can influence what type of information it expresses.  An example of epigenetics would be that sun exposure leads to an increased production of melanin which turns your skin darker.

So in the case of the babies delivered by cesarean the researchers found methylation at a higher degree in the stem cells of the newborn babies as compared to babies delivered vaginally. This methylation is one of the mechanisms of epigenetic changes. When a methyl group binds to a site on the DNA it can stop the expression of a gene located in that site.

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Artist rendition of DNA methylation

 

 

 

 

 

 

 

 

 

 

 

 

When the researchers did a detailed study in 12 of the babies they found statistically significant differences in methylation in almost 350 regions of the DNA. Many of these regions are known to influence the immune system.

The epigenetic changes can be either permanent or temporary and the researchers are unsure whether the observed changes will last. There are certain to be follow up studies on this area, especially due to the increase in cesareans worldwide.

 

 image credit: Christoph Bock via Wikimedia, license