New research indicates brain development and brain functioning may be impaired in animals delivered via cesarean section.
The study comes as C-section rates are skyrocketing, with nearly one-third of all U.S. deliveries performed surgically.
A team from Yale University looked at the expression of a particular protein, called UCP2, in mice that were born vaginally and those born by C-section.
“We didn’t start this by asking that question," said Tamas Horvath, a researcher in the department of Neurobiology and Obstetrics at Yale University. "We weren’t interested in a C-section versus natural birth study.”
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He said it was just something they noticed while studying the protein’s effects on the brain – something he and his team have been doing for 16 years.
The research appears in this week's journal of the Public Library of Science.
The protein has been tied to the proper development of neurons and circuits in an area of the brain known as the hippocampus, the area responsible for both short- and long-term memory. It is believed the protein is involved in the metabolism of fat, which is one of the most critical components of breast milk.
Horvath said he and his team had been looking at how the expression of the gene – in other words, when the protein is turned on – affected the brain at different stages of mouse fetal and infant development. They noticed there was a big difference between those mice that had been naturally born versus those removed surgically.
They found the expression of the protein in the hippocampus of baby mice born vaginally was much greater than those born via C-section.
The researchers then tried to test what effect this protein had on juvenile and adult behavior. They found that those animals that lacked the protein were more anxious than those that had it. The animals moved slower and traveled only short distances.
“I don’t want to say that one way is better than the other,” Horvath said. “What is important is that they are different.”
And he said that difference is something researchers need to be aware of and look at in order to understand the consequences of that difference.
Horvath would now like to see if the difference he saw in mice is also found in different animals.
And he's hoping more general questions about elective C-sections will be asked.
"Many women now prefer C-sections. They can schedule at their own convenience, and that of their physician's," he said.
And it is partly this convenience but also an increase in the number of older women and overweight women that is contributing to the rise in cesarean births.
A California Watch investigation found that C-sections were more prevalent at for-profit hospitals than nonprofit hospitals, indicating there may be an economic incentive, as well.
But not everyone is convinced the results of this study should be included in the debate about elective C-section.
"I think it may be hard to extrapolate from mice to humans on this one," said Elliott Main, medical director for the California Maternal Quality Care Collaborative, a nonprofit designed to improve the care of maternal care. "But there are plenty of other good reasons to reduce C-sections."
However, while the research is still new and only suggestive, Horvath does think it has merit.
"These results reveal a potentially critical role of UCP2 in the proper development of brain circuits and related behaviors," Horvath said. "The increasing prevalence of C-sections driven by convenience rather than medical necessity may have a previously unsuspected lasting effect on brain development and function in humans as well."