Myth 31: All Anesthetics During Birth Harm Babies’ Brains


No less a revered medical institution than the Mayo Clinic, the saviors of severely medically challenged children nationwide, have studied and declared that anesthetics used during cesarean births do not cause children to have brain problems.

Mayo Clinic researchers have found that children exposed to anesthesia during Cesarean section are not at any higher risk for learning disabilities later in life than children not delivered by C-section. These findings are reported in the current issue of the journal Anesthesiology.

“We found that the incidence of learning disabilities was equal between children who were delivered vaginally and those who were delivered via C-section but with general anesthesia,” says Juraj Sprung, M.D., Ph.D., a Mayo Clinic anesthesiologist who led the study. “It’s reassuring that the anesthetics required for Cesarean delivery do not appear to cause long-term brain problems.”

The study was conducted with data from the Rochester Epidemiology Project. Researchers analyzed the medical records of 5,320 children born between 1976 and 1982 to mothers living in Olmsted County. They compared birth records with scholastic achievement and IQ tests administered to the children later in life as part of their schooling.

The study builds on a previous project, reported in March, which found that children exposed to a single dose of anesthesia during the first three years of life had no increased risk for learning disabilities, but those exposed multiple times had an almost doubled risk for later identification of learning disabilities.

Prolonged exposure to anesthetics has been shown to cause brain abnormalities in young animals, which was the impetus behind these two studies. Scientists think that the brains of young animals and humans are more vulnerable to a variety of problems because they are undergoing rapid growth. The brain is forming vital connections between cells during this time.

Not only did the researchers find that the use of anesthesia during delivery was not harmful to the baby, they found that babies delivered by Cesarean using an epidural anesthetic (which numbs only the lower region of the body and does not involve the mother going to sleep) had a substantially reduced risk for learning disabilities later in life. “The risk was reduced by about 40 percent compared to children delivered vaginally and those delivered via Cesarean section but with general anesthesia,” says Dr. Sprung.

Study co-author and Mayo Clinic anesthesiologist Randall Flick, M.D., cautions that because this study is preliminary, changes to medical practice should not be considered at this point. “What we’ve found is an association between two things,” says Dr. Flick. “One is the way a child was delivered, either vaginally or under regional or general anesthesia. The other is a difference in the incidence of learning disabilities as the child attended school. It’s important to recognize there may be many other factors that impact learning disabilities.”

The team is investigating whether use of an epidural on a mother during natural labor has similar effects on the incidence of learning disabilities in children as a C-section with an epidural.

Dr. Flick says the research team also is working with the U.S. Food and Drug Administration (FDA) on a related study that looks more closely at young children with specific medical conditions who have been exposed to anesthesia and compares them to children with similar medical conditions who were not exposed to anesthesia. The study is part of a national SAFEKIDS Initiative that the FDA is undertaking with several academic and clinical institutions to study the effects of anesthetics and sedatives on brain development in infants and young children.

Funding for this study was provided in part by the Mayo Clinic Center for Translational Science Activities (CTSA). The Mayo Clinic CTSA is part of a national consortium working to improve how biomedical research is conducted across the nation. The consortium, funded through Clinical and Translational Science Awards, shares a common vision to accelerate the time it takes for laboratory discoveries to become treatments for patients and to engage communities in clinical and translational science. It is also fulfilling the critical need to train the next generation of clinical researchers. The CTSA initiative is led by the National Center for Research Resources at the National Institutes of Health.

Additional co-authors include Robert Wilder, M.D., Ph.D.; Slavica Katusic, M.D.; Tasha Pike; Mariella Dingli, M.D.; Darrell Schroeder; William Barbaresi, M.D.; Andrew Hanson; and David Warner, M.D. Another co-author is Stephen Gleich, M.D., of the Primary Children’s Medical Center, Salt Lake City.

6 Responses

  1. I’d like to read the entire article, and not just the abstract. I wonder if they controlled for enough stuff in this study. I was born in another state during the time period of this study, and my mom was knocked out during a routine vaginal birth; I assume I was dragged out by the head with forceps. Obviously, I have no learning disability — but just because a woman gave birth vaginally does not mean she did not have general anesthesia nor regional anesthesia. Was this controlled for? It appears that all vaginal births were lumped into one group, regardless of whether or not a woman had drugs either for pain (such as an epidural, IV or IM or SQ narcotics or other drugs), or to speed up her labor (pitocin); it also is not noted in the abstract whether there were any forceps or vacuum (if applicable at the time) births; nor was the neonates’ condition noted.

    Some women may have gotten general anesthesia, and were “under” a lot longer with their babies inside of them, during a vaginal birth than during a C-section — a typical C-section takes an hour, but the actual time from giving drugs to getting the baby out is in the neighborhood of 5-15 minutes — quicker if an emergency, slower if not. I recently read a nurse’s first experience with attending a C-section with general anesthesia, and she said the doctors worked in double-quick time, because they wanted the baby out as quickly as possible, so it wouldn’t have negative effects from the drugs given to the mother.

    I find it interesting that “drugs don’t harm the baby” yet somehow babies whose mothers were given regional anesthesia had fewer LDs than mothers given general anesthesia. It would seem, then, that general anesthesia was more harmful to babies than regional anesthesia. Were there *any* mothers not given *any* drugs? These should have been the control, not just “vaginal birth” which can come with a plethora of drugs and other interventions.

  2. […] first read about the study on “Mommy Myth Busters,” and they look at this from another angle, and include more information, including that […]

  3. This is a very flawed conclusion if you’re only relying on this data. First you have to realize that this only compares the rates of cognitive damage so severe that it would be classified as a learning disability. But that means that a kid born to parents with PhD’s from Harvard who only manages to graduate high school wouldn’t be counted as being “harmed” because his intellect would be in the range considered to be a normal human being. Of course it’s unlikely that a short burst of anesthesia would lead to damage so severe as to cause severe cognitive damage.
    But as the study also shows the lower exposure via an epidural C-section has less risk than general anesthesia-which is very clearly showing that the anesthesia is indeed causing harm. And it doesn’t appear that they broke out epidural vaginal delivery versus non-epidural vaginal delivery, which may explain why vaginal delivery has similar rates of severe cognitive impairment as general anesthetic C-section. In a vaginal delivery with epidural the baby would be exposed to the epidural for a much longer period of time-hours and hours. Whereas in a C-section done under epidural the baby is out in about half an hour.
    I think all in all this mostly just shows that the less exposure a baby gets to anesthetic drugs the better-because the C-sections done under epidural have a pretty substantial 40% risk reduction versus general. That is, general anesthesia leads to twice as many cases of impairment severe enough to qualify as a learning disability.
    And this is entirely ignoring the fact that “harm” shouldn’t be merely limited to having severe enough impairment to be considered as having a learning disability! Making kids that would have been smart normal or slightly stupid but not enough to qualify as a disability isn’t exactly a great thing either.

    • Hey Tek…..

      Just because someone didn’t get a Ph.D or didn’t go to college doesn’t mean they’re not smart, and it certainly doesn’t mean they’re mentally damaged. The smartest folks I know didn’t go to college. Sure, they give you a blank stare when you whup out something about Occam’s Razor, but the understand the concept intrinsically. The flip side of this is the people I know who did get bachelors, masters, ect, who I wouldn’t trust to take out my garbage. Going to school means you’re EDUCATED, not smart.

      And near as I can figure, anethesia ain’t real good for any humans… babies, children or adults… that’s why it’s only administered when ABSOLUTELY NECESSARY.

  4. So just about the only thing this proves is that the exposure to anesthetic in an epidural C-section is very low. But in fact this study mostly seems to show that general anesthesia *does* harm babies because otherwise there should be no difference between a C-section done under general and those done under epidural.
    And from there you can extrapolate that vaginal deliveries done under general anesthesia likely also have higher rates (and were lumped into the vaginal category). Vaginal deliveries with epidural most likely also have some effect too depending on length of labor, since in prolonged exposure to epidurals the babies usually come out in somewhat of a stupor meaning that the drugs have managed to cross into the baby.
    It is thus grossly incorrect to claim that anesthetics do not harm babies brains using this study because this study mostly shows the complete opposite-that there is almost double the risk of learning disabilities with general versus epidural. It’s preposterous to instead insist that general anesthesia be the baseline and that the epidural is “reducing” risk. How can there be no increased harm from general anesthesia if not using it results in 40% of the risk going away immediately?

  5. “It is thus grossly incorrect to claim that anesthetics do not harm babies brains using this study because this study mostly shows the complete opposite-that there is almost double the risk of learning disabilities with general versus epidural. It’s preposterous to instead insist that general anesthesia be the baseline and that the epidural is “reducing” risk. How can there be no increased harm from general anesthesia if not using it results in 40% of the risk going away immediately?”

    What if epidurals are actually protective? But general anesthesia makes no difference?

    As the doc in the study said, wait till more studies are done to sort this out.

    Correlation does not mean causation.

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