Unlike news reports of the 2000s that erroneously linked childhood vaccinations to autism, the threat of terbutaline sulfate to fetal brains is backed by scores of peer-reviewed studies and decades of research.
The MMR (Measles, Mumps, Rubella) vaccination scare stemmed from a now-debunked article that was immediately met with skepticism by the scientific community. Researchers weren’t able to replicate the findings.
The article published in 1998 in The Lancet was based on a study of 12 children. Led by Dr. Andrew Wakefield, the authors reported that the parents of 8 of the 12 children associated loss of skills, including language, with timing of the MMR vaccine.
But other researchers couldn’t verify the results.
“Large-scale studies, smaller studies, retrospective studies, prospective studies, and case-control studies … all come to the same conclusion: there is no connection between vaccines and autism,” Dr. Andrea Darby-Stewart of Scottsdale Healthcare, said in an article published in 2010 in the American Family Physician.
“The only outlier is Dr. Wakefield’s study, which suggests this possible link,” she continued.
After Great Britain’s General Medical Council in 2010 issued a scathing report of Wakefield, lead investigator in the study, The Lancet retracted the article. The council reported that subjects of Wakefield’s study had been carefully selected to skew the results, and found that Wakefield had acted unethically.
Early animal research
A link between terbutaline and autism emerged from animal research in the 1980s and 1990s.
In 2011, the California Twins Study found that, contrary to common belief, the intrauterine environment accounted for a much higher percentage of autism cases than previously thought.
Also that year, research showed a higher risk for children born to mothers treated for preterm labor with terbutaline than for mothers treated for preterm labor with any other drug in that class.
Dr. Theodore “Ted” Slotkin, who conducts research on brain development at Duke University, says his initial animal studies focused on how cells in the developing brain responded to terbutaline. Coincidentally, he said, other studies emerged indicating that weeks-long use of terbutaline could alter the fate of the developing brain.
Terbutaline is a stimulant that works much the same way as adrenaline. The FDA approved terbutaline for asthma in 1974, and in the 1990s it became the most widely used drug to calm the contractions of premature labor. However, pharmaceutical companies never tested terbutaline for that purpose.
“Terbutaline is a drug that is commonly misused in preterm labor,” Slotkin told a panel of scientists in 2007 at a workshop called specifically to address increasing rates of ASD. “It inhibits uterine contractions, but it is effective only for about 48 to 72 hours in doing that.”
“As predicted, terbutaline produces permanent changes in responsiveness” by overstimulating nerves in the developing fetal brain, Slotkin says.
Autism begins during gestation
Preterm labor in mothers carrying twins seems to coincide with critical points of fetal development. Terbutaline crosses the placenta and saturates the fetal nervous system during a specific stage of growth in the fetal brain. Terbutaline given at the wrong time can alter the fate of nerve cells in the fetal brain.
Furthermore, studies during the last decade reveal autism as a disorder that occurs during gestation. In other words, the course of autism is set at the time of birth. Scientists examining the autopsy results of autistic patients say that characteristic markers seen in the brains of autistic patients develop only during fetal development.
- CMAJ. Lancet retracts 12-year-old article linking autism to MMR vaccines. CMAJ [Internet]. 2010Mar.9. Available from: http://www.cmaj.ca/content/182/4/E199.full.pdf
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- Dachs R, Darby-Stewart A, Graber MA. Autism and Childhood Vaccinations: Debunking the Myth. Am Fam Physician. American Academy of Family Physicians Publications Division 11400 Tomahawk Creek Parkway Leawood, KS 66211-2672 800-274-2237; 2010;82(6):586–92.
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