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The Trump administration's take on Tylenol and autism has led to confusion. It has put doctors who treat people who are pregnant or families with young children on the front lines of helping patients understand the evidence. NPR's Allison Aubrey reports.
ALLISON AUBREY, BYLINE: Dr. Nicole Baldwin is a pediatrician in Cincinnati, and when she was pregnant with her own child, she took a bad fall and was in pain.
NICOLE BALDWIN: And if I hadn't had Tylenol to take, I can't imagine the suffering I would have had for two months, you know, 'cause there's no other options. There are no other medications that these pregnant women can take.
AUBREY: After yesterday's announcement from President Trump telling pregnant women not to take it, the American Academy of Pediatrics issued a statement pointing to dangerous claims and misleading information. And the American College of Obstetrics and Gynecology (ph) has affirmed the safety and benefits of Tylenol during pregnancy. So what to make of President Trump's advice? There is no evidence that acetaminophen causes autism. Even the FDA acknowledged this in its notice to doctors after yesterday's announcement.
But the Trump administration has pointed to studies that have found a link between autism and Tylenol. However, a link doesn't mean much. It can be a coincidence or a fluke. I talked to Dr. Baldwin about this, and she brought up a great example - the link, what scientists call a correlation, between shark bites and ice cream. In the summertime, both increase. More people eat ice cream, and there are more shark bites. But does one cause the other? Of course not.
BALDWIN: And so if you can say, oh, yeah, I know buying ice cream doesn't cause you to get attacked by shark, then you could understand just because something is correlated at the same time, it doesn't mean that it's actually causing anything.
AUBREY: Scientists wrestle a lot with the difference between correlation and causation. Take Brian Lee. He's a professor of epidemiology and biostatistics at Drexel University. And a few years back, he collaborated with researchers in Sweden. In the first part of the study, they compared children who had been exposed to Tylenol - which is a trade name for the drug acetaminophen - with children who had not been exposed in the womb. And they did see a small statistical association linking Tylenol use to autism.
BRIAN LEE: We found that there was an association with increased risk of autism and ADHD. But autism is a very heritable condition, and association is not causation.
AUBREY: So he tried to drill down on this question by comparing siblings. Specifically, he and his colleagues looked at cases where one child had been exposed to acetaminophen during pregnancy and the other had not.
LEE: When we did the sibling analysis, the association completely disappeared. In other words, the association was not a causal one, and it was most likely due to other factors like genetics, infections, fevers, that sort of thing.
AUBREY: He says it's likely that a combination of factors are involved in causing autism, but acetaminophen probably isn't one of them. Lee says the kind of study that could put this issue to rest to more definitively show that this common medication is not an underlying cause of autism is unlikely to happen.
LEE: The gold standard for science is the randomized controlled trial, and you can't exactly do this with pregnant women. It's not really ethical to do that.
AUBREY: That would require asking participants during pregnancy to refrain from using the one medicine that has been shown to be safe to treat fever and pain. Tylenol was first introduced in the 1950s and has been used by millions of people for decades. Doctors around the globe say it's safe to use during pregnancy, and there is no evidence it causes autism in children.
Allison Aubrey, NPR News. Transcript provided by NPR, Copyright NPR.
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