Can I Take Tylenol in the First Trimester?

About Tylenol in the first trimester if you get a cold or fever: What do I do this early (weeks 5-8)? Just live out the low fever or take Tylenol?
—TTC when toddler just brings home the germs!

In April, 2024 a new paper was released which uses a much better approach to the data to address this question. That paper establishes there is no relationship between Tylenol exposure and ADHD or autism in children. Please read the post in this updated data here.

This feels to me like the classic “Damned if you do, damned if you don’t.” Half the internet is going to tell you that if you take Tylenol once, your child will have behavioral problems forever. The other half will tell you that fever in the first trimester is super dangerous. Also, don’t take Advil! That’s worse! And so on.

Both the fever and Tylenol concerns are tremendously overblown.

Let’s start with Tylenol. The big concerns raised are around the possibility that taking it in pregnancy might be associated with an increase in the risk of behavioral problems or ADHD in children. I’ve written about this several times in the newsletter, including here and here. None of the evidence is ironclad, but as I say in those posts, when we think about extended and frequent use of Tylenol in pregnancy, reasonable people may differ in their choices, just given what the data says. However: even if you are on the cautious end of data interpretation, occasional use of Tylenol isn’t implicated.

On the topic of fever: While it is true that in some case-control studies, fever has been linked to birth defects, in better studies this doesn’t show up. A good example is this study, from Denmark, which included around 8,000 women and showed no link between first-trimester fever and birth defects. More work needs to be done on this. One note, though, is that data does show that any link between fever and birth defects even in case-control studies seems to be attenuated with use of medication for lower fever.

Where does this put you? Again, I think both sides of the coin are overblown. There are limited risks to letting the fever run and limited ones to taking Tylenol. I’d take the Tylenol, if only because dealing with a toddler while also having a fever is … the worst.