OBs Are Real Tired Of Studies Saying Tylenol Is Unsafe During Pregnancy

To be pregnant is to Google everything — can I eat this brie? What about my usual green tea? How much Tylenol is safe? But if you scroll too long on that last search inquiry, you can see some worrying results. Every so often, another new study comes out warning expectant parents that acetaminophen use during pregnancy might cause neurological issues for young kids, as Romper previously reported, from sleep trouble to attention difficulties. The newest study on the block says there is an association between taking the drug in the second and third trimester, and children having poorer early language development (specifically, smaller vocabularies and speaking in shorter sentences). And honestly, OB-GYNs are really tired of articles like these scaring their patients.

“I’m not saying studies shouldn’t be done, but I think sometimes these are harmful. We’re scaring people unnecessarily,” says Dr. Jeffrey Kuller, M.D., maternal-fetal medicine specialist and professor of obstetrics and gynecology at Duke Health. He talks about this body of research, the one investigating whether Tylenol causes neurobehavioral issues, like a persistent fly at a picnic. “It’s doesn’t seem to want to go away.”

“Within the last 20 years, and probably increasingly in the last 10 or so, there have been more and more studies coming out looking at neurodevelopmental outcomes and Tylenol use. And then this looks like an even more granular question [about] language development and Tylenol use,” says Dr. Barbara Wilkinson, M.D., M.A., OB-GYN at Brigham and Women’s Hospital. She seconds Kuller’s assessment of the study: it’s not changing her mind, or that of any OBs she knows. They all believe Tylenol to be safe to take in pregnancy.

The American College of Obstetricians and Gynecologists (ACOG) released a statement about this body of research in 2021, stating, “neurodevelopmental disorders, in particular, are multifactorial and very difficult to associate with a singular cause. The brain does not stop developing until at least 15 months of age, which leaves room for children to be exposed to a number of factors that could potentially lead to these issues…patients should not be frightened away from the many benefits of acetaminophen.” Their position has also been endorsed by the Society for Maternal-Fetal Medicine (SMFM), Kuller says, where he serves as chairman of the publications committee.

OK, but what did the study say, exactly?

The latest study examining Tylenol use in pregnancy, published in December 2023, asserts that “higher prenatal acetaminophen use during pregnancy may be associated with poorer early language development.” Researchers arrived at that conclusion after following 532 children from birth to around 36 months of age, asking parents to report the number of times they took acetaminophen six times throughout their pregnancy and giving the children language development assessments as they grew.

Both Kuller and Wilkinson say the study has its limitations though, and should not make anyone feel like they can’t safely take Tylenol while pregnant. But it can be hard to tell that when you’re just a regular person reading a headline.

“[The study] was relatively small. It looks like it was a largely white, non-Hispanic, well-educated, high-income cohort, which certainly doesn’t match the pregnant population in the United States at large,” Wilkinson says. She highlights that the children who displayed decreased vocabulary size knew between 0.58 and 1.8 fewer words than their peers. For most families, that word or two will not a difference make.

Many of the studies investigating Tylenol use and neurobehavioral outcomes have “significant limitations,” Wilkinson adds. “The Society for Maternal-Fetal Medicine came out in 2017 and said that, based on the literature that's available, they don’t see a causal association between Tylenol use and neurobehavioral issues. Overwhelmingly the data we have is quite reassuring,” Wilkinson says.

What OB-GYNs want pregnant people to know about medication use in pregnancy

Tylenol is safe to take while pregnant.

ACOG and the SMFM both recommend that, if you’re pregnant, you take the lowest dose of Tylenol needed to manage your symptoms, for the shortest amount of time possible. (This is generally their rule of thumb for taking any medication during pregnancy, experts say.) ACOG and OBs are generally “not buying it” that acetaminophen is causing neurobehavioral challenges for young kids, Kuller says.

“Tylenol has been studied for a very long time. The large body of literature on Tylenol is overall very reassuring,” Wilkinson says. “There are very large trials — I have one in front of me right now that was published in 2010, that looked at over 11,000 children in a case group and over 4,000 children in a control group, trying to assess for any risk of congenital anomalies, and didn’t identify any significant risk with Tylenol use,” Wilkinson says.

“This is clearly the safest pain reliever that we have in pregnancy,” Kuller adds.

We don’t know what effects unmanaged pain and inflammation can have on a fetus.

Skipping Tylenol while you’re pregnant seems like the easiest way to avoid any risk at all. However, unmanaged pain and inflammation — which Tylenol is the first line of defense against in pregnancy — could also be associated with fetal harm. In this study’s limitations section, it points out that “inflammation is commonly associated with pain as well as infections. Both inflammation and infections during pregnancy have been repeatedly linked to Autism Spectrum Disorder (ASD), a condition in which language is often impaired.”

“You have someone who’s suffering from migraine or a pubic symphysis separation or fever, and there may be direct consequences of that condition,” says Wilkinson. “Fevers in pregnancy have consequences. An untreated very high fever is definitely associated with congenital anomalies. So there are consequences of not taking Tylenol.”

There are also less direct consequences of not treating pain in pregnancy, Wilkinson says. If someone has a terrible migraine that changes their diet, exercise, or sleep, or causes missed work and wages (and therefore stress), “that has significant effects on that pregnant person and on that pregnancy as well.”

It is not your fault — or really even in your control — if your child has developmental delays.

Obviously, the idea that a medication you took may have caused your child’s speech delay, or any kind of issue for them, is a major blow to any parent. It comes up in conversations about taking SSRIs while pregnant often, Kuller says, and discourages parents-to-be from using medications they need. Both doctors urge patients to ask their providers questions about what they see in the news and online before taking any health info to heart.

“I get nervous that when pregnant people see these headlines, it makes them feel like they have control over every outcome of pregnancy. And fundamentally that’s just not how pregnancy works. Most of the things that we worry about happening in pregnancy are multifactorial — they come down to a lot of different things that are happening in the interplay of genetics and life and pregnancy and the neonatal period after birth,” Wilkinson says. “I worry about pregnant people having a child down the line who has any kind of health consequence, and thinking that they did this to their child. That’s just not fair.”

Ultimately, studies about how Tylenol affects fetuses are going to continue. But if you’re reading about them, don’t forget that your baby isn’t the only one whose health matters, Wilkinson says.

“These studies are really framing fetal well-being, which is incredibly important of course. And every pregnant person is going to be incredibly focused on fetal well-being and the life of their future child. But there’s a pregnant person at the center of this too. We can’t forget that when we dig through this data and think about what it means when pregnant people read about these studies.”

Studies referenced:

Woodbury, M. L., Cintora, P., Ng, S., Hadley, P. A., & Schantz, S. L. (2023, December 11). Examining the relationship of acetaminophen use during pregnancy with early language development in children. Pediatric Research. https://doi.org/10.1038/s41390-023-02924-4

Gevezova, M., Sarafian, V., Anderson, G., & Maes, M. (2020, November 13). Inflammation and Mitochondrial Dysfunction in Autism Spectrum Disorder. CNS & Neurological Disorders - Drug Targets, 19(5), 320–333. https://doi.org/10.2174/1871527319666200628015039

Experts:

Dr. Barbara Wilkinson, M.D., M.A., OB-GYN at Brigham and Women’s Hospital

Dr. Jeffrey Kuller, M.D., maternal-fetal medicine specialist and professor of obstetrics and gynecology at Duke Health