Editor’s note: This article has been updated throughout.

The federal government’s announcement Monday linking pregnant people’s use of acetaminophen — the pain-relief drug sold under the brand name Tylenol — as a cause of autism could worsen their health and stigmatize one of the few treatments pregnant people have for reducing pain and fever, doctors warn.

“Not only is it false to say Tylenol causes autism, it’s really dangerous,” said Dr. Bhaskari Burra, an OBGYN in Asheville, North Carolina. “If people are hesitant to take Tylenol in pregnancy, it’s really concerning.” 

Health and Human Services Secretary Robert F. Kennedy Jr. on Monday announced that the Food and Drug Administration will issue a physician’s notice about the risk of acetaminophen use during pregnancy and begin the process of initiating a safety label change. Kennedy said this is based on studies suggesting a potential association between acetaminophen use during pregnancy and later diagnosis for ADHD and autism. The agency, which reports to HHS, will also launch a nationwide public service campaign about the change.

“We promise transparency as we uncover the potential causes and treatments, and we will notify the public regularly of our progress,” Kennedy said.

Trump, who attended Monday’s news conference, went further than Kennedy’s claims and warnings, and said pregnant people and their children should avoid Tylenol despite any potential pain and discomfort.

Researchers have been studying acetaminophen — the most common over-the-counter pain and fever medication for pregnant people — and its potential impact on fetal development for years. Though some work in the past has suggested a possible link between acetaminophen and neurodevelopmental disorders, more scholarship has refuted those connections. Last year, a study in the medical journal JAMA found there was no link between taking acetaminophen in pregnancy and childhood autism or intellectual disability. 

“The link between Tylenol in pregnancy and autism has not been shown. It is not borne out in the data,” Burra said. “We don’t have any data to show that Tylenol causes autism.”

The American College of Obstetricians and Gynecologists has long said that pregnant people can use acetaminophen safely in consultation with their doctor. The organization on Monday swiftly criticized the move linking them. 

Since drugs are not often tested on pregnant people, acetaminophen is one of the few pregnant people can safely use to relieve pain or fever — conditions that, if left untreated, can increase the risk of birth defects and premature delivery. Ibuprofen, another common pain reliever, has been associated with fetal heart problems and low amniotic fluid, which can also put pregnancies at risk.

“There’s benefits to controlling fever. There’s benefits to controlling pain,” said Dr. Zoe Taylor, a Washington-based family medicine physician who practices primary care, including a focus on addiction and pregnancy. “Not to mention all the other medications that I’m worried RFK Jr. is going to vilify as well, that have really significant benefits to patients and future children.”

During the Monday news conference, Kennedy said HHS recognizes that Tylenol is one of the only pain relief medications available for pregnant people, so the department will also encourage clinicians to exercise their best judgment on using acetaminophen for fevers and pain in pregnancy by prescribing the lowest effective dose for the shortest necessary duration. He also cautioned use of acetaminophen in young children, claiming there is evidence of liver toxicity. The medication is generally safe for children based on a doctor’s direction.

Trump’s thoughts were much more black and white: “Don’t take Tylenol. There’s no downside. Don’t take it. You’ll be uncomfortable, it won’t be as easy maybe. But don’t take it if you’re pregnant. Don’t take Tylenol,” the president said. “And don’t give it to the baby after the baby is born.”

Trump also promoted unproven connections between vaccines and autism. Kennedy said he would follow the president’s order and claimed many mothers with autistic children believe they were impacted by a vaccine injury.

“It will take time for an honest look at this topic by scientists, but I want to reassure the people in the autism community that we will be uncompromising and relentless in our search for answers,” Kennedy said.

The Monday announcements follow reporting from The Washington Post over the weekend that federal health officials intended to raise safety concerns about Tylenol use in early pregnancy and an increased risk of autism. The Wall Street Journal reported in early September that the federal government intended to link Tylenol use to autism, and that the details would be included in a Health and Human Services report that has yet to be released. On Monday, federal health officials also promoted a separate medication as a potential treatment despite limited research into it. The National Institutes of Health, a research division under HHS, also announced an initiative to examine the causes of autism.

The attention on linking autism to pregnancy is the latest in a series of efforts by Kennedy’s department to also discourage pregnant people from taking medications that scientific evidence and medical experts say improves health.

There is no single known cause of autism, a developmental disability that can impact how people think, move and communicate. The autism spectrum is broad, and rates of autism have increased in recent years in part because of better diagnoses. 

Dr. Mariana Montes, a Chicago-based obstetric anesthesiologist, said she worries that if pregnant people believe they cannot use acetaminophen, they will turn to riskier options for pain management: ibuprofen, which can harm a pregnancy, or opiates. Untreated pain also can put a pregnancy at risk.

“What they really want is they think if the mother suffers, the pregnancy will be the most healthy, and that is not true,” Montes said.

Earlier this summer, an advisory panel to the Food and Drug Administration suggested pregnant people should avoid a class of antidepressants called selective serotonin reuptake inhibitors — drugs including Prozac, Lexapro and Zoloft — claiming that taking them while pregnant could cause pregnancy loss, birth defects or autism. There is also no evidence linking antidepressant use to such health outcomes. 

Taylor said she meets with pregnant patients who are already very concerned about the health of their fetuses over their own wellbeing. She said medical professionals use the best science to advise patients about the risks and benefits of any medications they may be on at the start of their pregnancy or during, including SSRIs. 

“We do a lot to try to help patients understand that in many circumstances, staying on those medications is better for them and their baby. So I hate the idea that some of that work could be undone by misinformation,” she said. “There’s already plenty of misinformation about that on TikTok that we are dealing with, combating in visits every day — if it comes from the federal government, that’s even harder to explain.” 

In fact, both medications can actually keep pregnancies healthy. Patients who abruptly halt an antidepressant regimen can be at risk of serious self-harm; their babies too can be at greater risk of preterm birth, and of developing depression later in life.

Taylor said while it is important for the federal government and researchers to investigate the causes of autism, she is skeptical about the evidence that will be cited in this upcoming report. A recent systematic review of acetaminophen and autism only summarized prior studies and was not quantitative.

“I’m worried about what this says about the process that is happening. It’s not science and it is not expert review and guidelines anymore. It’s like, vibes,” she said. “That’s the thing that makes me worried — one article can come out that happens to get on one person’s desk and it makes a huge deal out of something. That’s not the way the process is supposed to work.”