Taking Tylenol or any generic acetaminophen during pregnancy is not clearly linked to autism or attention-deficit/hyperactivity disorder (ADHD) in children, according to a new review published in the BMJ on Sunday (November 9).

Researchers from the United Kingdom, Spain and Australia observed nine systematic reviews on the results of 40 studies examining usage of the pain medication by pregnant women and how it affected child neurodevelopment. The researchers warned against drawing a casual link between acetaminophen use during pregnancy and both autism and ADHD.

"Existing evidence does not clearly link maternal paracetamol use during pregnancy with autism or ADHD in offspring," the study's conclusion states.

The researchers also found that the nine reviews had critical flaws when they warned of potential association of "adverse neurodevelopmental outcomes" and acetaminophen usage during pregnancy, having not listed excluded studies and the reason for their conclusion, as well as inaccurate study designs and using non-standard tools to evaluate the risk of bias, the new review states.

Last month, Health and Human Services Secretary Robert F. Kennedy said there was not "sufficient" evidence that Tylenol causes autism one month after he stood alongside President Donald Trump he officially suggested that the over-the-counter could contribute to a higher risk for the condition.

“We’ve all said from the beginning that the causative association between Tylenol given in pregnancy … is not sufficient to say it definitely caused autism, but it is very suggestive,” Kennedy said, reiterating his warning that the medication should only be used by pregnant women when "absolutely necessary," on Wednesday (October 29) via the Hill.

“And so there should be a cautious approach to it, and that’s why our message to patients, to mothers, to people who are pregnant, the mothers of young children, is consult your physician, and we have asked physicians to minimize the use to one that’s absolutely necessary,” he added.

Trump and his administration officially suggested that Tylenol during pregnancy can contribute to a higher autism risk during a press conference on September 22. The president said the U.S. Food and Drug Administration would be notifying doctors that use of the medicine "can be associated" with an increased risk of autism, however, didn't offer medical evidence for the new FDA recommendation, the Associated Press reported at the time.

Kennedy linked circumcision and autism during a Cabinet meeting earlier this month and claimed anyone who opposed the theory was doing so based on hatred of the president.

“Anybody who takes the stuff during pregnancy unless they have to is, is irresponsible,” Kennedy said, while also claiming that anecdotes and statistics weren't proof via the Hill.

Republican Texas Attorney General Ken Paxton announced he's sued Johnson & Johnson and Kenvue, the makers of Tylenol, claiming they deceptively marketed the pain medication to pregnant women despite alleged links to autism and other disorders in a statement obtained by ABC News on October 28.

“Big Pharma betrayed America by profiting off of pain and pushing pills regardless of the risks," Paxton said. "These corporations lied for decades, knowingly endangering millions to line their pockets. ... By holding Big Pharma accountable for poisoning our people, we will help Make America Healthy Again.”

The lawsuit is the first from a state government against Tylenol since Trump made claims that the pain medication was linked to an increased risk of autism. Kenvue Inc., which is a spinoff of Johnson & Johnson, released a statement in response to Paxton's claims saying it is "deeply concerned by the perpetuation of misinformation on the safety of acetaminophen and the potential impact that could have on the health of American women and children."

"Acetaminophen is the safest pain reliever option for pregnant women as needed throughout their entire pregnancy. Without it, women face dangerous choices: suffer through conditions like fever that are potentially harmful to both mom and baby or use riskier alternatives. High fevers and pain are widely recognized as potential risks to a pregnancy if left untreated," the statement reads. "We will defend ourselves against these baseless claims and respond per the legal process. We stand firmly with the global medical community that acknowledges the safety of acetaminophen and believe we will continue to be successful in litigation as these claims lack legal merit and scientific support."