“The dose makes the poison,” as they say. So just how many days of consecutive Tylenol consumption are too many for a pregnant mother? That’s not clear. The general principle seems to be that the more Tylenol a woman takes, and especially the longer she takes it, the higher the risk for her baby or babies of developing autism or ADHD. The 2016 Spanish study researchers wrote that “These [autism and ADHD] associations seem to be dependent on the frequency of exposure.” And, as University of Texas Southwestern OB/GYN Dr. Robyn Horsager-Boehrer pointed out, none of the studies reviewed in the 2018 meta-analysis found an increased risk of ADHD when mothers used Tylenol for a week or less. //

While not a research study, in 2021, the journal Nature Reviews Endocrinology published a consensus statement* signed by more than 90 researchers, scientists, and clinicians, cautioning pregnant women to limit their use of Tylenol. The statement, which listed more than 160 references as evidence, read:

“We recognize that limited medical alternatives exist to treat pain and fever; however, we believe the combined weight of animal and human scientific evidence is strong enough for pregnant women to be cautioned by health professionals against its indiscriminate use, both as a single ingredient and in combination with other medications….Packaging should include warning labels including these recommendations.”

The statement signers recommend pregnant women take Tylenol “cautiously at the lowest effective dose for the shortest possible time” //

Differentiating correlation from causation

A 2017 position statement of the Society for Maternal Fetal Medicine, which issues practice guidelines for high-risk pregnancy specialists, called the research thus far “inconclusive.” While it’s true that research to date does not definitively establish causation, meaning that it doesn’t spell out ‘this amount of Tylenol use can definitely cause autism or ADHD in offspring,’ those raising the alarm point out that pregnant women deserve to know about the possibility of a connection because it may impact their decision to take Tylenol or not.

Is Tylenol during pregnancy better than other pain medications?

The USA Today story quoted Dr. Andrea Edlow, an OB/GYN and obstetric research director at Massachusetts General Hospital, noting that whereas she believes the potential Tylenol-neurodevelopmental disorders connection is “a nuanced area,” the common pain relief alternatives to Tylenol are already known to be unequivocally problematic for pregnant women and/or their preborn children. As Dr. Edlow points out, “Ibuprofen is clearly associated with developmental risk and maternal opioid use is also associated with maternal, fetal and neonatal risks.”