It may already be controlled for, but if not, the increased Acetaminophen intake could be from narcotic painkillers, which are often combined with Acetaminophen in prescription preparations to help prevent abuse. The same people seeking and using those around birth may later seek to get an ADHD diagnosis for a child for access to amphetamines, as narcotics use and amphetamine use are highly correlated together.
> the increased Acetaminophen intake could be from narcotic painkillers, which are often combined with Acetaminophen in prescription preparations to help prevent abuse
This is just evil. Congratulations, now we have opiate addicts with needlessly destroyed livers as well...
I believe it allowed them to illicitly claim lower addictiveness in their clinical studies, since they could throw out people who removed the Acetaminophen with a filter (as is common in real abuse), as people not taking the prescribed combination (or the techniques for removing it only got broad use after it was already approved).