Acetaminophen, the active ingredient in Tylenol and Excedrin, is thought to be one of the safest painkillers there is. It has had a good record of safety for many years. Health professionals stress that this study alone, while worth paying attention to, is not enough to cause acetaminophen to be banned outright. It’s worth reiterating what you already know from your basic science education; an “association” (or correlation) does not prove cause-and-effect. Even the authors of the study stress that further study is warranted before any drastic action is taken.
Acetaminophen has some very important positive actions in addition to pain suppression. Most importantly, it can lower a fever. Until more is known about acetaminophen and fetal development, doctors suggest that pregnant women simply reduce their acetaminophen use to a minimum; use it for lowering a fever, but not for minor aches and pains.