Acetaminophen (also sold under the brand name Tylenol) has a long history of safe use during pregnancy. The drug hasn't been well studied in pregnant women (few drugs have). But it has been widely used with few, if any, adverse effects. Healthcare providers consider acetaminophen to be the over-the-counter pain reliever and fever reducer of choice during pregnancy.
It's fine to take either regular or "extra strength" acetaminophen, but be careful not to take more than the amount recommended on the label. If you take too much, it can cause liver failure both in you and, later in pregnancy, in your baby as well.
Check with your healthcare provider before taking any multi-symptom remedies such as Tylenol Cold. These remedies contain a host of other medications, some of which may not be safe to take during pregnancy.