If it only has Acetaminophen among the active ingredients, then I wouldn't worry. Acetaminophen definitely is okay to take in "normal" sorts of doses. But there are several types of Tylenol cold syrup, so you have to read the label carefully to see which one you get.
For instance, take Tylenol Cold Head Congestion NIghttime. Pregnancy is not listed as a definite contraindication on their website. And the main active ingredient is Acetaminophen. But another active ingredient is Phenylephrine HCl, which has been teratogenic (causes birth defects) in some animal studies. This may be too low a dose to be harmful, but it also may not be worth the risk. Another ingredient that came out badly in animal studies: Dextromethorphan HBr. Again, probably not a risk in the dosage presented, but you can't be sure.
Acetaminophen on its own is probably just as effective, and safe enough in normal dosage amounts. Tylenol Sore Throat Daytime looks okay, if you can find it.