I'm glad you trust the CDC and the study that was done by glaxo-smith-kline, who happens to make vaccines. Of course they say it's safe to use in pregnant women. The FDA consider TDaP a Class C drug: Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans
So maybe YOU should do a little research. Additionally, if the other girl had a pre-conception visit, she would know she'd had one in the last 5 years and would have no reason to worry at all.
Furthermore, the bigger concern in pregnant women is rubella, which should definitely be tittered at a preconception visit. Do your research: even the CDC strongly advises against MMR during pregnancy.