With respect, your question is not entirely relevant.  I merely pointed out an example of a substance which may safely be ingested by most people except pregnant women: unsafe for pregnant women but not unsafe for everyone.  The fact that it is the product of an experiment was included merely to put the fact in a laboratory context.

It is unsafe for women in the third trimester of pregnancy to ingest aspirin.  I doubt any of the women whose children’s birth defects led to this discovery were exposed to aspirin by any route other than oral.  Thus, I cannot speak to other routes, but again this is of limited relevance.  Aspirin, which could be present as a powder for authentic sample or mixed melting point purposes, could become airborne during operations. 

While the experiments in question would intend to preclude exposure, students often behave in such a way as to circumvent normal precautions.  For instance, one person spills a solution of aspirin on a bench top.  Another student puts a writing implement on this bench top and, later, into their mouth.  Many students find the habit of putting writing implements in their mouths very difficult to break during lab, even after repeated warnings.  If you feel that such an occurrence is unlikely, consider how the sweetness of most artificial sweeteners was discovered.  (Admittedly, that was cigarettes, but the principle applies, particularly considering that these discoverers were professional chemists who should have known better.)  Also admittedly, this would never be a safe practice, but unsafe practices are what lead to accidents and, like it or not, humans will have accidents.  The difference is the degree of severity of the accident, which for the fetus can be catastrophic.

BR

Do you mean that it is not safe for a pregnant woman to ingest aspirin or,  that it is unsafe for the pw to be in the presence of aspirin or chemicals reacted to make aspirin?  I would expect that any procedures designed for the aspirin-making experiment would eliminate ingestion,  as well as skin absorption and inhalation,  as routes of exposure.

RH