It very much is still your wife's body - what other sentient entity is available for consultation?
I also am not sure if she is seeking professional medical advice - 'baby aspirin' is not a blood pressure medication, full stop. If this is based on non-medical doctor advice, please do consult a fully-qualified obstetrician.
Edit, just because this is very worrying to me, for later viewers, aspirin is an NSAID and its use should be weighed similar to that of other NSAIDs in the context of pregnancy. Consider this web page:
https://www.fda.gov/safety/medical-product-safety-informatio...