The OP has a medical appointment, so I'm surprised at your hostilityAnd the coworker has a medical issue as well that must be considered.
The OP is handling her own issues, the coworker is making her issues the OP's problem and ONLY the OP's, she not complaining when others eat at their desks which leads me to believe that this woman has less of an issue with the actual eating and more of a problem with the OP. Fruit leather and protein bars really don't have much of a smell, if she can't have those, what's next no coffee? tea? water? where does it end? and when? exactly how much does the OP need to concede to the co-worker who really seems to be hostile to the OP. I could see it if the OP were eating say a Big Mac and Fries or something similarly smelly but the things she is describing, really are not smelly at all.
Just because this lady is pregnant does not mean that her issues are all medically based ( or that they are not) nor does it confer more or less stature to them. It just means she needs to deal with them and not make them other people's issues.
If this were an instance of EVERYONE'S food bothering her I'd be more sympathetic..but, again, that's not the case. The best advice I have is to begin as you mean to go on - if you intend to give into every demand that every pregnant person makes on you with regard to what you eat, give in here. If not don't and let things take their course.