how can I politely tell my best friend she's hurting my feelings?!

My best friend has been by my side since we were 12! She lives out of state and I speak with her daily. My only frustration is that she unknowingly seems to compare my pregnancy with my first child to her friend "Megan" she made while in her new town that I don't even know.
 Having the same gender baby as her (girls), it's been non stop comparisons.. "yeah that's what happened to Megan, Megan went thru similar issues, you and Megan are on the same track..." blah blah blah 
At first it didn't bother me but now.. I get very easily frustrated and annoyed bc 1) every pregnancy is different and 2) I don't even know this girl and frankly I don't really care...
I'm mentioned before I don't really know her and I don't think she means in intentionally, but I'm getting frustrated bc it's now almost everyday comparisons and i want to tell her that i don't like it but I'm not sure how to do it politely and upsetting friendship boundaries... any suggestions? TIA