betas??

cessa

I keep seeing posts about Beta numbers.  I don't know mine and honestly, am not really even sure what they mean.  I don't remember ever knowing them with DS either.  Is this something that you check only due to previous complications TTC or a history of m/c?  

Hope I don't come across as insensitive or anything, just wondering why it seems so many people, aside from me, know their beta numbers....and wondering if I should.