What Causes Vaginal Spotting During Pregnancy?

hi i'm 28yrs old. married since 5yrs. i've been treated for hypothyrod since 2005. I was pregnent inthe year Dec 2006 but on jan i had little spoting and Dr said its ok for some people it happens.....But, on feb after my scan my Dr told me due to Genie mismatch the fetus groth stoped And Dr told to abort it after thati never concieved.........

my in laws are Pressurizing me i'm help less pls healp me