question about implantation

Posted By JAL on January 21, 1999 at 20:55:25:







I was reading in your archives and found several references to implantation and implantation bleeding.  I've never read much about this and am not sure how it works.  
Does everyone have implantation bleeding?  When does implantation happen (ie, how long after the egg is fertilized)?  
My mother said she had a regular period for 4 months when she was pregnant with me.  In one of your answers you said this is extremely rare and usually confused with implantation bleeding.  Would implantation bleeding happen over such a long time frame?  She says she had all the other symptoms of pregnancy and new she was pregnant at the time she was still having periods.  Is something like this hereditary?  As far as I know both of her earlier pregnancies were normal without bleeding and both babies were healthy.  
Thank you for your help.