Missing Fetus in Sac at 12 Weeks: What Could It Mean?

Question
Hi Doctor,  I am a little more than 12 weeks pregnant and I just went in for
my second OBGYN appointment today.  I had gone in at 8 weeks, got my first
ultrasound, heard the heartbeat and saw the fetus in the sac.  All looked
good and measured normal.  At my appointment today, we didn't hear a
heartbeat.  The doctor did an ultrasound in the office, both on the belly and
then vaginally.  There was no fetus in the sac to be found!  Nothing.  Empty.  
This is my third pregnancy and I am 38 years old.  I am so confused.  How
could this be?  I have had some slight discharge, maybe five times total in
these three months - only one of those times was there any red blood - but
just a little.  The doctor determined today that I did have a polyp that was
close to the cervix that probably burst when having a bowel movement, but
that my cervix was tight.  What could be happening?  The doctor instructed
me to make an appointment for another ultrasound at the hospital.  What
could be happening?

Answer
Dear Catherine

It seems that u had an abortion. U already had 3 attacks of bleeding and any 1 of them could have ended in abortion without notice. This happens especially with chromosomally abnormal babies.

If a repeat scan after 1 week should empty uterine cavity, then the diagnosis is confirmed.