Low heartbeat small fetus

I went in for an ultrasound at 7 weeks.  The doctor said the heartbeat was low (around 80) and the fetus looked to be about 1 week too small.  He said the odds were 50/50 that the fetus would not survive.  Can anyone tell me whether they had any similar experiences at this stage and if there is anything that I can do to improve my odds?

[AnnieBrooke]

With my last pregnancy, at my 7-week ultrasound, one of the twins had a heart rate that the doctor thought was just borderline fast enough (at 105 bpm).  The fact that it was that low when he expected 120 (and the other twin was higher) was very worrying.  Ultimately it proved to be a correct indicator that something was wrong,   I'm sorry, but there is nothing you can do, it is entirely up to the embryo now.  It either has everything it needs to continue, or it does not and will fade.  Again, I'm sorry.

[alaysha]

At my 6 week ultrasound my daughter only had a heartrate of 95. From what I have heard that isn't that uncommon when the heart first starts beating and in early pregnancy its possible for the fetus to measure up to a week behind. My daughter would measure right on one week and then next she'd be behind and then the next she'd be a little less behind, etc, etc, etc. She's 1 1/2 now and healthy as a horse.