Twins with low heart rates

My wife is 35. Two weeks ago we found out she was having twins (fraternal.) They were approx. 61/2 weeks. Baby A had a very strong heart rate of 125bpm but Baby B had a heart rate of 79bpm. When we went in last week for another ultra sound Baby A had no heart beat and Baby B's heart rate had dropped to 72bpm. My wife was devistated! Why would the strong heart rate have disappeared? My sister in-law told me that her best friend had the same thing happen at 7 weeks and then at 8 weeks an ultrasound showed the heart beating again. Is this possible? Her best friend now has one year old twins. I am really worried that the heart rate of Baby B will continue to drop but have a sliver of hope that we might see two heart beats again when we go back in for the next ultrasound. What are the chances of that happening?

[kellym]

I am soo sorry. I have been reading a ton about the low fetal hr because I was 6weeks last week w/a FHR of 89. So, I'm just as scared. I hope they scheduled you for a repeat ultrasound. Although it seems grim, hopefully you will find yourself a happy ending.

[chiromom]

I was pregnant with twins.  I don't have the exact rates, but was told at an 8 week US that Baby A had a strong heart rate, and Baby B had a "variable" heart rate.  At 10 weeks, I started spotting, had an US, no heart beat for either.  I had a D&C Sept 1st.  There is nothing you can do, just wait and see.  Anything is possible, but as for probable, unlikely.  

[dsmommy]

I'm sorry that things are so unknown right now.  Sounds like she is about as far along as i am w/ twins and i'm scared everyday that something will happen to one or both.  I really hope you have another appt. soon and that it eases your fears!  Keep us posted....i will say a prayer for you.

[stephie4]

That's so sad.  How worried you must be.  So sorry you are going through this.

And here I am, waiting to see a hb, thinking once i see that, i'm free and clear.  
I hope they just didn't see the hb, and its still there like your sister-in-law's best friend.

I really hope you have a happy outcome, please keep us posted. when is the next us?