For those who have MC'd more than once...

Friends of ours have just told us via email that they have MC'd for the second time (we didn't know she was pregnant either time). They wanted everyone to know that all was not well, but didn't really feel like talking.

I know that we will see them sooner than later and I'm wondering what I might be able to do to help? Does anyone know where I can find information on MCing and why it might happen and why it would happen several times? I just want to give them a silver lining...

TIA