Maybe strange questions but.....

[Tigglettchic]

I was watching one of my many baby programmes the other day and a mother was having twins. She went into premature labour and had her first twin, however, before the second could be born (vaginally) her cervix closed up and it was another week until her second was born.

Q1 - is this just an american thing

Q2 - are they still twins??

Q3 how the hell do you explain that one??

It can happen, although is incredibly rare!
Yes, still twins, same as if one was born before midnight, and one after, don't need to share a birthday to be twins.
And absolutely no idea how you would explain that!