Was it ever explained or was it the emotional roller coaster she kept having with her family that ultimately did it?
shareIts pretty obvious. Stress and anguish very often cause miscarriages, that's clearly what happened here.
I'm a civilian, I'm not a trout
Sadly miscarriages are not uncommon even today. I'm sure the stress of the secrecy and the physical exhaustion of the road trip added to it but she could have miscarried even if she had stayed at home and relaxed.
The real reason of course was that the writers painted themselves in a corner and didn't want to have to deal with the consequences of their twist.
For every lie I unlearn I learn something new - Ani Difranco