No, she has no history of miscarriage so far as I know. She is almost 22, and has been with the father for 2.5 years now. So yes, she is young, but she isn't extremley young. I think she may have been worried about what they would think. But I have told her, I was younger, and my situation was worse, and yes, my parents were a little bit dissapointed at first, but they love my son to death.
My parents are moving in a month, so my sister said she didn't want to stress them out. But really my sister is still pretty much unprepared right now, and in a month my parents will be over 4 hours away, so it will be harder to help.
My sister said she has known since May, she should have told them this summer. That's my opinion, although it's too late now, lol. There's gonna be a baby in 2 months!