Yes it did appear she had cancer and possibly had just been going through chemo or radition thearpy... Why would Juliet want to impregnate her sister if she is going through that... Just to prove that she could do it? I know there was an issue between Juliet and the ex about ethics

__________________
Please don't give up, Des. Because all we really need to survive is one person who truly loves us. And you have her. I will wait for
you. Always. I love you, Pen

DESMOND: I love you, Penny. I've always loved you. I'm so sorry. I love you!
PENNY: I love you too.
DESMOND: I don't know where I am, but--
PENNY: I'll find you, Des--
DESMOND: --I promise--
PENNY: --no matter what--
DESMOND: --I'll come back to you--
PENNY: --I won't give up--
BOTH: I promise. I love you.