"the Church decided to discipline her"

She needs to leave that group and find a true body of believers, though that is most likely not possible today. What she did may be questionable but is not sin. Those who wish to discipline her and cause her stress are the ones who sin. Do they wish her to bring forth a child in doubt and regret? Let her bring forth her child in love and joy.

We cannot change what is done but we can grow from it. Even if this was a sin, it is not a sin unto death. If they pray, she shall be forgiven.

1 John 5:16

James 5:15 And the prayer of faith shall save the sick, and the Lord shall raise him up; and if he have committed sins, they shall be forgiven him.