Can baby survive if born at 20 weeks?

Don't think so. From week 24 they can be saved, but w20 is awfully early. As NICU care has improved over the last 40 years, viability has reduced to approximately 24 weeks, although rare survivors have been documented as early as 21 weeks.

The first thing survival will depend on is being in the right hospital for the birth - after that it depends entirely on the number of complications following birth and how well the baby pulls through each of them.