It is the amount of time a fetus needs to develop the organs and mechanisms needed to deal with the challenges of living outside the womb. (aboutkidshealth.ca)
Beyond that until the late second trimester, a fetus can not survive outside the womb on its own, and would take a quantum leap in technology to change that. (religion.blogs.cnn.com)
Gradually, you'll do less as your baby learns to handle the sensations of the world outside the womb on his own. (scholastic.com)