NCIt definition : An age group comprised of infants greater than 28 weeks, 0 days and less than 34 weeks,
0 days.;
Alternative definition : GAIA: A baby born alive with a gestational age between 28 to less than 32 weeks. (WHO); NICHD: A newborn infant greater than 28 weeks, 0 days and less than 34 weeks, 0 days.;