As PERSON@1 care has improved over the last NUMBER@1 years , viability has reduced to approximately NUMBER@2 weeks , -- in particular see TABLE NUMBER@3 Survival and Neurologic Disability Rates Among Extremely Premature Infants although rare survivors have been documented as early as NUMBER@4 weeks .

As PERSON@1 care has improved over the last NUMBER@1 years , viability has been reduced to approximately NUMBER@2 weeks .
