Table 8.1. Glossary of Terms.
Term	Definition
Neonatal	Pertaining to the period of time from birth to the fourth week after birth.
Perinatal	Pertaining to the period of time from the completion of 28 weeks of gestation to 1-4 weeks after birth.
Post-neonatal	Pertaining to the period from the fourth week after birth to the end of the first year.
Preterm	An infant born between the twentieth week and the thirty-eighth week of gestation (134 to 266 days). Normal gestation is approximately forty weeks.
Low Birthweight (LBW)	Birthweight of less than 2,500 grams (5 lbs., 8 oz.).
Very Low Birthweight(VLBW)	Birthweight of less than 1,500 grams (3 lbs., 4 oz.).
Mortality	The death rate, usually reported as the ratio of number of deaths to a given population.
Morbidity	The disease rate, usually reported as the ratio of persons with a particular disease to a given population.
Infant Mortality	The rate of death that occurs between birth and the end of the first year, which includes both the neonatal and post-neonatal periods.
Sources: Thomas, C. L., Taber's Cyclopedic Medical Dictionary. Philadelphia: F.A. Davis Company, 1973. National Vital Statistics Report, April 29, 1999, volume 47, number 18. UNICEF (United Nations Children's Fund), The State of the World's Children 2000. New York: Oxford University Press, 2000.