|Classification and external resources|
Infant, neonatal, and postneonatal mortality rates: United States, 1940-2005
Perinatal mortality (PNM), also perinatal death, refers to the death of a fetus or neonate and is the basis to calculate the perinatal mortality rate. Variations in the precise definition of the perinatal mortality exist specifically concerning the issue of inclusion or exclusion of early fetal and late neonatal fatalities. The World Health Organization defines perinatal mortality as the "number of stillbirths and deaths in the first week of life per 1,000 live births, after 24 weeks gestation", but other definitions have been used.. The UK national figure is about 8 per 1,000 and varies markedly by social class with the highest rates seen in Asian women.
Preterm birth is the most common cause of perinatal mortality, causing almost 30 percent of neonatal deaths. Infant respiratory distress syndrome, in turn, is the leading cause of death in preterm infants, affecting about 1% of newborn infants. Birth defects cause about 21 percent of neonatal death.
Fetal mortality 
Fetal mortality refers to stillbirths or fetal death. It encompasses any death of a fetus after 20 weeks of gestation or 500 gm. In some definitions of the PNM early fetal mortality (week 20-27 gestation) is not included, and the PNM may only include late fetal death and neonatal death. Fetal death can also be divided into death prior to labor, antenatal (antepartum) death, and death during labor, intranatal (intrapartum) death.
Neonatal mortality 
Early neonatal mortality refers to a death of a live-born baby within the first seven days of life, while late neonatal mortality covers the time after 7 days until before 28 days. The sum of these two represents the neonatal mortality. Some definitions of the PNM include only the early neonatal mortality. Neonatal mortality is affected by the quality of in-hospital care for the neonate. Neonatal mortality and postneonatal mortality (covering the remaining 11 months of the first year of life) are reflected in the Infant Mortality Rate.
Perinatal Mortality Rate 
The PNMR refers to the number of perinatal deaths per 1,000 total births. It is usually reported on an annual basis. It is a major marker to assess the quality of health care delivery. Comparisons between different rates may be hampered by varying definitions, registration bias, and differences in the underlying risks of the populations.
PNMRs vary widely and may be below 10 for certain developed countries and more than 10 times higher in developing countries . The WHO has not published contemporary data.
See also 
- "WHO | Health Status Statistics: Mortality".
- Richardus JH, Graafmans WC, Verloove-Vanhorick SP, Mackenbach JP (January 1998). "The perinatal mortality rate as an indicator of quality of care in international comparisons". Med Care 36 (1): 54–66. PMID 9431331.
- March of Dimes --> Neonatal Death Retrieved on September 2, 2009
- Rodriguez RJ, Martin RJ, and Fanaroff, AA. Respiratory distress syndrome and its management. Fanaroff and Martin (eds.) Neonatal-perinatal medicine: Diseases of the fetus and infant; 7th ed. (2002):1001-1011. St. Louis: Mosby.