PERINATAL MORTALITY RATE

<strong>PERINATAL</strong> <strong>MORTALITY</strong> <strong>RATE</strong><br />

1. Definition:<br />

<strong>PERINATAL</strong> <strong>MORTALITY</strong> <strong>RATE</strong> is the sum of the number of resident fetal deaths of 28 or<br />

more weeks gestation plus the number of resident newborns dying under 7 days of age in a<br />

specified geographic area (country, state, county, etc.) divided by the sum of the number of<br />

resident live births plus the number of resident fetal deaths of 28 or more weeks gestation for the<br />

same geographic area (for a specified time period, usually a calendar year) and multiplied by<br />

1,000.<br />

2. Calculation:<br />

[(Number of resident fetal deaths 28 or more weeks gestation + Number of resident newborns<br />

dying under 7 days of age) / (Number of resident live births + Number of resident fetal deaths of<br />

28 or more weeks gestation)] x 1,000<br />

(Number of Resident Fetal Deaths of 28 or more weeks gestation +<br />

Number of Resident Newborns dying under 7 days of age)<br />

(Number of Resident Live Births +<br />

Resident Fetal Deaths of 28 or more weeks gestation)<br />

X 1,000<br />

Additional links to State/National websites with calculation and/or definition -<br />

National Center for Health Statistics<br />

3. Examples:<br />

700 fetal deaths of 28 or more weeks gestation in 2008 among state residents<br />

300 newborns dying under 7 days of age in 2008 among state residents<br />

150,000 live births in 2005 among state residents<br />

[(700 + 300) / (150,000 + 700)] x 1,000 = 6.6 perinatal deaths per 1,000 live births and fetal<br />

deaths of 28 or more weeks gestation in 2008 among state residents<br />

4. Technical Notes:<br />

• There are actually two different definitions used to calculate a perinatal mortality rate.<br />

The definition shown here (sometimes referred to as Definition I) includes infant deaths<br />

of less then seven days of age and fetal deaths of 28 or more weeks gestation. The second<br />

definition used (Definition II) is more inclusive and includes infant deaths of less than 28<br />

days of age and fetal deaths of 20 or more weeks gestation. Definition I is preferred for<br />

international and state-to-state comparisons due to differences among countries/states in<br />

completeness of reporting of fetal deaths of 20-27 weeks gestation. Definition II is more<br />

useful for monitoring perinatal mortality throughout the gestational age periods since the<br />

majority of fetal deaths occur prior to 28 weeks gestation.<br />

• The perinatal mortality rate is an important and unique health status indicator since it<br />

addresses the two related issues of late fetal deaths and early infant deaths many of which<br />

are considered preventable.<br />

• Induced abortions or terminations of pregnancy are not included in the fetal death figures.<br />

• In less densely populated areas, annual numbers of perinatal deaths may be small (

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and/or expanding the area to be studied should result in a larger number of deaths and<br />

more reliable rates for analysis. (see North Carolina Statistical Primer, Problems with<br />

Rates Based on Small Numbers; Pennsylvania: Technical Assistance – Small Area<br />

Analysis; New York State: Rates Based on Small Numbers, Washington State: Guidelines<br />

for Working with Small Numbers and Statistical Notes for Health Planners)<br />

• The Division of Vital Statistics (DVS) at NCHS follows standards for use of the terms<br />

“death rate” and “mortality rate” in naming and reporting common vital statistics rates for<br />

deaths. The NAPHSIS standard measures shown here follow the DVS standards,<br />

primarily to maintain consistency with DVS for naming conventions. Please note that<br />

states/registration areas and other federal government organizations within and outside<br />

NCHS/CDC may not follow the DVS standards when naming and reporting<br />

death/mortality rates.<br />

o According to DVS standards, the following naming conventions are used for the<br />

common vital statistics rates for deaths:<br />

Mortality Rates<br />

Infant Mortality Rate<br />

Neonatal Mortality Rate<br />

Postneonatal Mortality rate<br />

Perinatal Mortality Rate<br />

Fetal Mortality Rate<br />

Maternal Mortality Rate<br />

Death Rates<br />

Crude Death Rate<br />

Age-Specific Death Rate<br />

Cause-Specific Death Rate<br />

Age-Adjusted Death Rate<br />

(03/16/09)