Fetal Mortality Data Technical Notes
DefinitionsA fetal death is a death prior to the complete expulsion or extraction from its mother of a product of conception; the fetus shows no signs of life such as breathing or beating of the heart, pulsation of the umbilical cord, or definite movement of voluntary muscles. Fetal deaths are also referred to as stillbirths, miscarriages, or spontaneous abortions.
An infant death differs from a fetal death in that it is a death of a live-born infant within the first year of life. Infant death data are in the Infant Mortality Query.
Sources of Data
Fetal DeathsThe fetal death certificate is the source document for the fetal death data in NJSHAD. Fetal deaths occurring after the completion of 20 or more weeks of gestation are required to be reported to the State Registrar by New Jersey law. Induced abortions of 20 weeks or more gestation are encompassed by this requirement, but are not included in the fetal death count. Fetal death figures presented in NJSHAD, therefore, include only spontaneous fetal deaths (also called stillbirths) beyond 19 weeks of gestation. Fetal deaths of unknown or unstated gestational age are also included. Only fetal deaths occurring to females who were New Jersey residents are included.
BirthsBirth certificate data are used to calculate fetal mortality rates. The birth certificate is the source document for these data. New Jersey law requires that the attending physician, midwife, or person acting as midwife file a certificate of birth with the Local Registrar within five days of a birth within the state.
Out-of-State Fetal DeathsStatistics on fetal deaths to New Jersey resident mothers which occurred in other states are obtained through participation in the national Vital Statistics Cooperative Program (VSCP), which encourages the exchange of information on vital events between the states of occurrence and residence. The fetal mortality data presented in the query system are for New Jersey residents, regardless of where the death occurred.
Data File UpdatesThe fetal death data in the query system were generated from data files available at the time of preparation of the back-end dataset. Any data pertaining to a fetal death for which a certificate was filed after that time or relating to corrections or revisions made since the data were processed for the electronic file are not included. Vital events computer files are periodically updated by the New Jersey Department of Health's Bureau of Vital Statistics and Registration (BVS) and Center for Health Stastistics (CHS) staff based on correction reports received from local registrars and from data quality control analyses conducted by CHS. The query incorporates data from the most recently updated files.
Quality of DataThe completeness of fetal death reporting by residence is dependent on the effective functioning of the interstate data exchange program for certificates which is fostered and encouraged by the National Center for Health Statistics (NCHS). Research has shown that there is some degree of slippage in receiving information on all vital events of New Jersey residents occurring in other states. However, the number of missing events is thought to be small, relative to the overall number of events.
The quality of the data included in the query is a function of the accuracy and completeness of the information recorded on the respective certificates and of the quality control procedures employed in the coding and keying processes. A query program in which the individual(s) responsible for completing the certificate is questioned about missing or conflicting information is carried out by BVS staff. This process is augmented by the data quality control analyses performed by the CHS using all of the NCHS edit criteria.
Allocation of Data by Residence or OccurrenceFor public health planning and policy determination, the most useful population to study is usually the resident population of an area. In the case of vital events, the existence of resident certificate exchange agreements among the registration areas in the country permits analysis of resident vital event statistics regardless of where the event occurred. In the query system, the data presented represent fetal deaths to New Jersey resident mothers, regardless of where they occurred. Fetal deaths that occurred in New Jersey to non-NJ residents are not included.
Allocation of vital events by place of residence within the state is sometimes difficult because classification depends on the statement of the usual place of residence provided by the informant at the time the certificate is completed. For a variety of reasons, the information given may be incorrectly recorded. A common source of error is the confusion of mailing address with residence address. For this reason, all records are run through geocoding software to properly assign the county and municipality of residence.
Race, Ethnicity, and NativityOne race group (White, Black, American Indian/Alaska Native, Chinese, Japanese, Hawaiian, Filipino, Asian Indian, Korean, Samoan, Vietnamese, Guamian, other Asian/Pacific Islander, other race, and an unknown race category) and an ethnicity (Non-Hispanic, Mexican, Puerto Rican, Cuban, Central or South American, other Hispanic, and an unknown ethnicity category) are recorded for each parent of each individual for whom a fetal death certificate is filed. Race and ethnicity of the child are not recorded and that of the mother is used for statistical analysis. Race and ethnicity can be combined to make a Hispanic "race" group and this is the standard way the New Jersey Department of Health reports vital event data.
Race/ethnicity designations used in the fetal mortality query are White, Black, Hispanic, Asian, Native Hawaiian/Other Pacific Islander, American Indian/Alaska Native, and Other Single Race, where Hispanics may be of any race and the other race groups do not include Hispanics (but include those with ethnicity not stated). The Hispanic category includes persons of Mexican, Puerto Rican, Cuban, Central/South American, or other Hispanic ethnicity, regardless of race. The Asian category includes persons of Chinese, Japanese, Filipino, Asian Indian, Korean, Vietnamese, and other Asian descent. The Native Hawaiian/Other Pacific Islander category includes persons of Hawaiian, Samoan, Guamian, and other Pacific Islander descent. The Other Race category includes all race groups other than White, Black, Asian, Native Hawaiian/Pacific Islander, and American Indian/Alaska Native. When combining race and ethnicity, Hispanic ethnicity takes precedence over whatever race is recorded for the mother.
Three nativity categories are used in the query: native-born, Puerto Rico-born, and foreign-born. Native-born includes mothers born in the 50 states or Washington, D.C. Foreign-born includes mothers born anywhere other than the 50 states, D.C., and Puerto Rico. Foreign-born, therefore, includes other U.S. territories such as American Samoa, Guam, and U.S. Virgin Islands because all territories are not coded separately in the electronic fetal death files. Foreign-born also includes those born abroad to American parents because fetal death certificates do not have an item to distinguish those cases. Numbers of fetal deaths to New Jersey residents born in territories other than Puerto Rico or born abroad to American parents are extremely small.
Cause of Death RankingsRankable causes of death in the fetal mortality query are based on 45 distinct causes of death derived from the NCHS List of 124 Selected Causes of Fetal Death.
New Jersey also uses a list of 6 cause groups and one residual category modified from the 45 Cause List that groups causes of death that rarely occur among New Jersey residents. This list may also be used for ranking causes of death with the caveat that "Other than Leading Causes" is not eligible to be ranked.
RatesThe presentation of fetal mortality rates facilitates comparisons between geographic areas with populations of different sizes or between subgroups of a population. Fetal mortality rates are calculated by dividing the number of fetal deaths of 20 or more weeks gestation to resident mothers of an area or demographic subgroup by the number of births plus fetal deaths of 20 or more weeks gestation to the residents of the same area or subgroup and are usually expressed per 1,000 births plus fetal deaths of 20 or more weeks gestation. Fetal deaths are limited to those that occur within a specific time period, usually a year, and the birth data used for rate calculation is that of the same year.
In order to compare fetal death experiences among various maternal ages and races/ethnicities, fetal mortality rates may be computed for subgroups of the population. These are referred to as age- or race/ethnicity-specific rates and are calculated by dividing the number of fetal deaths of 20 or more weeks gestation within a subgroup by the births plus fetal deaths of 20 or more weeks gestation in the subgroup. Fetal death rates from specific causes may also be calculated, with the numerator consisting of the deaths from the particular cause in an area and the denominator comprised of births plus fetal deaths of 20 or more weeks gestation in the same time period.
The definition of rates used in the query system are on the Definitions of Public Health Terms and Acronyms page . It should be noted that alternative forms exist for some of these statistics. Some other states and the federal government may employ different formulae for the computation of selected rates.