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Source
of Birth Data
Information on Colorado births
is collected from the Certificate of Live Birth. Data items are presented
as reported on the certificate. Completeness and accuracy of items on
the birth certificate may vary by facility and year. Data for all births
that occurred within the state of Colorado, resident and nonresident,
are collected; however, at this time, CoHID only reports data for Colorado
resident births. Resident births are births to those individuals who reported
being residents of Colorado, even if the birth occurred to residents while
outside of Colorado. Interstate agreements allow for the exchange of vital
information about births to Colorado residents that occurred in other
states. County-specific data are for births reported as occurring for
residents of those counties.
Clarifications
on Birth Data
Race/Ethnicity
In 1989 the National Center for Health Statistics
adopted the use of race/ethnicity of the mother for birth data, rather
than race/ethnicity of the child, as a standard classification. Since
that time Colorado birth statistics have also been presented by race/ethnicity
of the mother.
Race and ethnic backgrounds are determined by responses
to race and Hispanic origin questions on the birth certificate. In order
to best approximate the race and ethnic groups found among the Colorado
population, and to follow standard measures of race, CoHID presents
the following race categories: all, white, black, Asian, and American
Indian. Used together with ethnicity (all, Hispanic, and non-Hispanic),
most combinations of race and ethnicity found in Colorado can be constructed.
The unknown category is used to classify those cases where
race was either stated as unknown or left blank on the certificate.
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Gestational
Age
A birth that is less than 37 weeks gestation is defined
as preterm. Preterm birth is a major cause of infant mortality. Preterm
babies are also at greater risk of neurodevelopmental and respiratory
disorders.
CoHID presents the clinical estimate of gestational age
at birth, which is determined by the physician attending the birth and
is based on physical examination of the infant.
Prenatal
Care
Early entry into prenatal care can promote healthier births
by detecting and managing pre-existing medical conditions and providing
health behavior advice.
"Early entry into prenatal care" is care
started in the first trimester (first 3 months) of pregnancy. "Late
prenatal care" has been interpreted in two different ways.
The more traditional definition, used by the National Center for Health
Statistics, includes care started in the third trimester, care at delivery
only, and no care. More recently, however, a new definition of "late
prenatal care," based on the Health Status Indicator for
the Year 2000. U.S. Department of Health and Human Services, was introduced
as care beginning later than the first trimester.
The Health Status Indicator for the Year 2010 is
to increase to at least 90 percent the proportion of all pregnant women
who receive prenatal care in the first trimester.
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Multiple
(Plural) Births
According to the National Center for Health Statistics
(NCHS), multiple births are at greater risk than singletons of being
born too early and too small and, accordingly, of not surviving the
first year of life.
NCHS has reported that much of the increase in multiple
births has been related to the increased use of fertility-enhancing
techniques. Birth certificate data do not indicate whether a birth resulted
from the use of fertility-enhancing techniques.
Birth
Weight
By definition, a newborn weighing less than 2,500 grams
(less than 5lb 9oz) is considered a low weight birth. A newborn weighing
less than 1,500 grams (less than 3lb 5oz) is considered a very low weight
birth. According to the National Center for Health Statistics, infants
born at low weight are at much greater risk for long-term morbidity
and early death.
Studies have identified a number of risk factors for low
birth weight, including insufficient weight gain during pregnancy, maternal
smoking, younger and older maternal age, low socioeconomic status, low
level of mother's education, late entry into prenatal care, and substance
abuse during pregnancy. Multiple births are most likely to be born too
small.
Birth
Rates and Fertility Rates
A
birth rate is the number of births that occur within a certain
population (or area) over a specified time period in relation to the
total population of the area. Specifically, it is the number of births
per 1,000 total population.
A
fertility rate is the measure of fertility (births) among the
females of a population. The general fertility rate measures the fertility
among women of childbearing age, defined as ages 15-44. The general
fertility rate is the total number of births per 1,000 females ages
15-44 in the population. An age-specific fertility rate is the number
of births for a specified age group per 1,000 females in the age group.
Because birth rates and fertility rates are derived using
population estimates, these rates are sensitive to changes in the methods
used for estimating populations. The fertility rates derived from CoHID
for some age groups may vary from those published in other reports due
to the changes in the methods used for calculating the population estimates.
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Data
Quality
Many quality control edits are built into the data reporting
and compilation system on CoHID. However, as with all large, complex
data sets, completeness and accuracy of reporting may vary by individual
data item. Birth data are presented as reported on birth certificates.
The unknown category is used to classify those cases where the value
or characteristic was either stated as unknown or left blank on the
certificate.
Confidentiality
Birth records are confidential in accordance with Colorado
statutes (Section 25-2-117). To maintain confidentiality and prevent
the identification of an individual, the results of any search returning
fewer than three events will be suppressed.
Definitions
Birth
Rate: The number of births that occur
within a certain population or geographical area, over a specified time
period, in relation to the total population of the group or area. Specifically,
the number of births per 1,000 total population.
Birth to Unmarried Woman:
A mother is considered to be unmarried if she was not married at the
time of conception and did not marry at any time between conception
and delivery. Common-law marriages are recognized as legal marriages
in Colorado.
Birth Weight: The first weight
of the fetus or newborn obtained after birth. This weight preferably
is measured within the 1st hour of life, before a significant postnatal
weight loss has occurred.
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Fertility Rate (age-specific):
The number of births for a specified age group of females within a certain
population or area per 1,000 total females in the age group.
General Fertility Rate:
A measure of the fertility among women of childbearing age, defined
as ages 15-44. Specifically, the number of births to all females over
a certain time period per 1,000 females aged 15-44 in the population.
Gestation age: Completed
weeks of pregnancy from the first day of the mother's last normal menstrual
period.
Live Birth: The complete
expulsion or extraction from its mother of a product of conception,
irrespective of the duration of pregnancy, which, after such separation,
breathes, or shows any other evidence of life, such as beating of the
heart, pulsation of the umbilical cord, or definite movement of voluntary
muscles, whether or not the umbilical cord has been cut or the placenta
is attached; each product of such a birth is considered live born. Birth
data on CoHID are for live births only.
Low Weight Birth:
Birth weight of less than 2,500 grams (less than 5lb 9oz). A very
low weight birth is less than 1500 grams (less than 3lb 5oz).
Multiple Birth: More
than one child born resulting from a single pregnancy. Also called plural
birth.
Perinatal: Pertaining
to or occurring in the period shortly before and after birth. There
are several commonly used definitions for the perinatal period, extending
from 20 weeks of gestation to 4 weeks after birth.
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Postterm: Births occurring
at a gestational age greater than or equal to 42 weeks (>293 days).
Premature Birth: Birth
occurring prior to 37 completed weeks of gestation, but after that stage
of viability at about 20 weeks gestation.
Prenatal: Existing or occurring
before birth.
Prenatal Care: Medical
care during pregnancy before birth.
Prenatal Visits:
The number of visits made to a physician or other health care provider
during the prenatal period for medical supervision of a pregnancy.
Preterm: Births occurring
prior to 37 completed weeks of gestation (<259 days).
Singleton: Single birth.
Term: Births occurring between
37 and 41 completed weeks of gestation (259-293 days).
Trimester: A 3-month period
of time. First trimester care, for example, refers to care initiated
in the 1st three months of pregnancy.
For more information on birth data not contained on CoHID,
or for data prior to 1990, please contact the Health Statistics Section
of the Colorado Department of Public Health and Environment at (303) 692-2160.
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