health_maternal_infant_county_year
Maternal and infant health outcomes by county. CDC WONDER natality data: low birthweight rate, preterm birth rate, teen birth rate, and infant mortality rate.
tier badmin_record
overview
overview
~570 county-year rows populated (suppression heavy - most small-county years are suppressed under WONDER's <10-events rule).
current vintage — 2024 provisional
history — CDC WONDER natality: 1995-present; linked infant death: 1995-present
provenance
source & licensing
authority
U.S. Centers for Disease Control and Prevention
dataset
CDC WONDER Natality and Linked Birth-Infant Death
source url
methodology
license
Public domain (U.S. Federal Government work)
citation
U.S. Centers for Disease Control and Prevention. WONDER Natality and Linked Birth-Infant Death Files, 2018-2024.
schema
fields
| name | type | definition |
|---|---|---|
| ama_birth_share_pct | float64 · percent (0–100) | Advanced maternal age births as a share of total births in the county, expressed as a percentage. Calculated as ama_births / total_births × 100. |
| ama_births | int64 · count | Number of births to mothers of advanced maternal age (AMA), typically defined as age 35 or older at time of delivery. |
| country_id | string | ISO alpha-2 country code (always 'US' for domestic tables). |
| county_idkey | string | 5-character FIPS code identifying the county.Joins dim.counties on county_id. |
| infant_deaths | int64 · count | Number of deaths among infants under one year of age recorded in the county for the given year. Serves as the numerator for infant_mortality_rate. |
| infant_mortality_rate | float64 · rate per 1,000 | Number of infant deaths (under age 1) per 1,000 live births in the county for the given year. Higher values indicate worse infant survival outcomes. May be flagged as unreliable when based on small counts; see infant_mortality_rate_unreliable. |
| infant_mortality_rate_unreliable | bool | Flag indicating that the infant_mortality_rate estimate is statistically unreliable, typically because the underlying death count is fewer than 20. Rates flagged true should be interpreted with caution or suppressed in public-facing outputs. |
| known_weight_births | int64 · count | Number of births for which a birth weight was recorded. Used as the denominator when calculating low and very low birthweight rates. |
| lbw_births | int64 · count | Number of births with a recorded birth weight below 2,500 grams, meeting the clinical definition of low birthweight. |
| live_births | int64 · count | Number of live births recorded in the county for the given year. Serves as the denominator for infant_mortality_rate and may differ from total_births if stillbirths are included in the latter. |
| low_birthweight_rate | float64 · percent (0–100) | Share of births with known weight that were low birthweight (<2,500g), expressed as a percentage. Calculated as lbw_births / known_weight_births × 100. Higher values indicate worse maternal-infant health outcomes. |
| state_id | string | 2-character FIPS code identifying the state.Joins dim.states on state_id. |
| teen_birth_share_pct | float64 · percent (0–100) | Teen births as a share of total births in the county, expressed as a percentage. Calculated as teen_births / total_births × 100. Higher values indicate a greater prevalence of adolescent childbearing. |
| teen_births | int64 · count | Number of births to mothers aged 15–19 in the county for the given year. |
| total_births | int64 · count | Total number of births recorded in the county for the given year, including live births and any stillbirths captured by the source. |
| very_low_birthweight_rate | float64 · percent (0–100) | Share of births with known weight that were very low birthweight (<1,500g), expressed as a percentage. Calculated as vlbw_births / known_weight_births × 100. Higher values indicate worse maternal-infant health outcomes. |
| vlbw_births | int64 · count | Number of births with a recorded birth weight below 1,500 grams, meeting the clinical definition of very low birthweight. |
| yearkey | int64 | Reference year of the observation. |
relationships
joins
primary key
county_id, year
common joins
dim.geographies on county_id
demographics_population_county_year on (county_id, year)
health_mental_health_county_year on (county_id, year)
usage
how to use this table
method
Birth certificates aggregated to maternal residence county. Infant mortality rate = (infant deaths under 1 year) / (live births) x 1000. <10 events suppressed; <20 unreliable flag set.
do not use for
Small-county trend analysis (heavy suppression); racial subgroup at small-county; preterm vs term detail beyond what WONDER exposes; current year (provisional, subject to substantial revision).
known issues
Heavy suppression: <570 county-years populated of >18,000 possible. Watch the unreliable flag (suppresses display when <20 events).
← previousus_health.health_environmental_burden_county_yearnext →us_health.health_mental_health_county_year
last updated · May 5, 2026