Preterm birth is a birth with less than 37 weeks gestation based on the obstetric estimate of gestational age. Data used in this report card came from the National Center for Health Statistics (NCHS) natality files, as compiled from data provided by the 57 vital statistics jurisdictions through the Vital Statistics Cooperative Program.¹ This national data source was used so that data are comparable for each state and jurisdiction-specific report card. Data provided on the report card may differ from data obtained directly from state or local health departments and vital statistics agencies due to timing of data submission and handling of missing data. The preterm birth rates shown at the top of report card was calculated from the NCHS 2019 final natality data. Preterm birth rates in the trend graph are from the NCHS 2009-2019 final natality data. County preterm birth rates are from the NCHS 2018 final natality data. Preterm birth rates for bridged racial and ethnic categories were calculated from NCHS 2016-2018 final natality data. Preterm birth rates were calculated as the number of premature births divided by the number of live births with known gestational age multiplied by 100.

Infant mortality rates were calculated using the NCHS 2018 period linked infant birth and infant death data. Infant mortality rates were calculated as the number of infant deaths divided by the number of live births multiplied by 1,000. Infant mortality rate in the trend graph are from the NCHS 2008-2018 file.

Mother's race and Hispanic ethnicity are reported separately on birth certificates. Rates for Hispanic women include all bridged racial categories (white, black, American Indian/Alaska Native and Asian/Pacific Islander). Rates for non-Hispanic women are classified according to race. The Asian/Pacific Islander category includes Native Hawaiian. To provide stable rates, racial and ethnic groups are shown on the report card if the group had 20 or more preterm births in each year from 2016-2018. To calculate preterm birth rates on the report card, three years of data were aggregated (2016-2018). Preterm birth rates for not stated/unknown race are not shown on the report card.

Report cards for states and jurisdictions, except District of Columbia, display the city and up to 6 counties with the greatest number of live births. Cities are not displayed for Delaware, Maine, Vermont, West Virginia and Wyoming due to limited availability of data. Counties are not displayed if the number of premature births is less than 20. Counties are ordered alphabetically. Grades were assigned based on the grading criteria described above. Change from previous year was calculated by comparing the 2018 city or county preterm birth rate to the 2017 rate.

The March of Dimes disparity ratio is based on Healthy People 2020 methodology and provides a measure of the differences, or disparities, in preterm birth rates across racial/ethnic groups within a geographic area.² The disparity ratio compares the racial/ethnic group with the lowest preterm birth rate (comparison group) to the average of the preterm birth rate for all other groups.

Progress toward eliminating racial and ethnic disparities was evaluated by comparing the 2016-2018 disparity ratio to a baseline (2010-2012) disparity ratio. Change between time periods was assessed for statistical significance at the 0.05 level using the approach recommended by Healthy People 2020.² If the disparity ratio significantly improved because the average preterm birth rate for all other groups got better, we displayed "Improved" on the report card. If the disparity ratio significantly worsened because the lowest group got better or the average of all other groups got worse, we displayed "Worsened" on the report card. If the disparity ratio did not significantly change, we displayed "No Improvement" on the report card.

The report card also provides the percent difference between the racial/ethnic group with the 2016-2018 highest preterm birth rate compared to the combined 2016-2018 preterm birth rate among women in all other racial/ethnic groups. This percent difference was calculated using only the racial/ethnic groups displayed on the state or jurisdiction-specific report card. This difference was calculated for each U.S. state with adequate numbers and the District of Columbia.

March of Dimes recognizes the importance of certain risk factors that are associated with preterm birth. Three of these contributing factors are highlighted for each state. We reference target goals for these three measures from Healthy People 2030.³ These risk factors are poverty in women (age 15-44 years), lack of health insurance in women (15-44 years) and inadequacy of prenatal care.

A woman was considered uninsured if she was not covered by any type of health insurance.⁴ The uninsured percent is calculated among women ages 15-44 in 2018. Persons in poverty are defined as those who make less than 100% of the poverty threshold established by the US Census Bureau.⁵ The Federal poverty threshold for a family of three was $20,598 in 2019. Poverty is reported for women 15-44 years in 2017-2019. Adequacy of prenatal care is measured using the Adequacy of Prenatal Care Utilization Index, which classifies prenatal care received into 1 of 4 categories (inadequate, intermediate, adequate and adequate plus) by combining information about the timing of prenatal care, the number of visits and the infant's gestational age.⁶ Inadequate prenatal care is defined as a woman who received less than 50% of her expected visits.

A growing number of studies indicate that Medicaid expansion has reduced the rate of women of childbearing age who are uninsured, improved health outcomes and helped to reduce disparities, including lower rates of premature birth and low birthweight for Black infants in expansion states. ^7,8

Medicaid Expansion is provided from the Kaiser Family Foundation as adopted or not adopted. Medicaid expansion has reduced the rates of uninsured. Increased access and utilization of health care are significantly associated with Medicaid expansion.⁹

Advocacy for Medicaid extension by the Equitable Maternal Health Coalition (EMHC) supports that adoption of the policy allows women to avoid disruption to healthcare during the postpartum period and by maintaining access to healthcare, improves both maternal and child health outcomes. ¹⁰ Extending this coverage typically requires both state legislation and an appropriation in addition to a Section 1115 waiver in order to receive federal match. ¹⁰ Medicaid extension status is provided by the American College of Obstetricians and Gynecologists (https://www.acog.org/advocacy/policy-priorities/extend-postpartum-medicaid-coverage) as adopted and/or in development or not adopted and/or not developing. States who have had the following actions- the policy extension introduced, enacted or is currently implemented to some degree, are categorized as having recent action.

Updated average preterm birth cost (2016) for state and District of Columbia utilized the 2007 Institute of Medicine's (IOM) study. ¹¹ Preterm Birth: Causes, Consequences and Prevention served as the foundation for updating costs to 2016 and for providing separate estimates for each state and the District of Columbia. ¹² Costs were updated adjusting for price changes over time and for variation in prices of services between states. Changes in the rate of preterm birth, the distribution of preterm birth by gestational age (GA), and the rate of infant mortality by GA at the national and state levels were also incorporated. This cost of preterm birth estimates are the most comprehensive national estimates to date, and provide the first profile of such costs by state for every state and the District of Columbia. Measure is provided as either above or below the calculated U.S. average.

The committees can be made up of representatives from public health, nursing, maternal-fetal medicine, obstetrics and gynecology, midwifery, patient advocacy groups and community-based organizations. ¹³ The majority of pregnancy-related deaths are preventable. ¹⁴ States that have an MMRC are better equipped to prevent pregnancy-related deaths by having a better understanding of what is causing them in their state or city. The measure is provided by the CDC ERASE MM Program (https://www.cdc.gov/reproductivehealth/maternal-mortality/erase-mm/index.html) and is categorized as having and/or developing the committee, having the committee with funding from CDC, or not having or developing the committee.

The PQC involves partnerships with families, key state agencies and organizations in order to identify and initiate programs or procedures that increase the quality of care in clinical settings. PQC's work focus on collaborative learning among healthcare providers and the PQC. ¹⁵ Data is provided by the CDC at: https://www.cdc.gov/reproductivehealth/maternalinfanthealth/pqc-states.html and the measure is reported as either having and/or developing the collaborative, having the collaborative with funding from CDC, or not having and/or developing the collaborative.

All natality calculations were conducted by the March of Dimes Perinatal Data Center. Calculations for the cost of preterm birth were conducted by the University of Utah.

To prevent maternal and infant deaths, we need to better understand the causes of severe maternal morbidity (SMM) and those most impacted by it, including racial and ethnic disparities. This starts by standardizing data collection and reporting for maternal and infant health across the U.S. These data will help us to examine factors contributing to SMM, preventable deaths and poor birth outcomes in order to develop evidence-based solutions. To this end, future Report Cards will assess overall rates and disparities of SMM, low-risk cesarean sections and measures of equity in maternal and infant health. Additional details on these future measures can be found here.