Quarterly Provisional Estimates for Selected Birth Indicators, 2018-Quarter 4, 2020
Provisional estimates are based on a snapshot of all vital statistics birth certificate data received and processed by NCHS as of a specified cutoff date. Provisional estimates closely match final data, but they are subject to revision in future quarterly releases as additional records for that quarter are received. See Technical Notes for more details.
In this release of Quarterly Provisional Estimates, NCHS presents estimates of selected reproductive indicators from birth data for 2018 through the fourth quarter of 2020. Estimates for 2018 and 2019 are based on final data (1); estimates for 2020 are based on provisional data. The estimates are based on all birth records received and processed by NCHS as of February 11, 2021. Estimates are presented for: general fertility rates, age-specific birth rates, total and low-risk cesarean delivery rates, and rates for preterm birth and other gestational age categories. These indicators were selected based on their importance for public health surveillance as well as the feasibility of producing reliable estimates using available provisional data (2). Future quarterly releases may include additional birth indicators from natality data. Quarterly estimates are compared with estimates for the same quarter of the preceding year. For comparability with rates for 12-month periods, the quarterly (3-month) rates have been annualized to present births per year per 1,000 population that would be expected if the quarter-specific rate prevailed for 12 months. In addition, the rates and percentages for a 12-month period ending with each quarter (i.e., 12-month moving average) are presented to account for seasonality. Estimates for the 12-month period ending with the fourth quarter in each year can be interpreted as an annual provisional estimate for that year. Differences are reported only if statistically significant (p<0.05).