NCHS has released provisional estimates of selected reproductive indicators from birth data for 2014 through the second quarter of 2016. Estimates for 2014 and 2015 are based on final data.
The estimates for the first and second quarter of 2016 are based on all birth records received and processed by NCHS as of August 28, 2016.
Estimates are presented for: general fertility rates, age-specific birth rates, total and low risk cesarean delivery rates, preterm birth rates 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. Future quarterly releases will include additional birth indicators from natality data.
Quarterly estimates are compared with estimates for the same quarter of the preceding year; for example, the second quarter of 2016 is compared with the second quarter of 2015. 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.