NCHStats

Questions for Joyce A. Martin, M.P.H., Demographer, Statistician, and Lead Author on “Births: Final Data for 2015”

Q: Was there a result in your study’s analysis of births in the United States that you hadn’t expected and that really surprised you?

JM: Although small, (from 9.57% to 9.63%) the rise in the preterm birth rate (births of less than 37 completed weeks of gestation) was unexpected. This rate had been declining steadily since 2007.

Also of note is the decline in the triplet and higher-order multiple birth rate, down 9% from 2014 to 2015, and a decrease of 46% since 1998. The year 2015 also is the third straight year of declines in the rate of cesarean delivery (rate of 32.0% in 2015).

The continued, large decline in the teen birth rate (down 8% from 2014 to 2015) was also somewhat surprising, although not unprecedented. From 2007 through 2014, the teen birth rates had declined 7% annually.

Q: What is the difference between this new births report and the other reports your office produced on 2015 birth data, like the preliminary data report on 2015 births and the Data Brief on teen births?

JM: The annual report “Births: Final Data for 2015” offers substantially more detail (e.g., age, race and Hispanic origin of mother, state) on key topics, than does the report on preliminary birth statistics (“Births: Preliminary Data for 2015”). The final report also includes information on topics not included in the preliminary reports such as multiple births, attendant and place of birth, birth order and birth rates for fathers.

Q: How has the number of births in the United States changed in 2015 from previous years?

JM: The number of births in the United States declined slightly in 2015 (by 9,579 births to 3,978,497) from 2014. The decline for 2015 followed an increase in births for 2014, which was the first increase since 2007.

Q: What differences, if any, did you see among race and ethnic groups, and among various ages?

JM: Of continued concern are the higher risks of poor birth outcomes as measured by levels of preterm birth and low birthweight among non-Hispanic black mothers compared with total births and other race and Hispanic origin groups. For example, in 2015 the preterm birth rate for births to non-Hispanic black mothers was more than 50% higher at 13.41% than for non-Hispanic white women (8.88%) and nearly 50% higher than the rate for births to Hispanic mothers (9.14%).

Q: Did you observe any regional or state differences in this study on births?

JM: Differences by state were observed for many of the demographic and medical/health items included in the 2015 final birth report. For example, from 2014 to 2015, the general fertility rate–which is the number of births per 1,000 women aged 15–44–declined in eight states and was essentially unchanged in the 42 states and the District of Columbia (DC). In 2015, the general fertility rate ranged among states from 51.1 births per 1,000 women aged 15–44 in Vermont to 78.2 in South Dakota.

Also, increases in preterm birth rates were limited to four states from 2014 to 2015: Arkansas, California, Nebraska, and North Carolina. Rates declined in four states: Montana, New York, Texas and Wyoming. Nonsignificant differences were reported for the remaining states and DC.