Questions for Brady E. Hamilton, Ph.D., Demographer, Statistician, and Lead Author of “Births: Provisional Data for 2017”
Q: What did you think was the most interesting finding in your new analysis?
BH: The report includes a number of very interesting findings. The general fertility rate, 60.2 births per 1,000 women aged 15–44, declining 3% in 2017 and reaching a record low is certainly noteworthy. In addition, the continued decline in the birth rate for teens, down 7% from 2016 to in 2017, and reaching another record low, is very significant. The increase in the cesarean delivery rate following several years of decline is noteworthy as are the recent increase in rates of preterm and low birthweight births.
Q: Why does fertility keep going down in the U.S.?
BH: In general, there are a number of factors associated with fertility. The data on which the report is based comes from the birth certificates registered for births in the U.S. While the scope of this data is essentially all births in the country, and provides detailed information about rare events, small areas, or small population groups, the data does not provide information about the parent’s decision to have (or not have) a child. And so, accordingly, we cannot examine the “why” of the changes and trends in births.
Q: Does the decline in the Total Fertility Rate essentially mean fertility is down below “replacement” levels? Could you explain this in general terms?
BH: “Replacement” refers to a minimum rate of reproduction necessary for generation to exactly replace itself, that is, enough children born to replace a group of 1,000 women and their partners. For the total fertility rate, this rate is generally considered to be 2,100 births per 1,000 women. In 2017, the total fertility rate, 1,764.5 births per 1,000 women, was below replacement.
Q: Do the increases among women over 40 suggest a “new norm” in people waiting till much later to have children?
BH: Birth rates for women aged 40-44 and 45-49 years have increased generally over the last 3 decades. Given this, it reasonable to expect this trend to continue.
Q: Are the annual declines in teen pregnancy something that we are in danger of taking for granted?
BH: The birth rate for females aged 15-19 has decreased 8% per year from 2007 through 2017. For comparison, the decline in the birth rates for women aged 20-24 and 25-29 was 4% and 2% from 2007 through 2017. The decline in teen births is very noteworthy.
Q: Can you explain how the increases in preterm births and low birthweight are connected?
BH: Infants born preterm are also often, but not exclusively, born low birthweight and vice-versa. The causes of the recent upward shift in these rates are not well understood.