Ask the Expert: Dr. Brady Hamilton

Data Brief 89, “Birth Rates for U.S. Teenagers Reach Historic Lows for All Age and Ethnic Groups,” published in April 2012, is available for download from the NCHS website.

Birth rates for U.S. teenagers have reached historic lows for all age and ethnic groups, according to a recent NCHS Data Brief.  We spoke with Brady Hamilton, Ph.D., one of NCHS’s natality experts, about tracking teen births, what’s new in the report, and a surprising trend.

How long have you been keeping track of births among U.S. teenagers?

We’ve tracked births by age of the mother for quite some time.  We look at birth data for all ages, not just teens.  It gives us a very detailed picture of what’s happening in the country in terms of fertility and childbearing patterns.

There’s a lot of interest in births to teens because it is a crucial time in their lives.  They’re preparing to enter the work force and/or continue with their education.  And that, of course, can have a substantial impact on the country as a whole.

Where do the data come from?

The data come from state birth certificates, which tell us a lot—age of mother, gestational age, birth weight, smoking patterns of the mother, and so on.  What the data from birth certificates does not tell us, of course, is why.  What were the parents thinking?  What decisions were they making, or not?  For that, we rely on the National Survey of Family Growth.  We also count on that for information on contraceptive use and changes in sexual behavior.

This latest data brief on teen births includes information you’ve never included before.  Can you describe it?

We included a couple of new things.  First, we’ve provided a detailed geographical breakdown, state by state, of teen birth rates.  This was in response to regional interest in teen birth data, and has been welcomed by state officials as well as the general public.

We’ve also been able to turn the abstract into the concrete, and project the births to teens that did not occur.  If teens had continued to give birth at 1991 rates, there would be an estimated 3.4 million additional total births to teenagers from 1992 through 2010.

What agencies do you collaborate with in creating these reports?

First and foremost, we work with the states, independent reporting areas, and U.S. territories to collect birth certificate data and produce the national statistics.  Their state data are the source of our national data.  We also work with a number of other federal agencies, in particular the U.S. Census Bureau, which provides us with the populations used to compute the birth and fertility rates in our reports.

Any new trends you’d like to let us in on?

I think the one to watch is the cesarean delivery rate.  Currently, about a third of all births in the United States are delivered by cesarean.  That is astounding.  Cesarean delivery rate had been rising steadily from 1996, when about a fifth of births were delivered by cesarean.  However, in 2010 the cesarean delivery rate declined for the first time since 1996.  That is noteworthy.

Dr. Hamilton will discuss “Results of the 2010 Census: Impact on Trends and Variations in Population and Health Statistics” at the National Conference on Health Statistics, Tuesday, August 7, from 10:30 a.m. to 12:00 p.m.  Visit the Conference page to register.