A recent report on US teenagers (G Martinez & J C Abma) has published selected data relative to sexual activity, contraceptive use and childbearing experience of 15-19 year olds deriving from the US National Survey of Family Growth (NSFG). The latter is a US survey that periodically collects data on a wider range of factors affecting family formation among 15-44 year olds. The data for this report (Martinez & Abma) comes from the latest NSFG survey for the years 2006-2010; the US Centers for Disease Control and Prevention (CDC) has previously conducted surveys for the years 1973, 1976, 1982, 1988, 1995 and 2002.
The report deals with such questions as the proportion of the 15-19 age group who are sexually experienced, the degree of contraception use at most recent sex and at first sex, and the means of contraception used. It does so in the context of trends since 1988 and before. This data is set against the background of figures for live births from 1988 to 2009. The break-down by ethnicity (non-Hispanic white; black; Hispanic) constitutes an important aspect of the report.
It must be said that the US figure for teenage “live births” (39.1 per 1000) is high by international standards, but has been declining slowly but steadily since 1988 (53 per 1000), with only a little blip for the years 2005-7. There is considerable variation by ethnicity, with live births at 70.1 and 59 for Hispanic and black respectively, as compared with 25.6 for non-Hispanic white.
The figure for teenage live births might be explained by either the extent of sexual activity or by use and methods of contraception. As regards sexual activity, there has been a slow decline in the proportion of sexually- experienced 15-19 year olds since 1988 (following a steady rise prior to that date), but for both male and female this decline appears to have flattened out since 2002. The proportions now stand at 43% and 42% (females and males respectively), with rates for ethnic groups converging to the point of statistical insignificance.
As regards use of contraception at most recent, and first intercourse, there has been, once again, little change since the 2002 survey, with rates having risen prior to then. Rates stand at 86% and 93% for most recent sex and 78% and 85% for first sex. Here, however, ethnicity seems to play a role. There is a full 11 percentage points of difference between the use of contraception at first sex by black and white females respectively; Hispanic males are less likely to have used contraception than non-Hispanic whites at last sex; proportions using the pill at last sex diverge considerably, with the figure standing at 39% for non-Hispanic whites, as compared with 14% and 17% for non-Hispanic blacks and Hispanics, respectively. The authors therefore attribute variation by ethnicity for live births to the use and method of contraception.
This report provides little in the way of international comparisons. Nor does the organization and selection of data seem particularly designed to reflect the need for a comparative approach. So, if you are approaching this report with an interest in testing out claims frequently made about high US teenage pregnancy and its association with comparatively limited use of the pill as compared with other countries (e.g. Netherlands and France), you will be disappointed !
http://www.ncbi.nlm.nih.gov/pubmed/21548441