Timing of prenatal care in the United States: how accurate are our measurements?

Timing of prenatal care has become the most widely used indicator of adequacy of care, largely because it is easy to measure and is obtained by national data collection sources. Because it is a crucial input into setting policy goals, it is important that we have an accurate measure of timing of care. This article reviews the existing level of access to prenatal care, as measured by three different national data sources (Vital Statistics, the National Natality Survey, and the National Survey of Family Growth). Differences among the three sources are discussed; and drawing upon what we know of the problems of data collection, we speculate on the most accurate measure of access to care. Finally, suggestions for improving future data collection are made.