Conceptualization, measurement, and use of gestational age. I. Clinical and public health practice.

Despite its importance for both clinical and public health practice and the considerable effort spent during the past three decades to develop alternative estimation methods, the measurement of gestational age on both the individual and population level continues to be problematic. The availability of alternative approaches for the estimation of gestational age has to some extent obscured the basic differences in the conceptualization of these measures and influenced our current state of thinking about gestational age. As the evidence grows that these alternative gestational age estimation measures do not precisely correspond with one another, controversies have arisen regarding which method is most accurate. In the search for a single gestational age "gold standard," the potentially valuable information that these alternative measures may provide when used in combination should not be overlooked.