be explored. The costs to infants, their families, and society as a whole are too high to continue to ignore this lack of knowledge.
The use of caution with the terms used and attention to their definitions is essential in efforts to understand the causes and consequences of preterm birth. It is important to recognize the limitations and variations in the data collected and entered into large administrative and research public health databases. Every effort should be made to improve the quality of national vital records, especially data on the gestational ages of newborns and the rates of preterm births. Uniform data collection and reporting procedures facilitate comparisons among states, over time, and with data from other countries.
The impact of early dating of gestational age by ultrasound on clinical factors such as labor, tocolysis, administration of steroids, timing of elective induction of labor, determination of the mode of delivery, in utero transport, delivery room resuscitation, and determination of adequacy of fetal growth should be evaluated. Professional societies should encourage the routine use of early (before 20 weeks gestation) ultrasound for the establishment of gestational age. Standards of practice and recommendations for training of personnel to improve the reliability and the quality of ultrasound data should be established.