Implications of metric conversion

The international scientific community is rapidly achieving conversion to the metric system, and the Système International (SI system) has been chosen for use by health scientists. Because the United States remains 1 of only 4 countries not now using part or all of the SI system, there is now a systematic effort toward rapid conversion. Although most of the SI system is not controversial, several SI units are highly so. Examples include joules instead of calories, pascals instead of millimeters of mercury, and moles per liter instead of milligrams per 100 milliliters. Obstetrician-gynecologists need to be familiar with the SI units and to voice their feelings about the various controversial units. There are decisions still to be made, and the time for discussion and advice is now.