percent of individuals in the group (therefore, for copper the RDA is 130 percent of the EAR). The calculated RDA is rounded to the nearest 100 μg.

There are no data for establishing an EAR for pregnancy. Therefore, the EAR was based on estimates of the amount of copper that must be accumulated during pregnancy to account for the fetus and products of pregnancy. The full-term fetus contains about 13.7 mg copper (Widdowson and Dickerson, 1964). The copper content of the fetus is high compared to that of adults due to the high concentration of copper in the liver. In addition to the amount of copper accumulated by the fetus, other products that accumulate copper during pregnancy, including placenta amniotic fluid and maternal tissue, should be considered. The concentration of these tissues is lower, about one-third of the concentration of the fetus; therefore another 4.6 mg is added to 13.7 mg for a total of 18 mg copper. Over the course of pregnancy, this additional requirement is approximately 67 μg/day of absorbed copper or 100 μg/day of dietary copper, a value based on 65 to 70 percent bioavailability and rounding. Evidence suggests that copper absorption may be more efficient during pregnancy, and such efficiency could result in absorption of this amount of copper (Turnlund et al., 1983); therefore no additional increment would be required. However, too few data are available to draw this conclusion. Consequently, an additional 100 μg/day was added to the EARs for adolescent girls and women during pregnancy for EARs of 785 and 800 μg/day, respectively.