Updates & Corrections:
In 2013, a small print run of books was printed with errors in the values for the Iodine DRI on page 220. The correct section should be:
Dietary Reference Intake (DRI): 220 micrograms
Iodine is needed in larger amounts in late pregnancy so your baby can make thyroid hormone, required for the nervous system. An iodine deficiency during pregnancy is dangerous, causing birth defects and other serious problems. Use iodized salt to make sure you meet your requirement for iodine; half a teaspoon contains 200 mcg. The WHO recommends 250 mcg iodine daily during pregnancy: the DRI is 220 mcg.