Other causes of nausea include side effects from medications, pain, pregnancy and morning sickness, seasickness, viral infection, alcohol toxicity, and disease of the brain, esophagus, stomach, gallbladder, liver, pancreas, and intestine.
so roosevelt was able to win more than two terms because there was not yet a formal term limit on the presidency and the unique conditions when he ran for his third and fourth terms made his arguments for breaking with tradition acceptable to a majority of american voters
In 1947, President Harry S. Truman proposed the Hoover Commission which recommended that no president be allowed to serve more than two terms. One of the reasons for such a proposal was that many people felt that allowing more than two terms would lead to a sort of monarchy.