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 response to Roosevelt being elected to four terms, the Twenty-second Amendment was adopted six years after the war ended. The amendment bars anyone from being elected president more than twice, or once if that person served more than half of another president's term.