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
His huge success in dealing with the Great Depression and carrying the USA through the Second World War so frightened the Republican Party that they managed to get a Bill through Congress that no president could serve more than two terms. more on this see wiki. Democratic FDR was a Democrat. he was a democrat.