<qa>  How long will each transfusion cycle last?Participants will complete daily questionnaires through an automated telephone system to assess pain levels during three blood transfusion cycles. Each transfusion cycle will last between 2 to 4 weeks, depending on the individual needs of the participant, and the cycles will be separated by at least 3 months but no more than 4 months. Prior to each transfusion cycle, study researchers will review participants medical records for certain blood level measurements. 