RecruitingPhase 4Biological interventionProphylactic Transfusion In Pregnant in Women With Sickle Cell DiseaseThe goal of this study is to determine if there is a positive effect of prophylactic red blood cell (RBC) transfusion of leukoreduced, ABO, Rh (D/Cc/Ee) and Kell matched blood compared to standard of care on the number of episodes of acute sickle cell disease (SCD) manifestations or pregnancy-related complications requiring acute health care encounters (acute care/ER/Hospital visits) or resulting in death over the entirety of pregnancy until 2 months post-partum in women with SCD. RBC transfusion is the only disease-modifying therapy for pregnant women with SCD, and it is considered a standard treatment option however, there exists no consensus on the role of transfusion therapy in preventing SCD-related pregnancy complications. Participants will be randomly assigned to repeated red blood cell transfusions or the standard of care. Participants will be on study for about 8-10 months (Pregnancy through 2 months post-partum).