Fewer Sickle-Cell Crises
Sickle-cell disease is caused by a defect in the structure
of hemoglobin that leads to deformation of red blood cells into a
sickle shape when deprived of oxygen. These cells block blood
flow, causing painful sickle-cell crises. Sickle-cell disease is
most common among blacks and causes at least 80,000 deaths
worldwide every year (231).
Testosterone, progesterone, and progestins such as DMPA
prevent sickle-cell crises, probably by stabilizing the membrane
of red blood cells (139). In the only study of DMPA and
sickle-cell disease, women using DMPA in a 2-year trial had
significantly fewer crises than women given a placebo.
Hematological tests found significant increases in total
hemoglobin and red cell counts among DMPA users and significant
decreases in the level of irreversibly sickled cells (65).
