Most women who use DMPA experience menstrual changes. Some
have prolonged or heavy bleeding, others have irregular bleeding
and spotting throughout the cycle, and many eventually become
amenorrheic. This slide shows the typical pattern of menstrual
changes over the first two years of DMPA use.
After the first DMPA injection, over 40% of users experience
prolonged or irregular bleeding. Following subsequent injections,
these bleeding changes become less common, and after the first
year of DMPA use, they are relatively uncommon.
In contrast, infrequent bleeding and amenorrhea become more
common as the duration of DMPA use increases. Amenorrhea is
a normal response to the progestin in DMPA, which causes the
endometrium to become thin, resulting in little or no menstrual
bleeding. Nearly half of women are amenorrheic after one year
of DMPA use, and about 80% are amenorrheic after two years of
use. After women stop using DMPA, normal menses return.