Injection site skin reactions are common; 8% of users report erythema or irritation at the site.5 In addition, skin changes such as dimpling or lumps at the injection sites have been reported to occur in approximately 1 in 10 users.3 ,6 These may represent a form of lipoatrophy, which is a recognised occurrence with other SC hormonal injections such as insulin and growth hormone.6 Resolution of lesions has been reported,6 but women need to be warned of this cosmetic side effect, as it is likely that this will limit acceptability of DMPA-SC for some.

The commonest reason in the trials for discontinuation was increased or irregular bleeding.

Safety and efficacy Two large Phase III international trials (open, non-comparative) conducted in North and South America and Europe/Asia assessed the 1-year contraceptive efficacy, safety and user satisfaction of DMPA-SC.3 There were no pregnancies observed in over 1700 women and over 16 000 woman-cycles of exposure to DMPA-SC.