Side Effects (see Managing Any Problems)
Some users report the following:
- Changes in bleeding patterns†, including:
- Lighter bleeding and fewer days of bleeding
- Irregular bleeding
- Infrequent bleeding
- Prolonged bleeding
- No monthly bleeding
- Weight gain
- Breast tenderness
Bleeding changes are normal and not harmful. If a woman finds them bothersome, counseling and support can help.
Known Health Benefits and Health Risks
Long-term studies of monthly injectables are limited, but researchers expect that their health benefits and health risks are similar to those of combined oral contraceptives (see Combined Oral Contraceptives, Health Benefits and Health Risks). There may be some differences in the effects on the liver, however (see Question 2).
† For definitions of bleeding patterns, see “vaginal bleeding.”