Recommended Dose for Intramuscular (IM) Depo Medroxyprogesterone Acetate (DMPA)
The recommended dose for intramuscular (IM) depo medroxyprogesterone acetate (DMPA) is 150 mg administered by deep IM injection every 3 months (13 weeks) in the gluteal or deltoid muscle. 1
Administration Guidelines
- The 1 mL vial or prefilled syringe should be vigorously shaken just before use to ensure uniform suspension 1
- DMPA can be administered up to 2 weeks late (15 weeks from the last injection) without requiring additional contraceptive protection 2
- Many healthcare providers schedule visits every 11-12 weeks for adolescents to allow for missed or delayed visits 2
- The first injection must be given only during the first 5 days of a normal menstrual period, within the first 5 days postpartum if not breastfeeding, or at the sixth postpartum week if exclusively breastfeeding 1
Efficacy and Mechanism
- DMPA is highly effective with a first-year pregnancy rate of approximately 6% with typical use 2
- After injection, MPA is detected in serum within 30 minutes and plateaus at about 1.0 ng/mL for about three months 3
- Ovulation is inhibited as long as MPA levels remain above 0.1 ng/mL, which can persist for up to 9 months after a single injection 3
- DMPA works through multiple mechanisms including inhibition of ovulation, thickening of cervical mucus, and causing endometrial atrophy 3
Formulation Options
- Two formulations of DMPA are available:
- Both formulations have similar effectiveness and side effects 2
- DMPA-SC can be self-administered, which may improve contraceptive access and reproductive autonomy 2
Common Side Effects and Management
- Menstrual irregularities occur in nearly all patients initially but typically improve over time 2, 4
- Weight gain may occur, with studies showing that weight gain status at 6 months is a strong predictor of future excessive weight gain 2, 4
- DMPA causes reductions in bone mineral density (BMD), which prompted an FDA black box warning in 2004 4
- All patients should be counseled about measures to promote skeletal health, including daily intake of 1300 mg of calcium and 600 IU of vitamin D and regular weight-bearing exercise 2, 4
Long-Term Use Considerations
- Despite the FDA black box warning about BMD loss, ACOG does not advise limiting DMPA use to 2 years or routinely monitoring bone density after that timeframe 4
- Substantial recovery of BMD occurs after discontinuation of DMPA 4
- Return to fertility may be delayed for 9-18 months after discontinuation 5, 6
Special Considerations
- DMPA can be initiated on the same day as the visit ("quick start") if the provider is reasonably certain the patient is not pregnant 2
- When starting DMPA, patients should be counseled to use a backup method (e.g., condoms or abstinence) for at least the first week for contraceptive efficacy 2
- Pre-use counseling about expected menstrual changes is essential to minimize discontinuation rates 7
Common Pitfalls to Avoid
- Failing to shake the vial/syringe vigorously before administration, which can result in inadequate dosing 1
- Not counseling patients about expected menstrual changes, which may lead to unnecessary discontinuation 2, 7
- Overlooking the need for calcium and vitamin D supplementation in long-term users 2, 4
- Unnecessarily limiting DMPA use to 2 years due to BMD concerns when the benefits of preventing unwanted pregnancy often outweigh these risks 4