How to Choose the Right Contraceptive Method
How They Work; Pros and Cons
Injection (Depo-Provera)
| Composition- | Depo-medroxyprogesterone acetate |
| Mechanism of Action- | The sustained level of medroxyprogesterone acetate suppresses ovulation in the majority of women. It also renders cervical mucus impenetrable to sperm and induces a thin endometrium (atrophy), which is unsuitable for implantation. |
| Dosage- | 150 mg of Depo-Provera is given intramuscularly every 12 weeks. Depo-Provera should be administered during the first five days of a normal menstrual cycle, in order to avoid inadvertent administration during pregnancy. It may also be given immediately post partum or following pregnancy termination. Contraceptive effectiveness is achieved within 24 hours. |
| Advantages- |
|
| Disadvantages/Side Effects- |
|
| Efficacy- | Depo-Provera is a highly effective form of contraception, with a Pearl Index of 0.3 (failure rate for 100 women using the method for one year). |
| Contraindications/Poor candidates- |
Absolute
Relative
|
| Follow-up- | Every 12-13 weeks for their next injection. |
| Delayed Injection- |
If it has been less than 14 weeks since the last injection, the next injection can be given immediately. If it has been more than 14 weeks since the last injection, confirm that she is not pregnant (do a pregnancy test) and the next DMPA injection may be given if the pregnancy test is negative. Back-up contraception should be used for the next two weeks. If she has been sexually active in the week prior to her appointment, give the DMPA if the pregnancy test is negative. The pregnancy test should be repeated two weeks later to rule out preganancy. There are no teratogenic effects if the injection is given inadvertently during pregnancy. There is no need to wait for a woman's next menstrual cycle to give the repeat injection. |
Further Information
SOGC Media Advisory: New recommendations from national ob/gyn society address Depo-Provera®, bone loss (05/11/06)
SOGC Clinical Practice Guideline: Canadian Contraception Consensus-Update on Depot Medroxyprogesterone Acetate (DMPA)
updated: 05/18/06
Last Modified: September 5, 2006