About Birth Control Injections
Summary
Depo-Provera is a progestin-only contraceptive injection that contains medroxyprogesterone acetate (MPA). It works by suppressing ovulation, thickening cervical mucus, and thinning the uterine lining. Two formulations are available: an intramuscular (IM) injection and a subcutaneous (SQ) injection.
Depo-Provera is a birth control shot that contains a synthetic form of progesterone called medroxyprogesterone acetate. It is given every three months and prevents pregnancy by stopping the ovaries from releasing an egg, thickening cervical mucus to block sperm, and thinning the lining of the uterus. The shot is available as either a muscle injection (Depo-Provera CI) or a lower-dose injection under the skin (Depo-SubQ Provera 104). Both are highly effective and do not contain estrogen.
Why a Patient Might Choose This Method
A patient may choose the Depo-Provera injection if they want a highly effective, long-acting birth control method that does not require daily, weekly, or monthly attention. Each injection provides pregnancy protection for approximately three months, making it a convenient option for those who may have difficulty remembering pills, patches, or rings. Depo-Provera does not contain estrogen, making it suitable for some patients who cannot use estrogen-containing contraceptives. Many users also experience lighter periods or stop having periods altogether after several injections.
How It Is Used
Depo-Provera is administered as an injection every 12–13 weeks (approximately every 3 months). Depending on the formulation, the injection is given either into a muscle (intramuscular) or just under the skin (subcutaneous). To maintain effective pregnancy prevention, it is important to receive each injection on schedule. Unlike pills, patches, or rings, there is no daily, weekly, or monthly action required between doses. Some patients may experience irregular bleeding during the first several months of use, but many eventually have lighter periods or stop having periods altogether. Fertility typically returns after the medication wears off, although this may take several months after the last injection.
Options and Comparisons
Depo-Provera is available in two formulations that contain the same active medication but differ in dose and method of administration. Both provide approximately three months of contraception with each injection.
| Product | Active Ingredient | Route | Dose | Frequency |
|---|---|---|---|---|
| Depo-Provera CI | Medroxyprogesterone Acetate | Intramuscular (IM) | 150 mg | Every 12–13 weeks |
| Depo-SubQ Provera 104 | Medroxyprogesterone Acetate | Subcutaneous (SQ) | 104 mg | Every 12–13 weeks |
Depo-Provera CI (Intramuscular)
How It Is Administered
- Given as a deep intramuscular injection into the:
- Deltoid (upper arm), or
- Gluteal (buttock) muscle
- Administered by a healthcare professional
- Given every 12–13 weeks
Both formulations contain the same medication (medroxyprogesterone acetate) and provide essentially the same contraceptive benefits and side-effect profile. The primary differences are the route of administration (muscle vs. under the skin), needle size, dose, and potential for self-administration with the subcutaneous formulation.
The main advantage of Depo 104 SQ over Depo CI IM is that the SQ injection can be delivered to your home and self-administered, you don’t need to have a healthcare professional perform the injection. Otherwise, there are basically the same.
Depo-SubQ Provera 104 (Subcutaneous)
How It Is Administered
- Given as a subcutaneous injection (under the skin)
- Common injection sites:
- Abdomen
- Front of thigh
- Given every 12–13 weeks
- May be administered by a healthcare professional and, in some settings, may be appropriate for self-administration after training
Common Side Effects of Both Formulations
- Irregular bleeding or spotting
- Amenorrhea (absence of periods)
- Weight gain
- Headache
- Breast tenderness
- Mood changes
- Decreased bone mineral density with prolonged use
Advantages Compared
| Advantage | Depo-Provera CI (IM) | Depo-SubQ Provera 104 (SQ) |
|---|---|---|
| Long-acting (3 months) | ✓ | ✓ |
| Highly effective | ✓ | ✓ |
| Estrogen-free | ✓ | ✓ |
| May reduce heavy bleeding and menstrual pain | ✓ | ✓ |
| Many users develop amenorrhea (no periods) | ✓ | ✓ |
| Extensive long-term clinical experience | ✓ | ✓ |
| Smaller needle | — | ✓ |
| Potential for home/self-administration | — | ✓ |
| Often perceived as less painful | — | ✓ |
| Lower hormone dose | — | ✓ |
Potential Disadvantages Compared
| Disadvantage | Depo-Provera CI (IM) | Depo-SubQ Provera 104 (SQ) |
|---|---|---|
| Irregular bleeding or spotting | ✓ | ✓ |
| Weight gain | ✓ | ✓ |
| Delayed return to fertility after stopping | ✓ | ✓ |
| Reversible bone mineral density loss | ✓ | ✓ |
| Mood changes/headaches possible | ✓ | ✓ |
| Requires repeat injections every 3 months | ✓ | ✓ |
| Requires office visit in most cases | ✓ | Less often |
| Larger needle and deeper injection | ✓ | — |
| Injection-site reactions (redness, bumps) | Less common | More common |
Quick Decision Guide
| If You Want… | Recommended Option |
|---|---|
| A traditional clinic-administered injection | Depo-Provera CI (IM) |
| The most established formulation with decades of use | Depo-Provera CI (IM) |
| The smallest needle possible | Depo-SubQ Provera 104 (SQ) |
| The possibility of self-administration at home | Depo-SubQ Provera 104 (SQ) |
| A lower hormone dose with similar effectiveness | Depo-SubQ Provera 104 (SQ) |
Clinical Pearl
Because fertility may take several months to return after stopping Depo-Provera, patients who plan to become pregnant in the near future may want to consider this delay when selecting a contraceptive method.
Ready to discuss birth control options?
Choosing a birth control method can feel overwhelming, but you do not have to sort through the options alone. APNS can help you review your health history, preferences, and goals so you can make an informed decision with guidance from a healthcare provider.