Understanding the Antara Injection (DMPA)
The Antara injection is a form of hormonal birth control available for free in India's public health system [1.4.1]. The active ingredient is Depot Medroxyprogesterone Acetate (DMPA), a progestin-only contraceptive administered as an intramuscular injection every three months [1.4.7, 1.6.2]. It primarily works by preventing ovulation and thickening cervical mucus to block sperm [1.4.3]. While it has a very low failure rate of around 0.3% with perfect use, it comes with a range of side effects and disadvantages that lead to a high discontinuation rate among users [1.4.7, 1.4.1].
It's important to note that while there is an oral medication for cholesterol also named Antara (Fenofibrate), this article focuses exclusively on the contraceptive injection known by this name in India [1.2.7, 1.4.1].
Significant Disadvantages and Side Effects
The decision to use Antara requires weighing its convenience against its potential drawbacks. The most cited reasons for stopping the injection are related to its side effects [1.4.1].
Menstrual Irregularities
This is the most common side effect associated with DMPA [1.6.8]. Nearly all users experience changes to their menstrual cycle, which can include [1.2.1, 1.4.1, 1.6.5]:
- Irregular Bleeding and Spotting: Unpredictable bleeding between periods is very common, especially during the first few months [1.6.7].
- Amenorrhea: After one year of use, about 55% of women report their periods stop completely. This increases to 68% by the two-year mark [1.6.3]. While some may see this as a benefit, for others it can be a source of concern [1.2.6].
- Prolonged or Heavy Bleeding: Some users may experience bleeding that is heavier or lasts longer than usual [1.2.6].
Delayed Return to Fertility
Unlike many other contraceptive methods, fertility does not return immediately after stopping Antara injections [1.2.6]. It can take an average of 10 months to conceive after the last shot, with a range of 4 to 31 months [1.6.3]. This delay is a significant disadvantage for women who plan to become pregnant soon after discontinuing contraception [1.2.4].
Loss of Bone Mineral Density (BMD)
Long-term use of DMPA is associated with a significant loss of bone mineral density [1.6.3]. This has prompted the U.S. FDA to place a "black box warning" on the medication, recommending its use be limited to two years unless other methods are inadequate [1.6.2, 1.6.3].
- The bone loss is due to reduced serum estrogen levels caused by the medication [1.6.3].
- This is a particular concern for adolescents who are still in a critical period of bone accretion [1.6.3].
- While some bone density may be recovered after stopping the injections, it may not be completely reversible, especially in those who used it for more than two years during adolescence [1.5.1, 1.6.3].
Weight Gain
Weight gain is another frequently reported side effect and a common reason for discontinuing the injection [1.5.2]. Studies have shown that women can gain an average of 5.4 pounds in the first year, and this can increase with longer use [1.6.3]. For example, the average gain was 8.1 lbs after two years and 13.8 lbs after four years [1.6.3].
Other Notable Disadvantages
Beyond the primary issues, users may experience a variety of other side effects [1.5.1, 1.6.1]:
- Mood Changes: Some users report depression, anxiety, or nervousness [1.5.1].
- Reduced Libido: A decreased interest in sex is a possible side effect [1.6.6].
- Common Physical Symptoms: Headaches, dizziness, bloating, acne, and breast tenderness are also reported [1.2.1, 1.5.1].
- Injection Site Reactions: Pain, lumps, or in rare cases, skin dimpling can occur at the injection site [1.2.1, 1.6.7].
- Lack of STI Protection: A critical point is that the Antara injection does not offer any protection against sexually transmitted infections (STIs), including HIV [1.5.3, 1.6.5].
- Increased Risk of Meningioma: A 2024 study noted that prolonged use of Depo-Provera (the same drug as Antara) for more than three years could increase the risk of developing meningioma, a rare type of brain tumor [1.5.4, 1.6.9].
Comparison: Antara (DMPA) vs. Other Contraceptives
| Feature | Antara (DMPA) Injection | Oral Contraceptive Pills | Copper IUD |
|---|---|---|---|
| How it Works | Progestin-only, stops ovulation [1.4.3] | Combination or progestin-only, stops ovulation | Copper ions are toxic to sperm |
| Frequency | Injection every 3 months [1.4.3] | Daily pill | Inserted once, lasts up to 10 years |
| Common Disadvantages | Irregular bleeding, weight gain, delayed fertility [1.2.1] | Must be taken daily, potential for nausea, headaches [1.5.5] | Can cause heavier periods and cramping |
| Return to Fertility | Delayed (average 10 months) [1.6.3] | Usually rapid | Immediate upon removal |
| Bone Density Impact | Potential for significant loss with long-term use [1.6.3] | Generally neutral or slightly protective | No hormonal effects |
| STI Protection | None [1.6.5] | None | None |
Conclusion
The Antara (DMPA) injection is a highly effective and convenient long-acting contraceptive. However, the disadvantages are significant and numerous. The high frequency of menstrual disruption, the potential for considerable weight gain, a notable delay in the return of fertility, and the serious concern of bone mineral density loss with prolonged use are primary drawbacks [1.2.1, 1.6.3, 1.5.2]. Additional side effects like mood changes and headaches also contribute to a high rate of discontinuation [1.4.1]. Any woman considering this method must have a thorough discussion with a healthcare provider to weigh these disadvantages against her personal health profile and family planning goals.
For more information from an authoritative source, you can visit the World Health Organization's page on contraceptive use.
