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Key takeaways
Skyla and Mirena are hormonal IUDs that release levonorgestrel to prevent pregnancy, with Skyla approved for 3 years and Mirena for 5-7 years, depending on the usage.
Mirena also has an FDA approval for slowing heavy menstrual bleeding, unlike Skyla, and can be used off-label for easing symptoms of endometriosis.
Both devices share common side effects including pain, cramping, bleeding after placement, and changes in menstrual patterns, but they carry risks like ectopic pregnancy and uterine perforation.
The cost and insurance coverage for Skyla and Mirena vary, with neither typically covered by Medicare but may be covered by some commercial plans, and both are available by prescription only.
Drug overview & main differences | Conditions treated | Efficacy | Insurance coverage and cost comparison | Side effects | Drug interactions | Warnings | FAQ
Skyla and Mirena are intrauterine systems used for contraception. These devices are placed in the female uterus to help prevent pregnancy. They are commonly referred to as IUDs (intrauterine devices). Hormonal IUDs are just one type of contraceptive method. Other forms of birth control include barrier methods (male and female condoms), oral contraceptive pills (OCPs or birth control pills), and spermicides.
IUDs have an interesting history. Dating back to 1909, the first IUDs were very crude. Various formulations of the early devices did not have persistent use due to their association with infection risk, ectopic pregnancy, infertility, and early hysterectomy. Prior to Mirena and Skyla, Paragard was the most common IUD on the market. Mirena came to market in the year 2000 as the first of its shape and kind. Skyla followed in 2013. Both release the contraceptive hormone, levonorgestrel (LNG), though in different amounts. This is why they are referred to as hormonal IUDs. There are non-hormonal IUDs that do not release any hormones such as the copper IUD. There are also other hormonal IUDs on the market such as Kyleena and Liletta. Skyla and Mirena are good hormonal birth control options for patients who are looking for estrogen-free, long-acting birth control.
There are many differences and similarities between Mirena and Skyla detailed below.
What are the main differences between Skyla vs. Mirena
Skyla (levonorgestrel) is a contraceptive method available by prescription only. It is an intrauterine device containing 13.5 mg of levonorgestrel. Once inserted into the uterus, it begins releasing at a rate of 14 mcg/ day for the first 24 days. By one year, the release rate slows to 6 mcg/day. By year three, the rate typically slows to 5 mcg/day. Skyla should be replaced at the end of the third year. Skyla should only be placed by trained healthcare providers. There are multiple mechanisms by which Skyla prevents pregnancy. First, it causes a thickening of the cervical mucus which inhibits sperm passage to the cervix. It also inhibits sperm motility and function. Finally, this method of birth control alters the endometrium (the lining of the uterus).
Mirena (levonorgestrel) is also a contraceptive device only available by prescription and can be used to prevent pregnancy for up to five years. Mirena also carries an additional approval by the Food and Drug Administration (FDA) to be used to slow heavy menstrual bleeding (menstrual periods). When used for this purpose, it can remain inserted for up to seven years. Like Skyla, it should only be inserted by a trained healthcare professional.
Mirena contains 52 mg of levonorgestrel in each device. Initially, Mirena releases 20 mcg a day for approximately three months. From there it declines to 18 mcg/day after one year, 10 mcg/day after five years, and 8 mcg/day after seven years. It should be removed and replaced after five years for pregnancy prevention, or removed and replaced after seven years if utilized to slow heavy menstrual bleeding. Skyla and Mirena share common mechanisms of action.
| Main differences between Skyla and Mirena | ||
|---|---|---|
| Skyla | Mirena | |
| Drug class | Intrauterine contraceptives | Intrauterine contraceptives |
| Brand/generic status | Brand only | Brand only |
| What is the generic name? | Levonorgestrel | Levonorgestrel |
| What form(s) does the drug come in? | Intrauterine device | Intrauterine device |
| What is the standard dosage? | One device inserted every 3 years | One device inserted every 5-7 years |
| How long is the typical treatment? | 3 years, and can be repeated | 5-7 years and can be repeated |
| Who typically uses the medication? | Adult and adolescent females | Adult and adolescent females |
Conditions treated by Skyla and Mirena
Skyla and Mirena are each a type of intrauterine system used to prevent pregnancy. Mirena also has an approved indication to be used to slow heavy menstrual bleeding. Mirena has been used off-label for endometriosis patients to ease symptoms.
It is important to note that while most emergency contraceptive pills are also composed of levonorgestrel, IUDs are not to be used as a type of emergency contraception.
| Condition | Skyla | Mirena |
| Pregnancy prevention | Yes | Yes |
| Menorrhagia | No | Yes |
| Endometriosis | No | Off-label |
Is Skyla or Mirena more effective?
Skyla and Mirena were studied in thousands of subjects in clinical trials prior to coming to market. The manufacturers of Skyla report a 0.9% pregnancy rate and therefore a 99.1% success rate of preventing pregnancy when used as intended. The manufacturers of Mirena report a 0.7% pregnancy rate and therefore a 99.3% success rate of preventing pregnancy.
When considering Mirena to treat menorrhagia, there are comparisons of it to hysterectomy or endometrial ablation. One systematic review suggests that satisfaction overall is higher with hysterectomy. However, Mirena is more cost-effective than either option, and may be a good first choice when considering the other methods are much more invasive.
This is not intended to be medical advice. Only your doctor can help you decide what is best for you.
Coverage and cost comparison of Skyla vs. Mirena
Skyla is a prescription-only device that is typically not covered by Medicare. It is covered by some commercial plans. Commercial plans must have at least one type of hormonal IUD in their coverage formulary, though which one they choose may vary. The average retail price for Skyla is about $1322. A free SingleCare coupon can lower the cost to approximately $872.
Mirena is also a prescription-only device that is typically not covered by Medicare. It is covered by some commercial plans. The out-of-pocket cost for Mirena is about $1300. A Mirena coupon offered by SingleCare can provide a discounted price of $1043.
| Skyla | Mirena | |
| Typically covered by insurance? | Formulary dependent | Formulary dependent |
| Typically covered by Medicare Part D? | No | No |
| Quantity | 1, 13.5 mg vaginal insert | 1, 52 mg vaginal insert |
| Typical Medicare copay | N/A | N/A |
| SingleCare cost | $872-$930 | $1046-$1116 |
Common side effects of Skyla vs. Mirena
The most common possible side effects of both Skyla and Mirena are pain, cramping, and bleeding after placement, changes in menstrual bleeding, missed menstrual cycles, and ovarian cysts. Less common side effects include abdominal pain, acne, headaches, and inflammation of the vaginal area.
Both Skyla and Mirena can cause rare, serious side effects as well including ectopic pregnancy, pelvic infection, other serious infections, pelvic inflammatory disease (PID), and perforation.
| Skyla | Mirena | |||
| Side Effect | Applicable? | Frequency | Applicable? | Frequency |
| Vulvovaginitis | Yes | 20.2% | Yes | 10.5% |
| Ovarian cyst | Yes | 13.2% | Yes | 7.5% |
| Dysmenorrhea | Yes | 8.6% | Yes | 6.4% |
| Increased bleeding | Yes | 7.8% | Yes | 11.9% |
| Breast pain | Yes | 5.3% | Yes | 8.5% |
| Genital/ vaginal discharge | Yes | 4.2% | Yes | 14.9% |
| Device expulsion | Yes | 3.2% | Yes | <5% |
| Abdominal/pelvic
pain |
Yes | 12.7%/6.2% | Yes | 22.6% |
| Nausea | Yes | 5.5% | Yes | <5% |
| Acne | Yes | 13.6% | Yes | 6.8% |
| Alopecia | Yes | 1.2% | Yes | <5% |
| Headache | Yes | 12.4% | Yes | 16.3% |
| Migraine | Yes | 2.3% | Yes | 16.3% |
| Depression | Yes | 3.8% | Yes | 6.4% |
Source: Skyla (DailyMed) Mirena (DailyMed)
Drug interactions of Skyla vs. Mirena
Because the contraceptive effect of hormonal IUDs is mediated by the direct release of levonorgestrel into the uterine cavity, the mechanism is unlikely to be interrupted by drug interactions. Bayer Healthcare Pharmaceuticals, the manufacturer of both Skyla and Mirena, have not done drug-to-drug interaction studies.
Warnings of Skyla and Mirena
Skyla and Mirena both carry a risk of ectopic pregnancy. While the risk is very low, if you suspect you become pregnant while having an IUD in place, you should contact your healthcare provider immediately.
If a woman does become pregnant with an IUD like Skyla or Mirena in place and it isn’t removed immediately, it can lead to sepsis, premature labor, and premature delivery. Unfortunately, there are risks associated with removal including spontaneous abortion.
Cases of Group A Streptococcal sepsis (GAS) have been reported shortly after insertion. This is why aseptic insertion technique by a trained healthcare provider is necessary in order to reduce this risk. GAS can be fatal if not treated quickly.
Women with a history of pelvic inflammatory disease (PID) should not have a hormonal IUD placed unless there has been a case of a successful intrauterine pregnancy.
Perforation or puncturing of the uterus is a risk with Skyla and Mirena. This can lead to migration of the device, perforation of the intestine, and abscesses.
Partial or complete expulsion from the body can occur. If this occurs, the risk of getting pregnant goes up immediately, and not everyone is aware when this happens. This can be confirmed by ultrasound. It should be suspected if you notice an increase in bleeding.
Women with a history of or suspected case of breast cancer should not use any hormonal contraceptives, including hormonal IUDs like Skyla and Mirena. These patients should inquire about birth control options that are hormone-free.
Skyla and Mirena may lead to irregular bleeding or menstrual periods.
Skyla and Mirena will not prevent sexually transmitted infections (STIs) or HIV/AIDS transmisson.
Frequently asked questions about Skyla vs. Mirena
What is Skyla?
Skyla (levonorgestrel) is a hormonal intrauterine device contraceptive method available by prescription only. It contains 13.5 mg of levonorgestrel, and is approved to prevent pregnancy for 3 years.
What is Mirena?
Mirena (levonorgestrel) is a hormonal intrauterine device contraceptive method available by prescription only. It contains 52 mg of levonorgestrel, and is approved to prevent pregnancy for 5 years. It can also be placed for the purpose of slowing menstrual bleeding and is approved to be placed for this purpose for 7 years.
Are Skyla and Mirena the same?
Skyla and Mirena are both hormonal IUDs approved for use in preventing pregnancy. They each release the same hormone, levonorgestrel, but the amount of hormones is not the same and is not released over the same period of time.
Is Skyla or Mirena better?
Skyla prevents pregnancy 99.1% of the time with proper placement. Mirena’s success rate is slightly higher at 99.3%.
Can I use Skyla or Mirena while pregnant?
No, you should not have an IUD placed while you are pregnant. Your healthcare provider is required to check your pregnancy status prior to insertion.
Can I use Skyla or Mirena with alcohol?
It is safe to consume alcohol in moderation while you have a hormonal IUD in place. Side effects like nausea may be compounded by alcohol.
Does Skyla have fewer side effects than Mirena?
Skyla and Mirena have similar side effects, though some are more or less common with each choice.
Does Skyla make you gain weight?
Weight gain is not expected with Skyla, and Bayer does not report this as a side effect. There is little to no systemic absorption of the levonorgestrel to cause weight gain.
What are the side effects of Skyla?
The most common side effects of Skyla are bleeding after placement, changes in menstrual bleeding, missed menstrual cycles, and ovarian cysts.