Which intrauterine devices (IUDs) are FDA approved?

Updated: Nov 29, 2018
  • Author: Sarah Hagood Milton, MD; Chief Editor: Christine Isaacs, MD  more...
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Three IUDs are approved by the FDA: the 2 levonorgestrel-releasing intrauterine systems (Mirena, approved in 2000 and Skyla, approved in 2013) and the T380A intrauterine copper contraceptive (Paraguard, approved in 1988). Mirena and Skyla contain levonorgestrel (a progestin) that is released for up to 3 years (Skyla) or 5 years (Mirena).

The levonorgestrel-releasing intrauterine systems consist of a T-shaped polyethylene frame with a hormone reservoir that contains 13.5 mg (Skyla) or 52 mg (Mirena) of levonorgestrel. See the image below.

Levonorgestrel-releasing intrauterine system. Levonorgestrel-releasing intrauterine system.

Mirena is initially released at a rate of 20 µg/day and decreases to 11 µg/day after 5 years. [52] The levonorgestrel release results in endometrial suppression and changes in cervical mucus, which deter pregnancy. [55, 56] Skyla releases 13.5 mg of levonorgestrel at a rate of 14 µg/day after 24 days following insertion. The release rate declines to 5 µg/day after 3 years. [15]

Other factors thought to contribute to the contraceptive effect include inhibition of sperm migration, alterations in ovum transport, as well as damage to the ovum. [57] The pregnancy rate at 1 year of use of Mirena is approximately 0.2%, with a cumulative pregnancy rate over 5 years of 0.7%, representing the most effective form of reversible contraception available. [2, 5] The 1-year pregnancy rate with Skyla is 0.4%, with a cumulative pregnancy rate of 0.9% after 3 years of use. [15]

Mirena is FDA approved for contraception for 5 years and Skyla for 3 years, after which time the devices should be removed and replaced if continued contraception is desired. [52] In 2009, Mirena was also approved for treatment of heavy menstrual bleeding in women who have concurrent undesired fertility.

When compared with medical management of menorrhagia with progesterone-containing oral contraceptive pills, Mirena resulted in significantly less menstrual blood loss. Further, women who used Mirena were more satisfied with treatment (76%) compared with women who used oral contraceptive pills (22%). [58] Reid et al studied reduction in menstrual blood loss in women using Mirena compared with women taking mefenamic acid for treatment of menorrhagia. They found that although both significantly decreased blood loss, the effect was more pronounced in the IUD group. [59]

Studies that sought to compare Mirena with endometrial ablation for treatment of menorrhagia found both were equally effective at reducing menstrual blood loss, and there were no significant differences in patient satisfaction between the groups. [60, 61] Mirena is also more cost effective than endometrial ablation. [62] When compared with hysterectomy for treatment of menorrhagia, Mirena was found to be a cost-effective alternative with similar quality of life and patient satisfaction. [63, 64] A Cochrane review published in 2010 summarized and confirmed these results. [65]

The copper T380A IUD is a T-shaped polyethylene frame that is wrapped with a copper wire. See the image below.

Copper T380 IUD and insertion device. Copper T380 IUD and insertion device.

It is approved for contraception for a 10-year interval, after which time it should be removed and a new device inserted. [53] The exact mechanism of action of the copper T380A IUD is unclear, but suggested theories include inhibition of sperm migration and viability, change in transport speed of the ovum, and damage to the ovum. [57] The pregnancy rate in the first year of use is 0.6%, which increases to 1.9% at 10 years of use. [5, 2]

Both the copper T380A IUD and the levonorgestrel-releasing intrauterine system are approved for prevention of pregnancy in women with undesired fertility. The copper T380A IUD is approved for a 10-year interval for contraception. After 10 years, the device should be removed and a new device inserted if the patient desires to continue with the method. [53] Reliable data exists validating that the copper T380IUD is effective for use as an emergency contraceptive if placed within 5 days of unprotected intercourse. [66]

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