What are intrauterine devices (IUDs)?

Updated: Nov 29, 2018
  • Author: Sarah Hagood Milton, MD; Chief Editor: Christine Isaacs, MD  more...
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Intrauterine devices (IUDs) are highly effective reversible contraceptives. [1] Intrauterine contraception is an increasingly popular choice for women seeking long-term pregnancy prevention. [2] In addition, IUDs are among the most cost-effective options for reversible contraception, and overall patient satisfaction with this method is high. [3, 4]

Three intrauterine devices (IUDs) have been approved by the FDA in the United States: the Mirena intrauterine device, the Skyla intrauterine device, and the ParaGard (T380A intrauterine copper contraceptive). Mirena and Skyla contain levonorgestrel (a progestin) that is released up to 3 years (Skyla) or 5 years (Mirena).

The levonorgestrel-releasing intrauterine systems are the most effective IUD available, with a 0.2% pregnancy rate at 1 year of use for Mirena [1] and a 0.9% pregnancy rate after 2 years of use for Skyla. [5] Each levonorgestrel-releasing intrauterine system consists of a T-shaped polyethylene frame with a hormone reservoir that contains either 52 mg (Mirena) or 13.5 mg (Skyla) of levonorgestrel. Levonorgestrel is initially released at a rate of 20 ug/day and decreases to 11 ug/day after 5 years for Mirena. [6] Skyla releases 13.5 mg of levonorgestrel at a rate of 14 ug/day after 24 days following insertion. The release rate declines to 5 ug/day after 3 years. [5]

The mechanism of action of the levonorgestrel-releasing intrauterine system is thought to be multifactorial. The levonorgestrel is thought to cause endometrial suppression and changes in cervical mucus that render the intrauterine environment inhospitable for pregnancy. [7, 8] In addition, the physical presence of the IUD causes alterations in ovum and sperm migration and potential damage to the fertilized embryo prior to implantation. [9] The most common complaints voiced by women using the levonorgestrel-releasing intrauterine system are irregular spotting, which commonly occurs in the months following placement, amenorrhea, and pain. [9, 10]

The copper T380A IUD is also highly efficacious, with a 0.8% pregnancy rate at one year of use. [1] It consists of a T-shaped polyethylene frame that is wrapped with a copper wire. It is approved for contraception for a 10-year interval, after which time it should be removed and a new device placed. The mechanism of action is thought to be related to the physical presence of the IUD, which interferes with sperm and ovum transport and potentially damages the ovum or the embryo prior to implantation. [9] The most common side effects of Copper T380A IUD use are bleeding and pain. [10]

In general, IUD insertion and removal are both outpatient office procedures intended to be performed by trained health care providers. This objective of this review is to outline IUD removal and discuss issues relevant to this procedure.

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