Skip to Content

Intrauterine Devices (IUDs)

Intrauterine devices (IUDs) are T-shaped devices which are placed inside of the uterus to prevent conception. IUDs are the most effective form of birth control and come in two types: copper and hormone-eluting.

What is an IUD?

An intrauterine device or IUD is a type of birth control. IUDs are small T-shaped medical devices which are inserted through the cervix into the uterus.  They prevent conception by making the uterus “inhospitable” to a fertilized egg so that it will not effectively implant in the uterine wall.

While both device types are constructed of plastic, copper IUDs contain a copper (metal) component and hormonal IUDs are made of impregnated plastic which will release a progesterone type hormone over a period of years.

IUDs are not widely used in the U.S. but are highly effective and have a much lower failure rate than other forms of birth control.  They are intended to be left in place for five to 10 years and while they are considered to be safe, some women have experienced severe side effects or complications from both types.

Types of IUDs

There are two basic types of IUDs:  Copper and Hormonal.  Both types are available in the U.S. and in other parts of the world and are considered highly effective.   IUDs are implanted in the uterus and intended to be left for at least five years.  Some IUDs are considered effective for much longer, potentially up to 12 years.  IUDs offer an advantage over other forms and eliminate the need to take pills on a daily basis or use other forms of temporary birth control such as spermicide.  They do not provide protection from sexually transmitted diseases (STD) or infections (STI).

Copper IUDs

Copper IUDs are constructed of a plastic T-shaped device, covered by copper coils.  The copper surrounding the plastic prevents conception by interfering with fertilization by acting as a spermicide and by making the uterus inhospitable to a fertilized egg.

Currently, there is only one copper IUD approved by the Food and Drug Administration.  The ParaGard IUD is effective for 10 years, and in some cases, may be effective for up to 12 years.  Copper IUDs are implanted through the vagina, inserted through the cervix so that the T portion is inside of the uterus.  Copper IUDs can be removed at the 10-year mark or at any time the patient wishes to become pregnant or no longer needs it.

Hormonal IUDs

Also called “progestin” IUDs are constructed of plastic which has been impregnated with a synthetic progesterone hormone, levonorgestrel.  Once implanted, the plastic will “emit” or release the hormone over a period of years.  Progestin or hormonal IUDs work in three ways:

  1. Similar to birth control pills, the hormone in the IUD prevents ovulation so that no egg is produced from the ovaries
  2. The hormone in the IUD also thins the uterine lining so that a fertilized egg cannot attach
  3. The IUD placed in the cervix thickens cervical mucus which blocks or traps sperm

In the U.S., there are four brands of hormonal IUDs which have been approved by the FDA.  They differ mainly in the amount of hormone, how long they last and what company manufactures them.  All of the progestin IUDs can be removed at any time if the woman wishes to become pregnant or for other reasons such as complications but otherwise, must be removed and replaced at the designated time of 3, 4 or 5 years depending on brand.

Of the four products, Mirena has the highest level of hormones, lasts the longest and is the most well-known progestin IUD.  It is also approved to treat heavy menstrual bleeding but has been the subject of numerous adverse event reports and a number of lawsuits.

Mirena’s manufacturer, Bayer, has introduced two lower hormone level products, Kyleena and Skyla.  Allergan also manufactures a hormonal IUD, Liletta which releases hormone at nearly the same rate as Mirena but is intended to last for a shorter period of time.  All three of these products are only approved as contraceptives and not approved to treat heavy menstrual bleeding.

IUD Safety Concerns

Many medical devices have caused a number of safety concerns.  IUDs have been particularly troublesome for some women.  Both copper and hormonal IUD types have caused serious side effects and have been the subject of a number of lawsuits.  In particular, Mirena lawsuits continue to be filed for serious side effects including device migration, unwanted pregnancy with injury and other concerns.

Please See Mirena Side Effects for more information

Certain conditions may increase the likelihood of complications when using an IUD.  Some medical conditions will be considered contraindications or reasons why an IUD should not be inserted.  These include:

  • Sexually transmitted disease or infection (STD, STI)
  • Pelvic infection
  • Pregnancy
  • Uterine, ovarian, or cervical cancer
  • Unexplained vaginal bleeding

The timing of insertion may also be dependent upon time since childbirth or abortion and time of last menstrual period.  In addition, it is important to note that IUD will not provide protection against sexually transmitted disease or infection.  Other prophylactic protection such as condom use may be required.

Back to top