The IUD (or IUS) is a device that is placed in the uterus in the doctor’s office and stays in for 5 or 10 years depending on the individual product. It is very effective with a low failure rate. The IUD is also quickly reversible. It is ideal for women who have had at least one child and are not at risk for getting sexually transmitted diseases (STDs). In the US there are 2 IUDs available, Mirena and Paragaurd.
The IUD is placed in the uterus through the vagina in the doctor’s office. It is a bit painful going in. It will cause uterine cramping. This can be much worse for women who have not had children before. It only takes a few minutes to place, and for most women the cramping only lasts for a couple of minutes. It stays in the uterus for the life of the IUD or until the woman desires to have it removed. Removal is usually not painful. I have patients return to the office one month after placement to check that placement is correct. It is recommended that the woman check the string herself each month after menses to be sure it has not come out. This is done by placing fingers in the vagina to feel the strings coming out of the cervix.
The mechanism of action for the IUD is to keep the sperm from being able to reach the egg. In the case of the Mirena, ovulation is also inhibited. Some people believe that IUDs work by keeping fertilized eggs from implanting in the uterus, this is not true. In one study it was shown that the number of cycles in which fertalized eggs did not implant was the same for IUDs as in normal menstruating women on no birth control. This study showed that IUDs are not abortifacient.
The Mirena IUD is effective for 5 years and then must be removed, a new one can be placed at the same time if desired. The Mirena IUD releases a small amount of progesterone continuously during the 5 year life of the product. This helps to inhibit ovulation and decrease menstruation. Most women will have lighter, less crampy periods while using Mirena. Some women will stop having periods altogether. Most women like this side effect, but some do not.
The Paragaurd IUD is effective for 10 years and then must be removed. A new one can be placed at the same time if desired. This IUD has no hormone but is still highly effective. This is a great birth control method for women who want reliable contraception without exposure to hormones. The side effect of the Paragaurd is that most women will experience heavier more crampy periods. For most, this increase is mild.
Until recently most doctors would only place IUDs in women who had had at least one child and were in relationships that did not put them at risk for STDs. Some doctors are now relaxing these constrictions. I personally think this is a mistake, but I am probably in the minority opinion. The issue with the IUD in women with no children is twofold. Placing the IUD into a uterus that has never born a child can be very painful. The cramping tends to be much worse and the risk of incorrect placement is higher. If the IUD is placed incorrectly it is possible to create a dangerous situation for the patient. There is also a higher risk that the IUD will be expelled in women who have not yet had children. This increases the failure rate. The second controversial issue involves placing these in women who have more than one sexual partner or who expect to have new partners while the IUD is in place. If a woman gets an STD like gonorrhea or chlamydia with the IUD in place, it is possible she can get very sick. I have personally seen women so sick from this that they needed to spend time in the Intensive Care Unit. For this reason, I only place IUDs in women who are in long term monogamous relationships.
The IUD is an excellent birth control device for many women. It is long acting, reversible, and does not require women to do anything once it is placed. The Paragaurd is an excellent choice for women who do not want any hormone exposure although it does have more side effects than the Mirena. For women who have not yet had children, or for women who are not in a long term monogamous relationship, I recommend the implant instead of the IUD. For women who do not mind a small amount of progesterone, the Mirena is a great choice as it will reduce or even eliminate the menstrual flow.