An Intrauterine Device (IUD) is a commonly used contraceptive method with a more than 99% success rate. The progestin-containing version of the device has several medical applications with a continuous local hormone release. Despite the numerous advantages of the method, it may sometimes present complications.
Despite the large safety window, IUD use might be associated with several complications, including immediate and late side effects.
Immediate complications occur during and right after the device insertion. The most commonly observed findings are vasovagal symptoms, vaginal bleeding, uterine cramping, and pain.
Complaints associated with chronic side effects include changes in menstrual bleeding, pelvic pain, displacement or expulsion of the device, and failure to protect from pregnancy.
The possibility of pregnancy, especially ectopic pregnancy, should always be considered when relevant symptoms are evaluated.
The most commonly used IUDs are T-shaped copper (Cu-IUD) and levonorgestrel-containing (LNG-IUS) devices. Both methods show similar contraceptive effects, while the progestin content of LNG-IUS is advantageous for additional effects. LNG-IUDs are used in the management of abnormal uterine bleeding and provide endometrial protection in hormone replacement therapy-receiving patients.
How risky is IUD contraception?
IUDs are long-effective contraceptives; LNGs are approved for 3 to 5 years of continuous use, while Cu-IUDs are effective for up to ten years. This extensive period of use increases interest in the question: How risky is it to use an IUD?
Despite the large safety window of IUD use, some women may carry an increased risk with the device placement and use. Younger age, uterine cavity distortions, and reproductive system anomalies are associated with increased complication risks. Uterine position or size, and the length of the endometrial cavity are not scientifically linked to the high complication risk.
Complications associated with IUD contraception
The vasovagal reaction is a collection of symptoms occurring in response to the manipulation of the cervix and uterine cavity, during the device insertion. The reaction is characterized by syncope (fainting), nausea, bradycardia (decreased heart rate), and hypotension. In response to the cervical dilation attempt, women who have never given birth and postmenopausal women may experience hypotension and collapse. Although not recommended for routine use, misoprostol for cervical ripening might be considered to prevent similar experiences.
Although as rare as one in 1000 insertions, the uterus could be perforated, i.e., the instrument might pass through the uterine wall. Lactation is one of the suspected risk factors associated with IUD perforation. According to a study reported from six European countries, women breastfeeding at the time of the IUD insertion carry a six-fold increased perforation risk than the non-breastfeeding users.
Vaginal bleeding, associated with minor traumas and lasting for four to five days on average, may occur in 94% of women immediately following the insertion. However, it should be noted that post-procedure bleeding should not be heavier and longer than usual menstrual bleeding. In most cases, these symptoms resolve spontaneously. However, prophylactic nonsteroidal anti-inflammatory drugs (NSAIDs) might be considered if this condition affects the quality of life.
At the same time, IUD users also should be informed about irregular vaginal bleeding for the first three to six months, including spotting and prolonged or heavy bleeding. 15% of LNG-IUS and 71% of Cu-IUD users experience increased bleeding in the first three months after IUD insertion. Bleeding symptoms decrease in 62% of LNG-IUS and 81% of Cu-IUD users by six months. The progesterone content of LNG-IUS could explain this difference.
Uterine cramping or pain
Women commonly report mild to moderate discomfort or uterine cramping upon IUD placement. Painkillers (NSAIDs) and heating pads are recommended to relieve these symptoms. Furthermore, uterine cramping is reported in 32% of LNG-IUS and 63% of Cu-IUD users three months after the IUD placement.
IUD displacement or malpositioned IUD
Normally, the top horizontal part of the T-shaped device should be located on the uterus's fundus (top pole), with both "arms" of the T directed towards the uterine tubes. Malposition describes the IUD embedded in or protruding through the uterine wall, located within the cervical canal or rotated on its axis. The reported malposition rate is 10%, although the actual incidence is unknown. Regardless of symptoms, IUDs protruding through the uterine wall or displaced into the cervical canal should be removed and replaced if desired.
The device might displace downward immediately following the IUD applicator removal. If recognized, it could be replaced immediately to ensure successful protection. Later, the expulsion of the device (falling out from the uterine cavity) may occur in 2-10% of IUD users. Women younger than 20 years old, diagnosed with large submucosal myoma distorting the uterine anatomy, experiencing dysmenorrhea (painful menstrual cycles), and heavy menstrual bleeding, carry a higher risk of IUD expulsions. Moreover, IUD insertions immediately following the birth or second-trimester abortion are susceptible to expulsion due to the subsequent vaginal bleeding days. Unrecognized expulsions may lead to unintended pregnancies.
Loss of the device
The T-shaped device has a string at the bottom end, which remains outside of the cervical entry and is used to remove the device when needed. The loss of the string raises concerns about the IUD's accidental removal, expulsion, or displacement. Uncommon pregnancy complications and uterine perforation are among the concerning sequences of a missing IUD string.
First, pregnancy should be excluded if the IUD string cannot be visualized. In addition, the emergency contraception method should be recommended until the device is located in the uterine cavity, as the contraceptive effectiveness of the method is questionable at this point. Later, the IUD should be located by X-ray of the abdomen and pelvis if the ultrasound fails to visualize the device.
Partner feeling the string
The string used to manipulate the IUD may sometimes be felt by the partner during sexual intercourse. Generally, the string is trimmed after the insertion adjusted for individual cases. If the partner reports discomfort, the string could be cut further.
The risk of pelvic inflammatory disease (PID) development has been heavily researched. The Contraceptive ‘CHOICE’ Project from the USA analyzed over 9,000 women and reported 1% or below 1% PID risk in IUD users.
Failure to prevent pregnancy
Unintended pregnancy is observed in 0.6% with copper IUD and 0.2% with 19.5mg LNG-IUSs.
One of the risk factors associated with the increased failure is the age younger than 25; women aged 15 to 19 years were found at 30-40% higher risk compared to women between 20-44 years. Other factors are malpositioned IUD or the history of IUD expulsion.
Intrauterine pregnancy with an IUD in place increases maternal and fetal risks. Women are susceptible to infections, including septic abortions and chorioamnionitis. Moreover, having an IUD in place is associated with a 47-57% miscarriage risk, which could be reduced to 20-54% with removal during the early stages of pregnancy. In the later stages of pregnancy, IUDs may present a five-fold increased risk of preterm birth.
Overall, IUD removal should be recommended as early as possible for women interested in the continuation of pregnancy. In the advancing weeks of pregnancy, the IUD string might be lost. In this case, it is not advised to attempt removal.
11-15% of pregnancies are conceived with Cu-IUDs, and 27-53% with LNG-IUS systems are located outside the uterine cavity. If the management of ectopic pregnancy does not include the endometrial cavity, there is no need for removal or replacement of a normally-located IUD, even though it failed once to protect.
Hormonal side effects
Levonorgestrel is a synthetic progestin, and the hormonal content of the LNG-IUS may cause complaints like acne, headache, weight change, and hirsutism. By contrast with common belief, LNG-IUs do not have weight-changing effects compared to Cu-IUDs.
Intrauterine devices are the long-term contraceptive methods with a very high, more than 99%, success rate. The prolonged use is generally considered safe. However, side effects such as abnormal vaginal bleeding, pelvic pain, and contraceptive failure also should be acknowledged and addressed appropriately when occurs.