The so-called intrauterine device (IUD) is one of the modern contraceptive methods. The IUD is also called a coil because the prototype was shaped like a spiral ring. To date, more than 30 models have been developed, and most intrauterine devices are copper or hormone-containing. The contraceptive method is reversible and generally effective for a period of 3-5 years, in a few cases 7-10 years. The Pearl index (describing the reliability of a contraceptive measure based on the number of pregnancies that occurred per 1,200 cycles of use or per 100 years of use) is 0.1-1. The mechanism of action varies by IUD model:
- Intrauterine device with copper: this IUD is made of a flexible tissue-friendly material and is T-shaped. The vertical arm is wrapped with copper, which is continuously released into the environment. The effect is based on a foreign body irritation of the endometrium (lining of the uterus) by the copper ions. The result is aseptic (sterile) superficial endometritis (inflammation of the uterus) with increased macrophages and leukocyte infiltration (defense cells of the body). Nidation inhibition (inhibition of implantation of the egg into the mucosa) occurs. In addition, the copper ions have a toxic effect on both the sperm (sperm cells) and the blastocyst (fertilized egg). The different models differ in the size of the copper surface. Some designs have small gold clips that make the IUD more visible in ultrasound. Furthermore, the chemical interaction of copper and gold leads to a longer effectiveness, so that the normal lying time of a copper IUD of 3-5 years can be extended to 7-10 years.
- Progestogen IUD (hormonal IUD, also called intrauterine system (IUS)): This is an intrauterine device that contains the luteal hormone levonorgestrel in the vertical plastic cylinder, which is continuously released into the uterus. Since the substance is released directly into the uterine cavity, only low hormone concentrations are necessary for its contraceptive effect. This means that the amounts absorbed (absorbed into the blood) and therefore the blood levels are very low, and so is the overall side effect rate of the hormone. In addition to foreign body irritation, the effect of the progestin IUD is based on a progestin-induced thickening of the cervical mucus (cervical barrier), so that the sperm are prevented from ascending into the uterus, a reduction in tubal motility – this leads to a disruption in the transport of the egg into the uterine cavity – and inactivation of the sperm. Furthermore, the hormone progestin prevents the endometrium (lining of the uterus) from building up in accordance with the cycle. A possibly fertilized egg cell can then not implant in the mucosa (disturbance of nidation). The reduced mucosal thickness is usually accompanied by a weaker menstrual period (hypomenorrhea), which many women welcome. Occasionally, the period also remains completely absent.
The IUD insertion represents a sensitive procedure that builds on intensive preparation and the experience of the attending physician.
Indications (areas of application)
- When regular use of oral contraceptives (the pill) is not guaranteed.
- In patients who cannot use oral contraceptives, for example, because of a tendency to thrombosis (vascular disease in which a blood clot (thrombus) forms in a vessel).
- In women in the late fertile (fertile) phase, when oral contraceptives should no longer be taken because of age or disease, or to avoid sterilization
- In women who suffer from dysmenorrhea (menstrual pain) or hypermenorrhea (increased menstrual bleeding), the progestogen coil is a particularly suitable method of contraception
Contraindications
IUD insertion is contraindicated if genital infections, changes in the shape of the cavum uteri (uterine cavity), or other conditions are present. These include:
- Salpingitis (inflammation of the fallopian tubes).
- Colpitis – acute or chronic inflammation of the vagina (vagina).
- Endometritis or endomyometritis – inflammation of the endometrium / endometrium including the uterine muscle.
- Uterus myomatosus – benign muscular growths of the uterine wall.
- Uterine hypoplasia – underdeveloped, small, hardy uterus with long cervix.
- Uterus septus – uterus consisting of two uterine cavities.
- Unclear genital bleeding
- Suspected malignant (malignant) disease of the uterus or cervix.
- Pregnancy
The procedure
To avoid complications such as dislocation (incorrect position) or perforation (damage to the wall of the organ), a thorough clinical examination and vaginal sonography (ultrasound procedure in which a probe is inserted into the vagina (sheath), allowing better visualization of the internal genital organs) are performed before IUD insertion. Both measures are used to determine the exact position and size of the uterus (womb) in the pelvis (anteversio: the uterus is tilted forward; anteflexio: the uterus is slightly bent between the cervix uteri and cavum; retroversio: the uterus is tilted backward; retroflexio: the uterus is slightly bent between the cervix and cavum, stretched uterus). Uterine abnormalities (e.g., uterus septus, a uterus with two uterine cavities) or uterus myomatosus (benign muscular growths of the uterine wall) can also be excluded during this examination. In addition, an assessment of the bacterial colonization of the vagina by phase contrast microscopy is useful. Insertion of the intrauterine device takes place under aseptic conditions. The most favorable time is the last day of menstruation, because at this time the cervix and the cervical canal are open, so that the insertion of the IUD is facilitated. In women who have already given birth, the procedure usually succeeds easily. However, the IUD insertion should take place no earlier than 6 weeks post partum (after birth). In addition, during breastfeeding, the reliability of the IUD is reduced. If the cervical canal is too narrow, pretreatment with the prostaglandin derivative misoprostol (2 tablets) can be given the night before to soften the portio (outer cervix). Another aid is careful dilation (widening) with Hegar rods (slightly curved rods made of stainless steel that have a round cross-section and a conical tip. They are used in obstetrics to gently and quickly dilate the cervical canal). Now the applicator is inserted into the cavum uteri (uterine cavity). The IUD is pushed in and unfolds its normal shape intrauterine. The retrieval threads that protrude into the cervical canal are shortened to 2 cm. Under no circumstances should the IUD insertion be performed in the 2nd half of the cycle. The reason for this is that it must be ruled out that an early pregnancy has already occurred. Immediately after the insertion, a sonographic check is performed. Pain: Patients predominantly rate the feeling of the IUD insertion as tolerable. In the majority of cases, they felt either nothing or a mild pulling sensation in the lower abdomen. Approximately 4% of patients reported that the pain was severe or barely tolerable. These patients may be given analgesics (pain relievers) as adjunctive medication. Furthermore, the position of the intrauterine device should be checked after the first menstrual period (at the latest six weeks after insertion) and then at six-monthly intervals. Note: The English Royal College for Obstetricians and Gynecologists recommends that women older than 45 years have an intrauterine device placed, such as a copper or hormonal IUD, and left uterine for seven years or longer.
Potential complications
- Uterine perforation with use of copper-containing and levonorgestrel-containing IUDs; incidence approximately 1 in 1,000 insertionsMain risk factors were (regardless of IUD type):
- Breastfeeding at the time of insertion
- Insertion in the first 36 weeks after a delivery.
- Explusion (expulsion or displacement) – in a maximum of 3 women out of 1,000.
- Infections – esp. in the first 3 weeks after an IUD insertion it can come more frequently to ascending infections (“Pelvic inflammatory disease”, PID) of the genital tract.
Benefit
The intrauterine device is a proven method of contraception. IUD insertion guarantees safe contraception. IUD position control prevents complications during use or after insertion.