Page created on June 7, 2021. Last updated on January 20, 2022 at 11:19
An intrauterine device (IUD) is form of contraception which is inserted into the uterus. It is small and T-shaped so that it’s stuck in place.
It’s very widely used worldwide due to the many benefits:
- One-time procedure which is effective for 3, 5 or 10 years
- Highly effective (> 99%)
- Highly cost effective
- Does not require regular adherence
- It’s rapidly reversible (fertility returns in a few months)
- There are few contraindications
- There are few side effects
- They don’t contain oestrogen
- They may decrease the risk of cervical, endometrial, and ovarian cancers
- They’re the most effective form of emergency contraception
There are two major types of IUD, one nonhormonal and one hormonal. They have some contraceptive effects in common and some that are different.
Both types have the following contraceptive effects:
- Chronic sterile inflammation of the endometrium due to the foreign body, which is toxic to sperm and egg and impairs implantation
- Thinning of the endometrium, which inhibits implantation
Copper (nonhormonal) IUD
The nonhormonal IUD contains copper. Copper enhances the cytotoxic inflammatory response in the endometrium, it impairs sperm migration, viability, and the acrosomal reaction.
The copper IUD can remain in place for 10 years, and perhaps even longer.
Advantages over hormonal IUD:
- Can be used as emergency contraception (within 5 days)
- Normal menstrual cycle
- Can be used for longer
Disadvantages over hormonal IUD:
- Does not protect against upper genital tract infection (PID)
- Causes heavier bleeding
- Causes more painful menstruation
The hormonal IUD contains levonorgestrel, a progestin. Levonorgestrel thickens the cervical mucus, which acts as a barrier for the sperm. It also causes endometrial decidualisation and glandular atrophy, which impair implantation. The most common types are the Mirena (higher dose) and Kyleena (lower dose).
The hormonal IUD can remain in place for 3 or 5 years, depending on the type.
Advantages over copper IUD:
- Causes lighter bleeding, irregular bleeding, and/or amenorrhoea
- Reduces dysmenorrhoea
- Protects against upper genital tract infection (PID)
- Slightly higher efficacy
Disadvantages over copper IUD:
- Higher risk of ectopic pregnancy
IUDs are good choices for those who:
- Want long-term yet reversible contraception
- Want or need to avoid oestrogen and/or progesterone exposure
They’re not a good choice in those who plan a pregnancy in the following years.
In Hungary, IUDs are generally not placed in women who are nulliparous. Nulliparous women may have more pain on insertion but there’s nothing to indicate that nulliparous women shouldn’t be able to choose IUDs.
- Pelvic inflammatory disease in the last 3 months
- Previous ectopic pregnancy
- Severe distortion of the uterine cavity (congenital, fibroids)
- Sexually transmitted infection
- Pelvic surgery
Other indications for hormonal IUD besides contraception
- Endometrial hyperplasia
- As part of postmenopausal hormonal therapy
Mostly Mirena is used on these indications (as it has the highest dose of levonorgestrel).
Pregnancy must be ruled out first. The physician also rules out any genital infection by a physical examination.
The physician uses a speculum to hold the vagina open. The cervix and anterior and posterior fornixes of the vagina are disinfected. The cervix is then stabilised with the help of a tenaculum.
The length and direction of the cervix and uterus must be measured. This is done to reduce the risk of perforation. The length is measured with the help of a tool called a sound.
The IUD comes pre-packaged in a special tube. The tube is inserted into the uterus, and the IUD is released from the tube. At this point the arms of the IUD will open, giving it the T-shape.
All IUDs have strings attached to them to allow for easy removal. The strings will be cut so that they stick out only a few cm out of the cervix, but they’re still long enough to be used to remove it later.
Complications are rare but can happen:
- Expulsion – the IUD slips out
- Perforation through the uterus
- Pelvic inflammatory disease
Perforation most frequently occurs at the time of insertion. The risk for PID is the highest in the first months.