An intrauterine device (IUD) is a physical contraceptive that sits inside the uterus. IUDs are a highly effective, long term form of birth control.
There are two types of IUD, namely hormonal and nonhormonal. Both types prevent pregnancy by releasing substances into the female reproductive tract. Hormonal IUDs release synthetic hormones, whereas nonhormonal IUDs release tiny amounts of copper.
IUDs can affect a person's period in several ways. Both types of IUD can cause heavy or irregular bleeding immediately after insertion.
Any additional menstrual changes and symptoms a female experiences will depend mainly on the type of IUD. Those who have a hormonal IUD may experience lighter or irregular periods. Those with a copper IUD may experience heavier bleeding than usual.
This article describes how the two types of IUD can affect a person's period. We also provide important information for those who are considering changing birth control methods.
People can experience various changes to their periods depending on the type of IUD they are using.
A hormonal IUD releases a synthetic form of progesterone called levonorgestrel into the uterus.
The presence of levonorgestrel helps to prevent pregnancy. It does this in the following ways:
- Thickening cervical mucus: This makes it difficult for sperm to swim and reach the egg.
- Thinning the endometrium: The endometrium is the lining of the uterus. Ordinarily, this lining must thicken in preparation to receive and nourish a fertilized egg.
- Preventing ovulation: Levonorgestrel may prevent the ovaries from releasing eggs, but it does not do this consistently. The main mechanism of a levonorgestrel IUD is thickening the cervical mucus and thinning the endometrium.
Hormonal IUDs can reduce period symptoms such as long lasting or heavy periods.
Periods occur when the endometrium sheds away and exits the body through the vagina. Because levonorgestrel thins the endometrium, there is less of this material to shed so periods may be lighter and briefer periods.
At present, there are four types of hormonal IUDs available in the United States. They each contain the same kind of hormone but work for different lengths of time:
- Mirena — up to 7 years
- Liletta — up to 7 years
- Kyleena — up to 5 years
- Skyla — up to 3 years
The IUDs that work for the longest contain the largest amounts of levonorgestrel. The higher the levels of this hormone within the IUD, the more likely the user will experience lighter periods or no periods.
Unlike a hormonal IUD, a copper IUD does not prevent ovulation. Copper IUDs work by preventing sperm from reaching and fertilizing an egg.
In the unlikely event that fertilization does occur, the copper IUD prevents the egg from implanting into the endometrium.
Some people may experience heavier bleeding and longer periods with a copper IUD.
Other potential side effects doctors may associate with copper IUDs include:
- bleeding between periods, or spotting
- cramping or aching in the lower back
- irregular periods
Side effects should resolve within 2–3 months of receiving the copper IUD.
With so many variables to account for, it is almost impossible to predict how an individual will respond to a particular IUD.
It can take several weeks or months before the body adjusts to a new IUD. During this adjustment phase, an individual may experience:
- irregular periods
- heavier than usual periods
Adjusting to a hormonal IUD
People can expect lighter bleeding and fewer periods once they adjust to a hormonal IUD. Around 1 in 5 women may have no period at all after the adjustment period.
Adjusting to a copper IUD
Heavy bleeding should decrease about 3 months after receiving a copper IUD.
As copper IUDs do not interrupt ovulation, people can expect to have regular periods.
Both hormonal and copper IUDs can cause unpleasant side effects when a doctor fits an IUD and afterward.
People may experience temporary pain, bleeding, or dizziness immediately after receiving an IUD. People should contact their doctor if these symptoms last longer than 30 minutes.
Some women may find that their body expels or rejects an IUD. In some cases, part of the IUD might dislodge from the uterus, or puncture the uterine wall. If this happens, a doctor needs to remove it as soon as possible.
Although rare, people can become pregnant with an IUD. This can lead to serious health complications, such as ectopic pregnancy and infections.
In general, people who have an IUD should seek medical attention if they experience:
People wishing to change their birth control can discuss their options with a doctor. A doctor will assess the individual's risk of developing adverse side effects. Some factors that the doctor may take into consideration include:
- their medical history
- their current health status
- any medications a person is taking
The risk of having an unintended pregnancy increases when a person switches birth control methods. Doctors try to avoid gaps in protection by overlapping the new contraceptive with a previous birth control method.
People should consider using condoms or some other form of backup contraception until the new birth control takes effect.
IUDs are safe and effective birth control options. IUDs prevent pregnancy by releasing either hormones or a very small amount of copper into the female reproductive system.
People who have a hormonal IUD may experience lighter menstrual bleeding and fewer periods. On the other hand, those who have a copper IUD may experience heavy bleeding during the first few months.
Although rare, it is possible for an individual with an IUD to become pregnant. Anyone who experiences pregnancy symptoms can take a pregnancy test and should contact their doctor immediately. Getting pregnant with an IUD can increase the risk of serious complications.
Anyone considering changing birth control can talk to their doctor. A doctor will often recommend backup contraception until the new birth control takes effect.