Birth control pills and intrauterine devices are common forms of contraception. When choosing between them, there are important factors to consider.

Some methods are better for certain people, and a person must be careful when switching between the two.

Intrauterine devices (IUDs) are long-acting forms of birth control that are placed into the uterus. They might contain a synthetic progestin hormone, or be hormone-free and made of copper. A doctor or nurse implants the device in a quick procedure.

The birth control pill usually contains a combination of progestin and estrogen. These sex hormones trigger changes in the ovaries that prevent the release of eggs. They also cause the cervical mucus to thicken, which helps to block sperm entry into the uterus.

Over 14 percent of women worldwide use intrauterine contraception, but use varies wildly between countries. It is essential to understand how to use these methods safely and effectively.

Read on to learn whether the pill or an IUD might be the best choice.

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Choosing the right method of birth control involves a number of factors.

While both IUDs and birth control pills help to prevent unwanted pregnancies, there are many differences between the two.

This section compares the effectiveness, risks, recommended duration of use, and costs of these two contraceptives, as well as a few other considerations.

The best solution when choosing a preferred method of birth control is to speak to a doctor.

However, it is worth bearing the following points in mind.


When taken correctly, the birth control pill is highly effective. It has a success rate of around 99 percent.

The likelihood of becoming pregnant increases if a person takes the pill incorrectly. Around nine in every 100 people who are taking the pill become pregnant, possibly due to incorrect use. It is essential to follow the advice of a doctor when taking the pill.

IUDs are highly effective. Those that release progestin or are copper each have a remarkably low failure rate of less than 1 in 100 during use.

An IUD can remain effective for up to 3-10 years depending on which IUD a person chooses to have placed.

Side effects and risks

Side effects of the birth control pill include:

Many side effects tend to resolve after the first few months of use.

Doctors should assess a person’s risk of vascular disease before prescribing oral contraception. This is especially necessary for people older than 35 years or who smoke. Birth control pills can increase the risk of vascular diseases, such as heart attack and stroke.

They can also increase the risk of blood clots, and rarely, liver tumors Smoking or having high blood pressure or diabetes can further increase these risks.

The pill can also cause rare but severe side effects, so it is important for a doctor to regularly check how the body is responding to the medication.

IUDs can cause some similar side effects.

Common side effects of IUDs include:

  • cramps
  • nausea
  • bloating
  • a backache
  • vaginal discharge
  • irregular bleeding patterns

Rarely, IUDs can also cause serious side effects, including infections.

In the first few weeks, people using IUDs face a slightly increased risk of pelvic infection, though it is overall quite low. Attending checkups regularly can help to ensure that a doctor spots signs of infection.

IUDs can also slip out of place and be expelled from the uterus. This does not occur often but is more common soon after placement.

Never try to put an IUD back into place. Contact a doctor as soon as possible, and they can correctly reinsert the device.

An IUD can also perforate the uterus or cervix, though this is extremely rare. This can cause pain, but there are often no other symptoms. In rare cases, a doctor must remove the IUD surgically.

Duration of use

For most birth control pills to be effective, a person has to take them every day of their 21- or 28-day menstrual cycle. It can be easy to forget to take the pill, and this reduces its effectiveness.

Once a doctor has inserted an IUD, it can remain effective for up to 3-10 years depending on the type of IUD. A person usually only needs to attend regular check-ups to ensure that the device has remained functional and in place.


For people in the US, the pill might cost up to $50 a month, depending on a person’s insurance coverage. Some generic brands cost less than $10 per month. For some people with insurance coverage, it is free.

It might cost nothing or as much as $1,000 to have an IUD, depending on insurance coverage.

Anyone considering an IUD must also factor in the cost of attending regular check-ups to ensure that the placement of the device is correct.

Insurance policies will only cover the cost of the pill or an IUDs in some circumstances. For more information, check policy documentation or speak with a customer services representative.

Special considerations

Factors involving a person’s medical history, lifestyle, and anatomy can make one method of contraception a better choice. When deciding between the pill or an IUD, consider the following:

  • People over the age of 35 years might benefit more from an IUD, due to the risks of blood clots associated with the pill at this stage of life.
  • Doctors tend to warn people who partake in heavy tobacco use against taking the pill due to the combined risk of vascular disease, especially if they also have other risk factors.
  • People who are especially sensitive to hormones might benefit from non-hormonal methods of contraception, such as a copper IUD.
  • IUDs might not work correctly in people with irregular uterine cavities, including people with uterine fibroids.
  • People should avoid using an IUD if they have a current pelvic inflammatory disease, acute liver disease, or current genital tract infections.
  • Anyone with copper allergies should avoid using the copper-based IUD.

The birth control pill is a type of medication that a person regularly takes to prevent pregnancy. A person might refer to it simply as “the pill” or an oral contraceptive.

Birth control pills use hormones to prevent pregnancy. Hormones are chemical messengers. The body produces some to control its functions, while others are produced synthetically.

The two hormones used in birth control pills are estrogen and progestin. The ovaries produce estrogen, but progestin is a synthetic form of progesterone.

Birth control pills typically contain both hormones. Some contain only progestin, but a person usually only takes these while breastfeeding.

When a person takes the pill, the added hormones cause two key changes. They work to keep the eggs from leaving the ovaries during ovulation.

They also thicken the mucus in the cervix to prevent the sperm from reaching the uterus.

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Different types of IUD are available.

An IUD is a small, typically plastic device that contains copper or a form of progestin. These are placed into the uterus.

The design of the device can vary, but most IUDs have two threads that pass through the opening of the cervix into the vagina.

These strings allow a person to check the placement of their IUD, as well as can be seen by a doctor for checkups and later IUD removal.

An IUD works by keeping the sperm from reaching an egg. The progestin IUD thickens the mucus in the cervix, which acts as a barrier to sperm.

The copper IUD causes inflammation in the uterus, which destroys the sperm that enter. IUDs also make it difficult for eggs to stick to the lining of the uterus, preventing implantation.

There are no IUDs available that release estrogen. The copper IUD does not release the copper. Instead, the presence of the copper gives the contraceptive effect.

When switching between contraceptive methods, it is important to leave no gap in coverage. This keeps the risk of becoming pregnant to a minimum.

A person switching from an IUD to an oral contraceptive should begin taking the pill 7 days before the removal of the IUD.

If a person is switching from the pill to a hormonal IUD, a doctor should insert the device 7 days before the final pill.

If a person is switching to a copper IUD, a doctor can insert the device up to 5 days after the last pill without a gap in coverage.

If overlapping with a prior method is not possible, your doctor will advise you to use a backup form of contraception for a certain number of days until the IUD takes effect.

IUDs and oral contraceptives are just two of many options. A person should consider comfort as well as safety and effectiveness when choosing a form of birth control.

Other methods of contraception include:

  • condoms
  • progestin implants
  • progestin shots
  • vaginal rings
  • cervical caps
  • hormonal patches
  • diaphragms
  • sponges
  • abstinence
  • fertility awareness
  • permanent sterilization

For each method of birth control, there are important considerations to take into account.


How do I choose between the pill and an IUD?


It is important to talk with your doctor to confirm that you are medically able to use either method. I would then consider whether you have a good memory for taking pills daily or if you feel you might forget.

Taking the pills daily is important for making sure they work.

The pills will generally give people regular, predictable periods, if used correctly, while periods on the IUDs can be more variable. However, the efficacy and ease of use of the IUD is greater than the pill.

You and your doctor should discuss the pros and cons of each method related to your health status.

Holly Ernst, PA-C Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.
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