Can an IUD affect a positive pregnancy test?

Yes, you can get pregnant while using an IUD — but it’s rare.

IUDs are more than 99 percent effective. This means that less than 1 out of every 100 people who have an IUD will become pregnant.

All IUDs — hormonal, non-hormonal, or copper — have a similar failure rate.

Read on to learn why this happens, your options for emergency contraception, when to take a pregnancy test, and more.

In a small number of people — between 2 and 10 percent — the IUD can slip partly or completely out of the uterus.

If this happens, you can get pregnant. You might not realize the IUD has fallen out of place.

In some cases, pregnancy can happen because the IUD hasn’t started to work.

The copper IUD, Paragard, protects against pregnancy immediately.

But hormonal IUDs, such as Mirena and Skyla, can take up to seven days to become effective. You could get pregnant if you have sex without a condom or other form of protection during this window.

You may also experience IUD failure if the IUD has been in place for longer than the manufacturer recommends.

Although one 2015 study found that Mirena may protect against pregnancy for a full year after its FDA-approved expiration date, more research is needed to confirm this finding.

If you suspect that your IUD has failed, talk to a doctor or other healthcare provider about using emergency contraception (EC).

EC will stop you from ovulating and prevent you from getting pregnant if your IUD has failed. It won’t end a developing pregnancy.

Your provider may recommend one of the following options:

Hormonal pills

As a rule of thumb, hormonal EC is most effective when taken within 72 hours of birth control failure.

However, you can still take hormonal EC for up to five days afterward.

You can purchase EC pills over the counter at your local pharmacy. If you’re insured, you may consider calling your doctor to get a prescription.

EC is considered preventive care, so you may be able to fill your prescription for free.

If you don’t have insurance, you may have access to a financial assistance program.

Copper IUD

If you have a hormonal IUD and suspect that it’s failed, talk to your doctor about switching to a copper IUD.

The copper IUD can prevent pregnancy if it’s inserted within five days of birth control failure.

The copper IUD can be left in for up to 10 years.

As with EC pills, the copper IUD may be available at a reduced rate through your insurance plan.

If you don’t have insurance, you may have access to a financial assistance program. Some birth control clinics will offer services even if you can’t pay.

If the pregnancy develops in your uterus, you may notice typical pregnancy symptoms, such as:

• missed periods
• nausea, possibly with vomiting
• sore, enlarged breasts
• tiredness
• mild cramps
• light spotting

Some of these symptoms — like cramping, spotting, and missed periods —can be similar to the side effects caused by your IUD.

If you don’t know what’s causing your symptoms, see a doctor or other healthcare provider.

Having an IUD in place may be slightly more likely to result in an ectopic pregnancy.

This occurs when the embryo implants outside of your uterus.

Symptoms of an ectopic pregnancy include:

• sharp waves of pain in your abdomen, pelvis, shoulder, or neck
• severe pain on one side of your abdomen
• vaginal spotting or bleeding
• dizziness
• fainting
• rectal pressure

An ectopic pregnancy is considered a medical emergency, so seek immediate medical attention if you’re experiencing any of these symptoms.

If you think you might be pregnant, take a home pregnancy test. These tests are available over the counter (OTC).

You can take an OTC test on the first day of your missed period.

If your IUD has caused your periods to be irregular — or to stop completely — you should wait to one to two weeks after you suspect your IUD failed to take an OTC test.

These tests are almost 99 percent accurate.

In most cases, a negative result means that you aren’t pregnant.

If you’re experiencing unusual symptoms or suspect that the test isn’t accurate, see a doctor.

If the test is positive, make an appointment with an OB-GYN or other healthcare provider. They’ll confirm the results with a urine or blood test and discuss next steps.

Your doctor will first double-check that you’re pregnant with a urine or blood test.

Pregnancy tests check for human chorionic gonadotropin. Your body only produces this hormone when you’re pregnant.

Your doctor will then do a pelvic exam. If your IUD string is visible, your doctor will remove the IUD. If your IUD string isn’t visible, they’ll perform an ultrasound to help locate your IUD. They may need to use a cytobrush or other tool to aid in removal.

Current guidelines suggest that the IUD should be removed before the end of the first trimester. Removing the IUD after this point may result in complications for both the person carrying the pregnancy and the pregnancy itself.

You should have the IUD removed regardless of whether you plan to keep or terminate the pregnancy.

An ultrasound will also help your doctor determine if the pregnancy is healthy or if there are problems, such as ectopic pregnancy.

If it’s ectopic, your doctor will recommend medication or surgery to remove the embryo. The exact treatment depends on the embryo’s location and overall development.

IUD pregnancies are slightly more likely to be ectopic, or occur outside of the uterus. Ectopic pregnancies sometimes form in the fallopian tubes.

If the pregnancy isn’t removed, the tubes can burst and cause life-threatening bleeding.

An ectopic pregnancy that occurs outside of a fallopian tube — in the cervix, for example — is unlikely to grow without endangering your overall health.

Other risks associated with IUD pregnancies include:

• miscarriage, which occurs when the pregnancy ends within the first 20 weeks
• premature delivery, or going into labor before the 37th week of pregnancy
• premature rupture of membranes, which is breaking of the amniotic sac before labor starts
• placental abruption, which is when the placenta partially or completely separates from the uterine wall
• placenta previa, in which the placenta partially or completely covers the opening of the cervix
• pelvic infection
• low birth weight, which occurs when a baby is born at less than 5 pounds, 8 ounces

It’s also possible that exposure to the hormones in certain IUDs could affect the pregnancy.

There have been reports of congenital abnormalities in live births. For example, exposure to increased levels of progestin has been linked to “increased masculinization of the external genitalia” in female fetuses.

You’ll have to terminate the pregnancy if it’s ectopic. An embryo growing outside the uterus can’t survive. There’s also significant risk to the mother’s health in an ectopic pregnancy.

Doctors can terminate the pregnancy in one of two ways.

• If you’re in your first trimester, you can take a medication called methotrexate to stop the embryo from growing. Your body will then absorb the pregnancy tissue.
• If you’re past your first trimester, you’ll undergo a surgical procedure to remove the ectopic pregnancy.

If the pregnancy is in your uterus, you can decide whether you want to have an abortion.

You can take the abortion pill before week 10 of pregnancy. Medical abortion is available at or after week 10 of pregnancy.

Depending on where you live, you’ll need to have the abortion done before your 20th to 24th week of pregnancy. Abortion laws are more restrictive in some states than others.

If you suspect that your IUD has failed, call your doctor or other healthcare provider right away.

You may be able to take Plan-B or another form of EC to prevent pregnancy. If it’s too late to take EC, your provider will administer an in-office test to determine whether you’re pregnant.

Once you know, you and your doctor can discuss your options going forward.