What Happens If You Get Pregnant on Birth Control?

You did everything right—took the pill, used protection, followed the rules. So how can a positive pregnancy test still happen? For anyone relying on birth control, discovering a surprise pregnancy can be both confusing and overwhelming.

Understanding what happens in these situations is important for anyone using contraception. This article looks at why pregnancy can happen on birth control, what to do if it occurs, and what to expect moving forward. Readers will find clear information to help them make informed choices and ease their concerns.

Unplanned Pregnancies Happen Frequently

Many people think using birth control or other contraception almost completely prevents pregnancy. While these methods are designed to prevent pregnancy by blocking sperm or changing hormones, there are still chances they may not work as expected. Research shows that about one in five women have faced an accidental pregnancy, even though they were trying to prevent it.

Several reasons may lead to this, such as missing a pill, using hormonal methods incorrectly, or even simple mistakes in family planning. It is important to remember that contraception lowers risk but never removes it entirely. People should not feel embarrassed or ashamed if birth control fails.

Pregnancy Risk with Birth Control Pills

Both combination pills (which have estrogen and progestin) and progestin-only pills (also known as the mini-pill) are popular options for preventing pregnancy. These pills mainly work by stopping ovulation so that the ovaries do not release an egg. They also thicken the cervical mucus, making it harder for sperm to reach an egg.

Oral contraceptives are effective when taken as directed, but they are not foolproof. With typical use, about eight out of 100 people taking either type of birth control pill will get pregnant in a year.

Most pregnancies happen because the pill is not taken on schedule. Missing pills, especially in the first week of a 21-day or 28-day pack, can let estrogen levels drop, which may allow ovulation to occur. For the mini-pill, being more than three hours late increases the risk even more because the hormone level drops quickly.

Other factors can also affect how well the pill works. If someone has vomiting or diarrhea, the body may not absorb the hormones from the pill properly, making it less effective. Certain medicines, like some anti-seizure drugs, can lower hormone levels in the body. Herbal products such as St. John’s Wort might also interfere with how well the pill controls hormone levels.

To lower the chance of pregnancy, it is important to take the hormone pill at the same time each day without missing doses. Paying attention to any health changes, such as stomach illness or starting new medicines, can help make sure the birth control pills work as intended.

When Birth Control Pills Fail

Getting pregnant while on birth control pills can be confusing, especially because the pills can cause changes in periods. Withdrawal bleeding, which many experience during the one-week break from combined pills, may look like a period but is actually a response to hormone changes. Some may have lighter or even no periods due to the continuous use of the pill, making it tricky to spot a missed period as a sign of pregnancy.

Other signs like breast tenderness, nausea, or feeling unusually tired may be easier to notice than changes in your period. Some people also experience mild headaches, mood swings, or dizziness. However, these can be common side effects of the pill itself, which makes it harder to tell if pregnancy is the cause. You might also see changes in your stomach area or develop new acne, which could point to hormone shifts.

If you think you might be pregnant while on the pill, take a home pregnancy test. If the result is positive, stop taking the pill and talk to a healthcare provider. Don’t worry—the hormones in birth control pills taken before knowing you’re pregnant do not harm the baby. The placenta keeps these hormones from reaching the fetus in early pregnancy.

Some health issues and medications—like certain antibiotics or herbal supplements—can reduce the pill’s effectiveness and raise the risk of pregnancy. People with high blood pressure or a family history of blood clots, breast disease, endometrial cancer, or ovarian cysts should get personalized advice from a provider. Health insurance often covers follow-up visits, new prescriptions, and blood pressure checks when stopping the pill.

When stopping birth control pills, some may notice side effects like breast size changes, headaches, mood shifts, or the return of conditions such as anemia or heavy periods. Breastfeeding parents should ask their doctor about safe birth control options. Regular checkups and pelvic exams are important for anyone adjusting their birth control routine.

Pregnancy While Using an IUD

An intrauterine device (IUD) provides a very reliable way to prevent pregnancy. Both copper and hormonal types have low failure rates—copper IUDs fail in about 0.8% of cases, while hormonal IUDs are even less likely to fail at 0.2%. The copper IUD starts working as soon as a provider places it, and the hormonal version becomes effective within five days. Since the IUD stays inside the uterus and doesn’t require any extra steps after insertion, users avoid the risk of forgetting to use it.

However, the body may push out the IUD over time, a process called expulsion. Between three to five percent of IUDs get expelled during five years of use. Signs of expulsion include unexpected heavy bleeding with clots.

If someone notices this, they should check if the IUD string can still be felt. If the string is missing or if there are doubts about the IUD’s position, schedule a check-up with a healthcare provider. In the meantime, use another type of birth control, such as condoms, until a provider confirms the IUD’s placement.

What to Expect if Pregnancy Occurs with an IUD

Although uncommon, pregnancy can occur while using an IUD. With a copper IUD, a missed period is often the first sign. People using a hormonal IUD might find it harder to tell since periods can be very light or even absent. In such cases, symptoms like sudden breast tenderness or nausea might be early signs of pregnancy.

Some people may also feel mild pelvic cramping, which can be confusing—especially if the IUD was recently inserted. Keep an eye out for unusual spotting or unexpected vaginal bleeding, as these may point to a problem. Anyone noticing these symptoms should contact a healthcare provider to check for pregnancy and talk about what to do next.

IUDs and Risks for Ectopic Pregnancy

An IUD works effectively to prevent pregnancy, but in rare cases, someone can become pregnant while using one. When this happens, the likelihood of having an ectopic pregnancy is higher than for someone who becomes pregnant without an IUD.

An ectopic pregnancy happens when a fertilized egg implants outside the uterus, most commonly in the fallopian tube. This condition is a medical emergency because it can be dangerous if not treated quickly.

If a provider suspects ectopic pregnancy, they should perform an ultrasound soon after a positive test. If the pregnancy is not ectopic and continues in the uterus, a provider may remove the IUD if the strings are visible, to reduce other risks like pre-term labor or premature water breaking. However, research shows that an IUD does not lead to an increased risk of fetal abnormalities.

Understanding IUD-Related Risks

When someone becomes pregnant with an IUD, removing the device can slightly increase the risk of miscarriage. Studies are limited, so doctors cannot give an exact number for this risk. Some pregnancies also end early on for reasons not related to the IUD.

If the IUD strings can’t be found, the device might need to stay in place during the pregnancy. In that case, the provider will likely recommend regular ultrasounds to keep track of the IUD’s position—especially to make sure it doesn’t get too close to the amniotic sac, as this could lead to complications.

Pregnancy Risk with the Patch, Ring, or Shot

The patch, vaginal ring, and Depo-Provera shot are common hormonal birth control options. Each works differently and follows its own schedule. With typical use, both the patch and ring have about an 8% failure rate, similar to birth control pills. The Depo-Provera shot is slightly more reliable, with a failure rate of about 6% under typical use.

Consistency is important for these methods to work well. The patch sticks to the skin and should be changed once a week. If it isn’t replaced on time or falls off without being noticed, the risk of pregnancy increases. The vaginal ring is placed inside the vagina and should be replaced once a month. It should not be removed for longer than three hours, as doing so can reduce its effectiveness.

The Depo-Provera shot is given by a healthcare provider every three months. This option may work well for people who prefer not to think about birth control weekly or monthly. But missing a shot or delaying the appointment can raise the chance of pregnancy.

Some medicines, especially those that affect how the birth control pill works, can also reduce the effectiveness of the patch or ring. Anyone taking other medications should talk to a doctor to make sure their birth control will still work as expected.

What to Do If Pregnancy Happens While Using the Patch

Missing a period while using the patch may signal pregnancy. Take a home pregnancy test to find out for sure. If the result is positive, schedule an appointment with a healthcare provider as soon as possible. Do not stop using the patch unless a positive test is confirmed, as this keeps protection consistent in the meantime.

Lowering the Threshold for Pregnancy Tests

When using certain birth control methods like the Depo-Provera shot, periods may stop or become irregular. This can make it tough for someone to recognize early signs of pregnancy since missing a period is not a reliable sign.

Individuals using barrier methods such as male or female condoms, diaphragms, cervical caps, and contraceptive sponges should also be aware that no method offers 100% protection. The same applies to individuals relying on spermicide, fertility awareness-based methods, or the lactational amenorrhea method.

If there are any signs or doubts—like unusual symptoms or condom failure—it is wise to perform a pregnancy test sooner rather than later. Emergency contraceptive pills (morning-after pill) can help prevent pregnancy if taken quickly after unprotected sex, but they are not foolproof.

Regular STI testing, especially when using non-permanent options, is recommended since barrier methods like condoms offer protection from both pregnancy and sexually transmitted infections (STIs), including HIV and other sexually transmitted diseases (STDs).

Permanent birth control options, such as sterilization or vasectomy, provide the highest level of protection against pregnancy but do not guard against STIs. It is crucial to remember that while contraception is effective, checking for pregnancy with a low threshold is important if there is any uncertainty.

Even with the best birth control methods, no option is perfect. Understanding the risks, recognizing early signs of pregnancy, and knowing when to seek medical advice can make a big difference. Whether you’re using pills, an IUD, the patch, or another method, staying informed helps you take control of your reproductive health with confidence.