Many birth control or contraceptive options are available to prevent an unintended pregnancy. Despite one’s best efforts, pregnancy can still occur with the use of contraceptives. Let’s explore the failure rates of different birth control methods, situations that may make them less effective, and the risks of continuing them if you become pregnant.
Becoming pregnant while on birth control is possible.
User error or adherence is the most common cause of birth control failure.
Studies have shown that birth control use in early pregnancy is not associated with birth defects or anomalies.
What is birth control?
Birth control is a medication, device, or method used to prevent a pregnancy before it can begin. Options include:
- Contraceptive pills
- Intrauterine devices (IUDs)
- Condoms and diaphragms
- Natural family planning
- "Pull-out" methods
- Sterilization procedures
Contraception in the United States is commonly used, with an estimated 88% of all people with vaginas aged 15–44 using at least one form of birth control within their lifetime. Choosing a suitable birth control method is highly personal and influenced by your general health, age, future pregnancy plans, effectiveness, and ease of use.
Can you get pregnant while using birth control?
Yes. It is possible to get pregnant while using birth control. Birth control is highly effective at preventing pregnancy. Most unintended pregnancies occur while using contraception are due to user error or adherence.
Multiple studies have concluded that approximately half of the yearly pregnancies in the United States are unplanned. Of these unintended pregnancies, about 43% of pregnancies were conceived while using a contraceptive method that failed due to inconsistent or incorrect use.
We will not discuss birth control methods such as natural family planning, condom/diaphragm use, the “pull-out” method, or sterilization procedures here. This article will focus on the rates and risks of pregnancy occurring while taking hormonal medications or using contraceptive devices because of the potential impact on your health or the dangers of contraceptive methods on your pregnancy.
Failure rates of birth control methods when used correctly
Even if appropriately used, contraception can still have a failure rate, allowing a pregnancy to occur. Below is a table of hormonal contraceptives and their failure rates, even when used as directed:
|Failure rate||Type of contraception||Description|
|0.05%||Implants||Hormone-based implants that are effective for up to three years.|
|0.2–0.8%||Intrauterine devices||Hormonal IUDs are effective for three to eight years, and Copper IUDs (non-hormonal) are effective for up to ten years.|
|6%||Injections||A shot is given once, on time, every three months.|
|9%||Birth control pill||An oral medication is taken at the same time every day.|
|9%||Patch||A hormonal patch that is changed every week to three weeks.|
|9%||Vaginal ring||A ring that releases hormones is changed every month.|
It is important to note that none of the above birth control methods protect against sexually transmitted infections or diseases.
What makes birth control less effective?
Timing becomes imperative with many birth control methods because the release of hormones demands consistency. Appropriate levels of hormones are needed to stop ovulation and avoid pregnancy. Other reasons for failure exist as well. Below are some common reasons for the failure of each contraceptive method.
Implants and IUDs
Implants and IUDs are considered long-acting reversible contraception (LARC) methods, and there is little need for the user to do anything after their implantation to maintain efficacy. Both methods have nearly a 100% success rate if they are placed correctly.
A healthcare provider must administer injections consistently every 12 to 13 weeks. Delaying a dose increases the potential for pregnancy. The only medication that appears to reduce the effectiveness of Depo-Provera (injection) is Cytadren, a drug used in Cushing’s syndrome.
Birth control pills
Medication needs to be taken at the same time every day to suppress ovulation. Missing a pill is common. Missing two pills in a row greatly increases the potential for pregnancy. The last pill should be taken immediately, and a backup barrier method should be used. Commonly used antibiotics and other medications will not diminish the effectiveness of birth control pills. However, substances used to treat tuberculosis, meningitis, HIV, and some anti-seizure drugs can impact the effectiveness of birth control pills.
The transdermal patch must be attached entirely to the skin of your stomach, upper arm, buttock, or back to be effective. Failing to fully adhere to the patch, forgetting to change a patch, or delaying application of a new patch increases the potential for pregnancy.
This clear plastic ring is placed in the vagina and replaced monthly. The ring can be removed for up to three hours without impacting the birth control effect. Any longer and a backup barrier method should be used to decrease the chance of pregnancy.
Early signs of pregnancy
As a person of child-bearing age when pregnancy is possible, being aware of the early signs of pregnancy is a crucial responsibility. Early signs of pregnancy include:
- Missed period
- Increased urination
- Fatigue or feeling tired
- Nausea, with or without vomiting
- Sore breasts
It is important to remember that many contraceptive options may result in shortened or light menstruation, amenorrhea, or no menstruation, which may make detecting or anticipating pregnancy symptoms more difficult. Take a pregnancy test or consult your healthcare provider if you suspect you may be pregnant.
Risks if you become pregnant while using contraception
How might the hormonal effects of birth control impact a developing baby if a pregnancy does occur? According to the American College of Obstetricians and Gynecologists, hormonal birth control cannot cause a miscarriage.
Several studies have concluded that the pill and other forms of hormonal birth control are not associated with significant congenital disabilities in early pregnancy. There are some other risks you may want to be aware of if you find yourself pregnant while using some forms of birth control.
IUD and ectopic pregnancy
The purpose of an IUD is to stop an intrauterine pregnancy. You are more likely to have an ectopic pregnancy with an IUD. Yet, because IUDs are so effective at preventing pregnancy, an ectopic pregnancy is rare. Ectopic pregnancies occur more frequently in non-contraceptive users than IUD users.
The pill and low folate
Oral contraceptives have been associated with low blood folate levels. Folate or folic acid is essential for fetal brain and spinal cord development. Lack of folic acid can cause birth defects. Folic acid is available as a supplement and is included in most prenatal vitamins. Speak with your obstetric provider about supplementing with folate during oral contraceptive use.
If used properly, the contraceptives discussed are incredibly effective. However, human error or benign failures do occur. If you discover that you are pregnant, discontinue your contraceptive medication or speak with your provider about removing your implant or IUD. The developing fetus will likely sustain no harm from birth control.
- American College of Obstetrics and Gynecology. Effectiveness of birth control methods.
- The American Journal of Nursing. An evidence-based update on contraception.
- British Medical Journal. Maternal use of oral contraceptives and risk of birth defects in Denmark: prospective, nationwide cohort study.
- Cleveland Clinic. Birth control options.
- Journal of Obstetrics and Gynecology Canada. Association between use of oral contraceptives and folate status: A systemic review and meta-analysis.
Show all references
- American College of Obstetrics and Gynecology. Early pregnancy loss.
- American Journal of Gynecology. Contraception and ectopic pregnancy risk: a prospective observational analysis.