Can You Get Pregnant on Birth Control?

By Terez Malka, MD
Medically reviewed checkmarkMedically reviewed
March 9, 2022

Approximately 65% of those who identify as women in the United States use some form of birth control. Birth control pills and other contraceptives are used to prevent conception (getting pregnant). 

However, this does not mean that you cannot get pregnant while on birth control.

Besides abstaining from sexual intercourse, there is no form of birth control that has a 100% success rate.

That is why it is important to understand the importance of using birth control properly. 

This article will explain why and how birth control pills can fail and also discuss any signs of early pregnancy to watch out for so you can be best prepared. 

Can You Get Pregnant on Birth Control?

The short answer is yes; you can get pregnant on birth control. However, we need to dig deeper to understand why and how this can happen. 

Birth control pills are 99% effective, and they seem to have a better record of working correctly than humans! Approximately nine out of one hundred birth control pill users will get pregnant.

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Why Does Birth Control Fail? 

Hormonal birth control tends to fail when not used correctly.

It is easy to forget doses or medical appointments in today’s fast-paced world.

Stress and other obligations can all contribute to not using your birth control precisely as directed, which can increase your risk of pregnancy.

In very rare cases, birth control can fail even when used perfectly.

Common reasons why hormonal birth control fails include:

  • Forgetting to take birth control: Many people forget to take the birth control pill at the same time every day, or they might skip a pill too often. Alcohol or drug use might be a culprit here. While alcohol and recreational drugs do not directly affect birth control pills, they can affect your ability to remember to take your pill when required.
  • Illness: If you are sick, you may vomit your birth control pill along with everything else that failed to absorb into your body in time.
  • Diarrhea: If you have severe diarrhea that lasts for many hours of days at a stretch, the pill will pass through your body quickly without getting absorbed.
  • Incorrect timing: Some people forget to start the next cycle of pills (or patch or ring) as soon as they’re supposed to. Skipping a few days between each pack of birth control pills will make them less effective. Start your new pack of pills or replace the patch or ring as directed on time to avoid getting pregnant.
  • Medication interactions: Some drugs and medications can interfere with the effectiveness of oral contraceptives. Antibiotics such as Rifampin, antiretrovirals (ARVs) like darunavir (Prezista) and nevirapine (Viramune), and antifungals like ketoconazole (Nizoral) may interfere with hormonal birth control pills. Your doctor will adjust your medicine dosage and guide you when combining any medications. They may recommend you use a backup method of contraception like condoms while taking these medications.

Because most birth control has hormones, it is important to use them as directed to prevent sperm from fertilizing an egg.

If any of the above occurs, your body’s hormone levels will change immediately.

This may cause your body to ovulate, increasing your pregnancy chance. 

Preventing Birth Control Failure 

To prevent birth control failure, one thing you can do is to maintain a strict protocol of its usage and follow instructions thoroughly.

If you find it difficult to keep track of your daily birth control pill intake, then set a reminder on your phone.

It can be a simple daily alarm that rings at the same time each day when it is convenient for you to take your pill. 

If taking a daily pill is difficult for you, other home contraceptive options like the patch, the vaginal ring, or a longer-term option like an implant, Depo shot, or IUD may be a better option for you.


There are also plenty of apps and calendars available online to help you keep track of your contraceptive pills.

These apps will help you with natural family planning, aid in keeping track of your cycle, and monitor your ovulation cycles.

Additional Protection

Even if you use birth control or monitor your fertility cycles, you may still want to consider extra protection like condoms.

Condoms are available for both penises and vaginas.

Condoms are barrier methods of contraception that also help keep STIs and STDs at bay and can provide additional protection from pregnancy.

It is important that you practice safe sex and consensual sex at all times. 

It can take up to several weeks for hormonal birth control to take effect.

Use a backup method of birth control for a start to avoid an unplanned pregnancy for the amount of time directed by your prescriber or pharmacist. 

Have questions about birth control? Chat with a doctor through K Health.

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Symptoms of Pregnancy

If you miss a period in your menstrual cycle, take a home pregnancy test to see if you are pregnant. Take another test 7 days after your missed period, even if your first test is negative. 

You can also book a blood test with your doctor or primary care for pregnancy confirmation- though this is rarely needed unless you’re experiencing signs of a complication.

When you’re on birth control, it is easy to ignore the early signs of pregnancy, such as:

  • Missed or late periods or spotting
  • Irregular vaginal discharge or discoloration
  • Tender breast and soreness in the chest area
  • Nausea, vomiting, or diarrhea
  • Water retention and bloating
  • Fatigue, tiredness, and aches in the body
  • Headaches and migraines
  • Changes in frequency of urination
  • Changes in appetite and aversion to certain tastes and smells

How K Health Can Help

Did you know you can access online urgent care with K Health?

Check your symptoms, explore conditions and treatments, and if needed, text with a healthcare provider in minutes. 

K Health’s AI-powered app is based on 20 years of clinical data.

Frequently Asked Questions

How do you know if you're pregnant on the pill?
If you are on the birth control pill, it can take a few days and sometimes even several weeks for pregnancy symptoms to get noticed. Look for early signs of pregnancy, including a missed period, nausea, tenderness in the breasts, and a persisting headache. You may take a home pregnancy test to check, but sometimes you may need to do another test after a few days to a week to get a more accurate result, depending on your cycles. Your primary care provider or doctor can help you figure out the right time to test and the best kind of test to take.
What makes birth control fail?
Hormonal birth control is a very effective way to prevent pregnancy. However, they are not 100% effective. Most often, birth control fails due to improper or careless use. If you forget to take the pill, take it at inaccurate times or skip the pill multiple times in a month, they will be more likely to fail. Aside from abstinence, no birth control is 100% effective even when used properly.
How likely is it to get pregnant when not on birth control?
There is a high chance that sexually active people who have not yet undergone menopause will get pregnant when not on birth control. Most will get pregnant within one year of trying, particularly during the period an egg is released from the ovary.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Terez Malka, MD

Dr. Terez Malka is a board-certified pediatrician and emergency medicine physician.