Signs that the morning-after pill didn’t work: what to look for (and what to do next)
Wondering if the morning-after pill worked? After taking Plan B One-Step® or Julie Morning After Pill™ the only sure way to know if it didn’t work is if your period is more than seven days late and you have a positive pregnancy test. Common side effects like spotting, nausea, or cramps do not mean it failed —they’re just normal after taking emergency contraception. Changes to your period’s timing are also expected. Take a pregnancy test if your period is over a week late or doesn’t arrive within three weeks. If you’re unsure or worried, talk to your healthcare provider for guidance and support.
If you recently took the morning-after pill from brands like Julie or Plan B, you're probably wondering whether it worked. Waiting for your next period can be stressful, and it's completely understandable to feel anxious during this time.
Did the morning-after pill work? Here’s the truth: The only way to know for sure whether the morning-after pill didn't work is if you miss your period and have a positive pregnancy test.
You may also notice symptoms that make you worry the medication wasn't effective. Try not to read too much into them. Side effects such as spotting, nausea, or cramping are common after taking the morning-after pill and do not necessarily mean it didn't work [1]. The best thing you can do is wait for your next period. If your period doesn't arrive, take a pregnancy test to find out for sure.
The Only Reliable Sign the Julie Morning After Pill™ or Plan B Didn’t Work
If your expected period is more than seven days late, you should take a pregnancy test. This is the only way to know for sure if the morning-after pill didn't work [1].
The days after taking emergency contraception, such as Julie Morning After Pill™ or Plan B, can be stressful and confusing because many of the side effects are similar to early pregnancy symptoms. Common side effects include nausea, vomiting, breast tenderness, fatigue, cramping, and changes to your menstrual cycle [2]. In fact, changes to your period are the most commonly reported side effect [2]. Most other side effects improve within 48 to 72 hours, and your menstrual cycle typically returns to normal within one or two cycles [2].
If your period comes a little earlier or later than expected, that doesn't mean the morning-after pill didn't work. Changes in the timing of your period are a common side effect [2]. However, if you don't get your period within three weeks of taking the morning-after pill, you should take a pregnancy test.
Plan B Side Effects vs. Early Pregnancy Symptoms
Plan B Side Effects | Early Pregnancy Symptoms |
Nausea Fatigue Headache Dizziness Breast tenderness Spotting Cycle changes | Nausea Fatigue Breast tenderness Frequent urination Implantation spotting Missed period |
Signs of pregnancy after the Julie Morning After Pill™ or Plan B include nausea, fatigue, breast tenderness and spotting. The common side effects of the morning-after pill are quite similar to some of these early pregnancy symptoms [2]. While some people may experience several of these side effects, others may not experience any at all. None of these symptoms can tell you either way if the morning-after pill worked or failed. The only way to reliably tell is to take a pregnancy test if you miss your period.
Why the Julie Morning After Pill™ Plan B Can Fail (And How Common Is It?)
The morning-after pill is highly effective when taken correctly and as soon as possible after unprotected sex. However, it’s not a guarantee. But why?
- You took it too late. How soon you take the morning-after pill after unprotected sex can make a difference. It’s best to take the morning-after pill within 72 hours of unprotected sex. How effective is the morning-after pill? It’s up to 95% effective if taken in the first 24 hours. However, it becomes less effective the longer you wait to take it, with an overall effectiveness of about 87–95% when taken within the 72-hour window [4][5].
- You already ovulated. Where you are in your menstrual cycle can affect failure rates. If ovulation has already happened, the morning-after pill won’t work. This is because it prevents pregnancy by delaying or preventing ovulation [5]. If the egg has already been fertilized, it cannot stop a pregnancy that has already started [2].
- Higher body weight. Some studies suggest that the morning-after pill may not be as effective if your BMI is over 25, or if you weigh roughly above 165lbs [3][6]. This doesn’t mean you can’t take the morning-after pill, but there may be more effective emergency contraception options out there [3]. You should reach out to your healthcare provider to discuss which option is best and most effective for you.
- You are taking other medications. Certain medications and herbal supplements, such as rifampin, St. John's wort, and some anti-seizure medications, can interact with the morning-after pill and reduce its effectiveness [2].
- Vomiting right after taking the pill. If you vomit within two hours of taking the morning-after pill, your body may not have fully absorbed the medication. In this case, you may need to take another dose for it to be effective [2].
When to Take a Pregnancy Test After the Julie Morning After Pill™ or Plan B
If you’re wondering how to tell if the Julie Morning After Pill™ or Plan B worked, the answer is to take a pregnancy test. However, it's important to wait long enough before taking a pregnancy test, as testing too soon can result in a false negative.
If you don't get your period within three weeks of taking the morning-after pill, or if your period is more than seven days late, take a pregnancy test as soon as possible [1]. If your home pregnancy test is negative but your period still doesn't come, see your doctor for a blood test. The blood test is more sensitive because it checks your beta HCG level, which is the hormone your body produces during pregnancy. A late period or changes in your menstrual cycle can also be a side effect of the morning-after pill, but it's always best to be sure [2].
What to Do If the Julie Morning After Pill™ or Plan B Didn’t Work
First of all, don’t panic. If you have a positive pregnancy test after taking the Julie Morning After Pill™ or Plan B, the morning-after pill did not work. You should see your healthcare provider as soon as possible. At that point, you have several options. You can choose to continue the pregnancy, consider an adoption plan, or decide to terminate the pregnancy. Whatever you decide, your healthcare provider can offer support and resources to help guide you. If you choose to continue the pregnancy, studies have shown that levonorgestrel (the active ingredient in the morning-after pill) does not increase the risk to the pregnancy or affect fetal development [1].
While we love to share useful and helpful information, the above shouldn’t replace the advice of your healthcare professional. For questions about birth control and other women’s health issues, please talk to your doctor.
How soon can I tell if the Julie Morning After Pill™ or Plan B worked? | You usually won't know whether the Julie Morning After Pill™ or Plan B worked until your next period. There's no way to really "tell" right away. Most people get their period within a week of when it's expected, although it may come a little earlier or later than usual. If your period is more than seven days late or you don't get it within three weeks of taking the morning-after pill, take a pregnancy test. If your test is negative but your period still doesn't arrive, follow up with your healthcare provider for further evaluation. |
Can I take another Julie Morning After Pill™ or Plan B if I'm worried the first one didn't work? | Depending on the situation, you can take another dose of the morning-after pill. For example, if you vomit within two hours of taking it, you should take another dose because your body may not have fully absorbed the medication. However, if you're simply concerned that the first dose didn't work, taking an additional dose will not make it more effective. |
Does spotting after the Julie Morning After Pill™ or Plan B mean it worked? | No — sorry. Light bleeding or spotting is a common side effect of the morning-after pill. Some people experience spotting a few days after taking it, while others have no bleeding at all. Both responses are normal and don't indicate whether the medication worked. Symptoms like spotting, nausea, and cramping are simply side effects. The only way to know if it worked is to wait for your next period. |
Can the Julie Morning After Pill™ or Plan B fail even if I took it within 24 hours? | Unfortunately, yes. Although the morning-after pill is most effective when taken as soon as possible after unprotected sex, it can still fail even if you take it immediately. No emergency contraceptive is 100% effective. If your period is more than seven days late or you don't get it within three weeks of taking the morning-after pill, take a pregnancy test. |
What if my period is only a few days late after the Julie Morning After Pill™ or Plan B? | A period that's a few days late is a common side effect of the morning-after pill and usually not a cause for concern. The medication can temporarily affect your menstrual cycle, so your period may come a few days earlier or later than expected. However, if your period is more than seven days late, take a pregnancy test. If the test is negative and your period still doesn't come, follow up with your healthcare provider. |
Julie wants to keep young women in the driver’s seat of their own stories and provide them with the tools necessary for a happy, healthy sex life.
We know (and have lived!) through the ups and downs of young adulthood firsthand, and we aim to normalize the events, conversations, and questions that come during this period to help destigmatize sexual health. We believe women should live life with total freedom — starting with their ability to choose how, when, and if they become pregnant.
We know that women can make the best choices for themselves when equipped with the right information. We don’t take sexual education lightly and are committed to sharing accurate and factual information through rigorous planning and QA processes. In fact, all Julie content is reviewed by at least two board-certified doctors on our medical board. Learn more about them here.
For more details on our editorial process, see here.
Cordelia Nwankwo, MD, FACOG is a native of Dallas, Texas. She graduated from Texas A&M University with a Bachelor of Science in Biomedical Engineering. She then earned her medical degree from The University of Texas Southwestern Medical School. Dr. Nwankwo completed her training in Obstetrics and Gynecology at UT Southwestern Medical Center and Parkland Hospital. She currently is in private practice in Washington, DC. Dr. Nwankwo’s goal as a provider is to make sure every patient feels heard and able to achieve optimal health.
Education: UT Southwestern Medical School – Doctor of Medicine (MD); Texas A&M – Bachelor of Science (BS)
Maggie Sager, MD, FACOG is a board-certified OBGYN based in Virginia. She earned her medical degree from the University of Louisville and completed her residency in Obstetrics and Gynecology at Lenox Hill Hospital in New York City. Her clinical passions include contraception counseling, caring for adolescent patients, and providing affirming, informed care to patients in the LGBTQ+ community. She is a committed advocate for her patients, dedicated to making sure they have the knowledge and support they need to make confident, informed decisions about their bodies and their health.
Education: Lenox Hill Hospital, Obstetrics and Gynecology Residency; University of Louisville, Doctor of Medicine (MD); University of Vermont, Bachelor of Arts (BA)
Tessa Commers, MD, FAAP, MS is a board-certified pediatrician based in the Seattle area with a particular interest in adolescent health and sexual education. In addition to clinical practice and serving as Head of Medical at Julie, Tessa also founded AskDoctorT — an education platform with over a million followers across Instagram, TikTok, and YouTube — aimed at improving adolescent health literacy and body confidence. She also hosted and wrote the puberty podcast “That’s Totally Normal!” and has contributed to peer-reviewed publications and educational initiatives focused on child and adolescent wellbeing.
Education: Children’s Mercy Hospital, Kansas City – Pediatric Residency; University of Nebraska Medical Center – Doctor of Medicine (MD); University of Nebraska Medical Center – Master of Science (MS, Genetics, Cell Biology and Anatomy); New York University – Bachelor of Arts (BA)
