This is the single most common fear about the morning-after pill, and it keeps people up at night long after the moment has passed. So here is the clear, evidence-based answer first: no, Plan B does not make you infertile. It does not cause sterility, it does not damage your ovaries or your eggs, and it does not reduce your ability to get pregnant later. In fact, your fertility returns right away, which is the opposite of the worry. This guide explains exactly why, what the research shows, and why the temporary cycle changes people notice get mistaken for something permanent.
The short answer: no, Plan B does not cause infertility
Taking the morning-after pill to prevent a pregnancy does not make it harder to get pregnant in the future. That is the conclusion of the bodies that study this most carefully. MotherToBaby, a service of the Organization of Teratology Information Specialists, states it plainly: levonorgestrel taken for emergency contraception does not make it harder to get pregnant later. Major clinical references, including the Cleveland Clinic, say the same, that the pill does not harm your chances of getting pregnant in the future or affect your fertility.
This holds whether you have taken it once or more than once, and whether you took Plan B itself or one of its generics like My Way, Take Action, or Julie, which contain the identical active ingredient. The pill is not a sterilizing drug, it is a contraceptive that works on a single moment in a single cycle, and then it leaves your system.
If you are anxious in the moment, the most useful thing is usually clarity about your own timing rather than worst-case worry. The free emergency contraception calculator maps your fertile window in about a minute, and then this guide is here for the reassurance.
One distinction will make this whole article click, so it is worth stating up front. There is a world of difference between a medicine temporarily nudging your current cycle, which Plan B can do, and a medicine permanently harming your ability to conceive, which Plan B does not do. Almost all of the infertility fear comes from confusing the first thing for the second. A late period, some spotting, or an off month is the first kind of thing, and it is precisely what people misread as the second. Keep that one distinction in mind and the rest of this guide follows from it almost automatically.
Why Plan B can’t affect your fertility
To trust the reassurance rather than just hear it, it helps to understand how the pill actually works, because the mechanism makes lasting harm essentially impossible.
It acts on a single ovulation, then it’s done
Plan B contains levonorgestrel, and its main job is to blunt the surge of luteinizing hormone that triggers an ovary to release an egg. Researchers who studied this directly found that the pill suppresses that hormonal surge, delaying or preventing ovulation for that one cycle. It is a one-time intervention aimed at one event. It does not reach forward into future cycles, and it does not change how your ovaries will behave next month, the month after that, or in the years to come when you may actually want to conceive.
It clears your body within days
Levonorgestrel does not linger. Its half-life is roughly a day, and only trace amounts remain after about four days, so within a short window the active hormone is essentially gone. A medicine that has already washed out of your system cannot be quietly damaging your fertility weeks or months later. There is simply nothing left to act.
It doesn’t touch the things fertility depends on
This is the part that settles it. Long-term fertility depends on your supply of eggs, the health of your ovaries and fallopian tubes, and your hormonal cycling. Plan B does not deplete your eggs, damage your ovaries, scar your tubes, or alter your long-term hormones. The table below lays out what it does and does not touch.
You are born with your lifetime supply of eggs. Plan B does not use them up, destroy them, or speed up their loss. Delaying one ovulation does not cost you an egg.
The pill briefly influences the hormonal signal to one ovary for one cycle. It does not damage the ovaries or change how they work going forward.
Plan B does not scar or block your tubes. Large studies also find it does not meaningfully raise the risk of ectopic pregnancy, which is the tube-related concern people sometimes have.
Your next period may come earlier or later and be lighter or heavier, and you may spot. This is the pill shifting one cycle, and it resets on its own.
The dose is a one-time pulse that clears in days. It does not rewire your hormonal cycling or cause a lasting imbalance.
There is also a useful comparison hiding in plain sight. Levonorgestrel is the same hormone used in everyday birth control pills and hormonal IUDs, which people take for years. Even after prolonged use of those, fertility returns once they are stopped. If years of levonorgestrel do not impair future fertility, a single emergency dose has no plausible route to doing so. For the hormonal side of things specifically, our guide on whether Plan B messes with your hormones goes deeper.
It is also worth dispelling a quiet, specific version of the egg fear, the idea that delaying an ovulation somehow wastes an egg or runs your reserve down faster. It does not work that way. Your body naturally loses eggs every cycle whether or not you ovulate, and whether or not you ever take a contraceptive, so postponing a single release does not subtract from your future supply. Hormonal birth control, which suppresses ovulation month after month for years, does not lower the age at which fertility declines, and an occasional emergency pill is far less than that. The arithmetic that worries people, fewer ovulations now meaning fewer eggs later, simply is not how ovarian biology behaves.
Temporary cycle changes vs permanent infertility
Here is the confusion at the heart of almost every infertility worry. Plan B can absolutely change your current cycle, and those changes can feel alarming if you do not expect them. But a disrupted cycle is not a sign of damaged fertility. They are completely different things.
After the pill, your next period might arrive earlier or later than usual, it might be heavier or lighter, and you might notice some spotting in between. Reviews of the research find that while the pill can shift the timing of that next bleed, it does not disrupt the return of a normal menstrual cycle afterward. In other words, the blip is for one cycle, and then your body picks up its usual rhythm.
The trouble is that an off-schedule period is exactly the kind of thing an anxious mind reads as a red flag. Someone takes Plan B, their period is a week late, and the catastrophic thought arrives: something is broken. But a late period after emergency contraception is usually just the pill having delayed ovulation, which pushes the whole cycle back. It is the expected behavior of a working contraceptive, not evidence of harm.
What a temporary change looks like
An early, late, lighter, or heavier period for one cycle; some spotting; then a return to your normal pattern within a cycle or two. Annoying, but harmless.
What infertility would look like
A persistent, long-term inability to conceive despite trying, with no return to normal cycling. Plan B does not cause this, and the evidence does not link it to this.
If your cycle feels off after the pill, that is well-trodden territory rather than a crisis. We cover the timing questions in detail in can Plan B mess up your cycle and the spotting and bleeding questions in how long Plan B spotting lasts. The one firm rule: if your period is more than about a week late, take a pregnancy test, because the most common reason for a missing period after sex is pregnancy itself, not anything the pill did to your fertility.
You can get pregnant right after taking it
This single fact, once it lands, tends to dissolve the infertility fear entirely. Your fertility does not pause and then slowly recover after Plan B. It is intact the whole time, and you can become pregnant very soon afterward, including in the same cycle.
Clinical guidance is explicit that after taking levonorgestrel emergency contraception, you can attempt to get pregnant again as soon as your next cycle if you want to. There is no waiting period for your fertility to come back, because it never left. And here is the part that surprises people: because the pill works by delaying ovulation, you can actually become pregnant later in the same cycle if you have unprotected sex again after taking it. The delayed egg still arrives, just later, and there is nothing to stop it being fertilized.
Read that twice, because it matters both ways. The fact that you remain fully fertile after Plan B is reassuring if you are worried about infertility. But it also means the pill is not ongoing protection. If you have unprotected sex again in the days after taking it, you are at risk of pregnancy from that new encounter. Emergency contraception covers the event that already happened, not the next one.
So the honest framing flips the worry on its head. People come to this question afraid that Plan B might have switched their fertility off. The reality is the opposite problem: your fertility is fully on, which is exactly why you should not rely on repeated emergency pills as a method of birth control. If you find yourself reaching for it often, our guide on taking Plan B many times and a conversation with a clinician about ongoing contraception are the better path.
What the research actually shows
Reassurance is more convincing when you can see what it rests on, so here is the evidence in plain terms. Several independent lines of research all point in the same direction, and they reinforce each other.
Direct guidance on getting pregnant later
MotherToBaby, the public information service of the Organization of Teratology Information Specialists, reviews the published studies and states directly that taking levonorgestrel for emergency contraception does not make it harder to get pregnant in the future. That is about as clear as medical guidance gets, and it comes from a body whose entire purpose is assessing the reproductive safety of exposures.
What a major review found
A 2022 review in the journal Contraception looked specifically at the effects of levonorgestrel emergency contraception on implantation and fertility. It reached several reassuring conclusions at once. It found no increased risk of miscarriage, fetal abnormality, or child development problems in pregnancies that occurred after exposure to the pill. It found no indication that the pill disrupts the return of a normal menstrual cycle in the cycle that follows. And it noted that there is substantial evidence that levonorgestrel-only contraceptives do not impair future fertility even after prolonged use, which led the authors to conclude that repeated use of emergency contraception is unlikely to affect future fertility either.
Why the drug clears the case, literally
The same review points to the pharmacology. Levonorgestrel has a short half-life, on the order of a day or two, with only trace amounts remaining after about four days, and its clearance is not influenced by how long or how often it has been used. A drug that leaves the body quickly and does not accumulate has no mechanism for slowly eroding fertility over time. On top of that, three separate systematic reviews on fertility after contraceptive use have all concluded that levonorgestrel-containing methods do not impair future fertility.
It is worth being honest about one limitation: long-term fertility studies focused only on emergency contraception are limited, simply because it would be hard and unnecessary to run them. But the conclusion does not depend on a single study. It rests on the mechanism, the rapid clearance, and the very large body of evidence on the same hormone used in everyday contraception. Those lines converge, which is what makes the answer robust rather than tentative. If you would like to see how that timing plays out in your own cycle, the emergency contraception calculator maps it for you.
Where the infertility myth comes from
If the evidence is this clear, why is the fear so widespread? It is worth understanding, because seeing the roots of a myth helps you stop believing it. The infertility worry comes from a few understandable places.
Confusing contraception with sterilization
Some people half-remember that certain procedures, like tubal ligation, permanently end fertility, and they fear a strong pill might do something similar. But a contraceptive pill and a surgical sterilization are nothing alike. Plan B prevents one potential pregnancy and then clears out; it does nothing irreversible.
The fear of “messing up your hormones”
Because Plan B is a hormone, and because it can shift one cycle, people worry it has thrown their system permanently out of balance. The dose is a brief pulse that clears in days, and your hormonal cycling resumes on its own. A temporary nudge is not a permanent imbalance.
Anecdotes about irregular cycles
Someone has an off period after the pill, posts about it, and the story spreads as proof of harm. But irregular timing for a cycle or two is the expected, temporary effect, not evidence that anyone’s fertility was damaged. The plural of anecdote is not data.
Confusion with the abortion pill
Plan B gets mixed up with the abortion pill, a different medicine, and fears about one get attached to the other. They are not the same drug and do not do the same thing, as our guide on whether Plan B is an abortion explains. Neither, for the record, causes infertility.
There is one more amplifier worth naming: the internet itself. Fertility fears spread fast online because frightening claims travel further than calm corrections, and a single dramatic post can reach far more people than a quiet medical fact sheet ever will. When you search a worry, the most alarming results are often the loudest rather than the most accurate, which can leave a false impression that the danger is real and widely accepted when the medical consensus is the opposite. Reading a sourced explanation like this one, rather than a comment thread, is part of how you weigh the evidence fairly.
None of these roots hold up once you look at them directly. The fear is understandable, but it is built on misunderstandings rather than evidence.
What about taking it many times?
This is the natural follow-up worry: maybe one dose is fine, but what if I have used it several times, or use it often? It deserves a careful answer, and the reassuring news is that the evidence still does not point to infertility.
Reviews of the research conclude that repeated use of levonorgestrel emergency contraception is unlikely to affect future fertility. Part of the reasoning is that the drug clears from the body the same way regardless of how often it is used, so it does not build up or accumulate damage. The other part is the comparison we keep returning to: levonorgestrel-only contraceptives taken continuously for years do not impair fertility, so intermittent emergency use has no plausible mechanism to do so either.
That said, frequent reliance on emergency contraception is worth addressing for a different reason. It is less effective and more disruptive than regular contraception, it tends to mean recurring anxiety, and it can scramble your cycle more often. So if you are using it repeatedly, the issue is not your fertility, it is that there is probably a more comfortable and more reliable option for you. We go through the repeated-use question in full, including what the studies say, in can taking Plan B too many times make you infertile, and the question of dosing and taking too much in what happens if you take too much Plan B.
The practical takeaway: repeated emergency contraception will not make you infertile, but it is a sign it may be worth talking to a clinician about a regular method that fits your life better, with less stress each time.
Does ella or the copper IUD affect fertility?
Plan B is the most common emergency contraceptive, but it is not the only one, and the fertility question deserves an answer for all three options, because none of them threatens your ability to conceive later.
ella (ulipristal acetate)
ella works much like Plan B, primarily by delaying ovulation, and like Plan B it clears from the body and acts on a single cycle. It is not linked to infertility, and your fertility returns just as it does after levonorgestrel. The differences between the two pills are about how long each stays effective and how each is affected by body weight, not about any risk to your future fertility, and we lay those differences out in ella versus Plan B.
The copper IUD
The copper IUD is the most effective emergency contraceptive, and it is also fully reversible. It works by preventing fertilization while it is in place, and once a clinician removes it, your fertility returns promptly. People regularly conceive soon after a copper IUD is taken out. There is no lasting effect on your ability to get pregnant, which is one reason it doubles so neatly as long-term, on-and-off birth control.
The hormonal IUD, for completeness
Although it is not a first-line emergency method, the hormonal IUD that some people ask about uses the same family of hormone as Plan B and is likewise reversible, with fertility returning after removal. Across the board, the reversible methods are reversible in the way that matters most: your fertility comes back.
So whichever option is on the table for you, fertility is not the deciding factor, because none of them put it at risk. The real decision is about effectiveness for your timing and body weight, which is exactly what the Waldev calculator is built to help you weigh, rather than leaving you to guess under stress.
Does Plan B affect future pregnancies or a future baby?
Beyond the ability to conceive, people also ask whether the pill could harm a pregnancy that happens later, or a future baby. Again, the evidence is reassuring on both counts.
A pregnancy you conceive in a later cycle, after the pill has long cleared your system, is simply a normal pregnancy. The medicine is not present and has no role in it. And for the rarer situation of a pregnancy that occurs in the very cycle the pill was taken, when it did not prevent ovulation, reviews have found no increased risk of miscarriage, fetal abnormality, or child development problems in pregnancies conceived after levonorgestrel emergency contraception. ACOG likewise notes that studies of hormonal exposure around conception, including older higher-dose formulations, have found no increase in risk to the pregnant person or the developing fetus.
So the answer to “does Plan B affect future pregnancies” is no, in the ways that matter. It does not reduce your chance of getting pregnant later, it does not harm a future pregnancy, and it is not linked to birth defects. If you took it without realizing you were already pregnant, that specific situation is covered in our guide on whether Plan B can cause a miscarriage, and the short version there is also reassuring.
If you’re worried about fertility, here’s where the worry belongs
Sometimes the anxiety about Plan B is really a broader worry about being able to have children one day, and the morning-after pill becomes the thing it attaches to. If that resonates, it can help to know what genuinely influences fertility, because emergency contraception simply is not on that list.
The factors that actually shape someone’s ability to conceive include things like age, certain medical conditions affecting ovulation or the reproductive organs, and some untreated infections. None of those have anything to do with taking a contraceptive pill. Plan B does not create any of them, and using it does not move you toward any of them.
One genuinely relevant point sits next door to this topic. Emergency contraception does not protect against sexually transmitted infections, and some untreated STIs can, over time, affect fertility. So if a situation called for the morning-after pill, it can also be a sensible moment to consider STI testing. That is not about Plan B harming you, it is about catching something separate that actually could matter, and it is an easy, private thing to ask a clinician or clinic about.
If you have ongoing concerns about whether you will be able to get pregnant in the future, whether because of irregular cycles, a known condition, or simply persistent worry, the right move is a conversation with a clinician who can look at your actual situation. They can reassure you, run any checks that make sense, and address the real factors, which a single emergency pill is not one of. Putting the worry where it belongs is itself a relief, and it means you can stop assigning blame to a medicine that did exactly what it was supposed to do. In the meantime, if your immediate question is whether you were even at risk this cycle, the free calculator can give you a clear, calming answer.
Real-world scenarios
Here is how the fear shows up in practice, with the calm read on each. These are illustrative examples for understanding, not medical advice for your specific situation.
No. A late period after the pill is usually just delayed ovulation pushing the cycle back, which is the pill working as intended. It is a temporary timing shift, not infertility. If it goes past about a week late, take a pregnancy test, since the leading cause of a missing period after sex is pregnancy, not harm to your fertility.
No. Repeated use is not linked to infertility, and the drug clears the same way each time without accumulating. The real takeaway is comfort, not fertility: using it that often is a good reason to ask a clinician about a regular method that would be easier and more reliable for you.
Yes. Your fertility is intact, and you can try to conceive as soon as your next cycle. The pill will have cleared your system entirely, and a pregnancy conceived after it is a normal pregnancy. There is no waiting period and no lingering effect to plan around.
Notice the through-line: in every case the answer is that your fertility is fine, and the only variable worth attending to is whether you are currently pregnant, which a test settles. If your underlying concern is timing and risk in the first place, you can always run your dates through the calculator to see your fertile window clearly.
Quick reference: Plan B and your fertility
Does not cause infertility or sterility.
Does not damage your ovaries, eggs, or fallopian tubes.
Does not reduce your ability to get pregnant later, even with repeated use.
Does not harm a future pregnancy or cause birth defects.
Can temporarily shift one cycle’s timing, which resets on its own.
Leaves your fertility fully intact, so you can conceive as soon as the next cycle.
Your fertility is not the thing to worry about. The useful question is whether your timing put you at risk and which option fits. The Waldev emergency contraception calculator estimates your fertile window and shows which methods are still effective, free and private, in about a minute.
Frequently asked questions
Can Plan B make you infertile?
No. Taking levonorgestrel emergency contraception does not make it harder to get pregnant in the future. It works on a single ovulation, clears from the body within days, and does not damage your ovaries, eggs, or tubes. Major medical references confirm it does not affect fertility.
Can Plan B make you sterile?
No. Plan B is a contraceptive that prevents one potential pregnancy, not a sterilizing drug. It does nothing irreversible to your reproductive system. Sterility is not a known effect, and your fertility returns immediately after the pill clears.
Does Plan B affect your fertility or future pregnancies?
No. It does not reduce your ability to conceive later, and a pregnancy conceived after the pill has cleared is a normal pregnancy. Research finds no increased risk of miscarriage, birth defects, or child development problems in pregnancies after levonorgestrel emergency contraception.
How long after Plan B can you get pregnant?
Right away. Your fertility is not paused by the pill, so you can attempt to conceive as soon as your next cycle. You can even become pregnant later in the same cycle if you have unprotected sex again, because the pill only delays one ovulation rather than stopping your fertility.
Can taking Plan B many times make you infertile?
No. Reviews conclude that repeated use is unlikely to affect future fertility, partly because the drug clears the same way each time and does not accumulate. Frequent use is worth discussing with a clinician, but for comfort and reliability, not because it threatens your fertility. See our dedicated guide on taking Plan B many times.
Will Plan B make it harder to conceive later?
No. There is no evidence that emergency contraception makes future conception harder. It is the same hormone used in regular birth control, which does not impair fertility even after years of use, so a single emergency dose has no route to doing so.
Does Plan B damage your eggs or ovaries?
No. The pill briefly influences the hormonal signal for one cycle, but it does not deplete your egg supply, destroy eggs, or damage your ovaries. You are born with your eggs, and delaying one ovulation does not cost you any.
My period is late or irregular after Plan B. Does that mean I’m infertile?
No. A late or irregular period after the pill is a temporary timing shift, usually from delayed ovulation, and it resets on its own within a cycle or two. It is not a sign of infertility. If your period is more than about a week late, take a pregnancy test to rule out pregnancy.
The bottom line
Plan B does not make you infertile. It does not cause sterility, it does not damage your eggs, ovaries, or tubes, and it does not reduce your ability to get pregnant later, even if you have used it more than once. Your fertility returns immediately, which is the opposite of the fear. The cycle changes people notice are temporary timing shifts, not signs of permanent harm. If your cycle is off, give it a cycle or two, and test if your period is more than a week late.
Since fertility is not the concern, the useful question is whether you were at risk and which option fits. Use the free emergency contraception calculator, and for related worries see whether Plan B can mess up your cycle or affect your hormones, or browse our health guides.
Sources & references
This article is based on guidance from major medical bodies and peer-reviewed research. Always confirm details with a current source or a clinician.
Levonorgestrel (Plan B One-Step) fact sheet: taking it does not make it harder to get pregnant in the future. mothertobaby.org
Review on the effect of levonorgestrel emergency contraception on implantation and fertility, including return of the cycle and repeated use. contraceptionjournal.org
American College of Obstetricians and Gynecologists, Emergency Contraception (no increased teratogenic or ectopic risk). acog.org
Morning-after pill overview: it does not harm future fertility. my.clevelandclinic.org
Important disclaimer
This guide is for general education only and is not medical advice, nor a substitute for care from a qualified clinician. It does not diagnose, treat, or create a doctor–patient relationship. Any figures, timings, and examples are illustrative and will vary from person to person. If you have concerns about your fertility, irregular cycles, a late period, or any other symptom, or if you are trying to conceive, speak with a doctor or other licensed healthcare professional. Medication labeling and availability can change and differ by country. Waldev is an independent education and tools website and is not affiliated with, endorsed by, or sponsored by Plan B One-Step, ella, the FDA, ACOG, MotherToBaby, or any product or organization named on this page. Brand names are used only for identification.