Clearblue Easy Fertility Monitor Review

If you have had trouble conceiving a baby or just want to understand your fertility cycle better, you may have heard of the Clearblue Easy Fertility Monitor.

My wife and I bought one last fall with the intent of using it initially to help us get pregnant and then later as an additional tool in our practice of Natural Family Planning.

Fortunately for us, but unfortunately for a long-term review, we were blessed to conceive our third child the first month that we used the fertility monitor.  However, we learned all about it, gained some experience using it, and I even made my first YouTube video to show the world what comes in the box when you buy a Clearblue Fertility Monitor!

Add More Sizzle to Your Sex Life

Download This Simple 10-Minute Tip to Break Free of the Bedroom Routine.

How Does the Fertility Monitor Work?

In the most basic sense, the monitor uses urine samples to identify days of High Fertility and Peak Fertility.  Obviously, if you have sex on those days, especially the one or two Peak Fertility days, your chances of achieving pregnancy are greatly improved.

There are only a limited number of days during the menstrual cycle when sex can lead to pregnancy.  Conception is most likely to occur if you have intercourse on the day the ovaries release a new egg, which is called ovulation, or during the days leading up to it.  The fertility monitor tracks a woman’s level of estrogen and LH to predict when ovulation is approaching and indicate the day it has occurred (the Peak Fertility day).

The Clearblue Easy Fertility Monitor prompts you on the days you need to take a urine sample.  This will be a total of ten tests per cycle for more “typical” cycle lengths, or it will be twenty tests for long or irregular cycles. When you start using the monitor, you’ll set a testing time window that needs to be maintained, though you can test up to three hours before or after the time you specify.  When you turn it on, the fertility monitor will tell you whether you need to test that day or not.

In general, the manufacturer recommends that the monitor be used by women with menstrual cycles lasting 21-42 days.  As you test for several cycles, the monitor begins to “learn” about your menstrual patterns, and the testing days will be better defined.

What’s in the Box?

The answer to this question is not much!  Here’s a short video I made to show what the monitor looks like and what you get when you buy one.

Our Experiences With the Monitor

When we started thinking about buying a monitor, I did a lot of research and was convinced that the Clearblue Easy Fertility Monitor was the single best ovulation tracker on the market.  We also spent a lot of time learning how it worked, which was aided by the understanding we’ve gained of fertility cycles through our practice of Natural Family Planning.

Like I said, we only used the monitor for one month before Bethany became pregnant (she’s due in July!).  As luck would have it, she had a crazy-long cycle that month of over 50 days, and we hit the max of 20 tests before she ever ovulated.  Of course, we knew what was going on since we were also using the sympto-thermal methods of NFP (which helps prove the point that NFP is not only for those with nice, regular cycles).

With this super-long cycle, the monitor basically stopped testing and would have waited until we told it her period had started.  It would have then started over testing the next cycle with the “knowledge” of her long menstrual cycle taken into consideration.

Of course, that next cycle is several months away at this point since we successfully conceived a baby.  However, even based on our limited first-hand experience, I can tell you that the fertility monitor was very easy to use, and I am confident that it is effective in identifying the days of high fertility and communicating this simply to couples hoping to achieve pregnancy.

And that’s what it’s all about when choosing a fertility monitor.

We plan to use ours again after the baby arrives and Bethany’s hormones calm down.  We are hopeful that it will become an additional tool in our practice of Natural Family Planning moving forward, and we plan to learn more about this approach by studying up on the Marquette Model of NFP, which includes the Clearblue Easy Fertility Monitor in its methods.

UPDATE: It’s now mid-2012, and we’ve been using our monitor for nearly two years since the birth of our daughter Avery.  We LOVE it!  The Marquette Model has been a real Godsend, and this monitor has made it so much easier to track Bethany’s fertility each month.

Where Can You Buy One (and Learn More)?

We did a lot of research on fertility monitors, and I can tell you that you will find the best price and most dependable service by simply buying your monitor through good ole Amazon.  This is not a cheap investment in fertility awareness, and I would encourage you to stick with a trusted resource.  Amazon also periodically runs sales on the Clearblue Easy Fertility Monitor.

Please note: When you buy a monitor, it does not come with the testing sticks that you’ll need.  And you’ll have to continue buying testing sticks as long as you are using the monitor.

Fortunately, Amazon offers a combination package where you get both the monitor and test sticks to get you started at a slightly reduced price.

When you visit the Amazon page for the Clearblue Easy Fertility Monitor, you’ll also find customer reviews and additional information on the product.  I always find this additional peer feedback to be helpful when considering such an important purchase.

Clearblue Easy Fertility Monitor ReviewClearblue Easy Testing SticksClearblue Easy Fertility Combo

If you do decide to buy a fertility monitor or testing sticks, I’d really appreciate it if you used the links above.  For referring you to their site, I get a (very) small commission from Amazon and your price is unaffected.  Thanks in advance for your continued support of Engaged Marriage!

Frequently Asked Questions

When should I start using Clearblue Fertility Monitor?

You want to start using Clearblue fertility monitors 17 days before you start your next cycle. If your cycle is around 21 days long you should start at day 5, if you have a 30-day cycle you should aim for day 13, while if you have a cycle that is 40 days or more you should start at day 17.

What does Clearblue high fertility mean?

Clearblue displays high fertility as a flashing smiley face, “high fertility” days significantly increase your odds of getting pregnant. Your period of high fertility lasts roughly 6 days and starts 5 days before you begin ovulating. Ending on the day of ovulation itself.

How accurate is Clearblue Fertility Monitor?

Clearblue’s fertility monitors are highly accurate for those with cycles between 23 and 37 days in length. Those with cycles that are routinely shorter than 23 days or longer than 37 days, where your LH levels and surge are harder to detect will find Clearblue’s monitors less accurate.


About the author 


Dustin Riechmann created Engaged Marriage to help other married couples live a life they love (especially) when they feel too busy to make it happen. He has many passions, including sharing ways to enjoy an awesome marriage in 15 minutes a day, but his heart belongs with his wife Bethany and their three young kids.

Leave a Reply

Your email address will not be published. Required fields are marked

  1. We’ve been using the Marquette Model and the monitor for 6 years and I don’t think we would do it any other way! I agree, the monitor is SO easy to use. A bit of an investment, but worth it in my opinion.

    Dustin – something to keep in mind for after the baby comes… The Marquette Model does have instruction on how to use the monitor while breastfeeding, even before cycles return. If you haven’t seen it already you can find it on their site.

    1. Angela, I’m going to look up the Marquette Model for NFP while nursing. I am due in September, and I would feel much more confident with NFP during the first year if I had an actual method of measuring the hormones in my body. My temps always look like an earthquake and other signs are very strange, too, so I would rather spend the same amount I would pay for a minipill copay each month on testing sticks and know for certain when the luteinizing hormone is on the rise.

    2. Thanks so much, Angela! This is something we will definitely be learning more about over the next few months. For someone like us who is already trained in NFP (through the Couple-to-Couple League’s sympto-thermal method), do you think we can learn all we need about the Marquette Model by reading on their site?

      1. Dustin – You certainly couldn’t learn the entire method in an effective manner from the site, but going from sympto-thermal to sypmto-thermal+monitor is a pretty easy step. At that point it’s really just another cross check. As for the breastfeeding part, I do believe that all that information is on the site. What they outline is how to use the monitor before cycles return. Many NFPers will already be doing what they can to watch mucus and temps while breastfeeding, so again… another cross check. IMO, though, the monitor would be more effective at detecting ovulation before cycles return since breastfeeding can really mess with mucus. I’ve never personally used the monitor in this manner (my cycles return crazy quick even with breastfeeding – if that’s not TMI), so I can’t speak from experience though.

        1. Thanks, Angela. We will definitely be looking into this more, for self-education if nothing else. And practically nothing is TMI around here. 😉

          1. Dustin, all of the Marquette educational info. is on their website except for ind-depth info. about temp. taking, which a Marquette trained instructor can provide you with.

            The key to looking for the return of fertility in the postpartum period is looking for the return of mucus, which can be precipitated by longer periods between breastfeeding/introduction of solids etc.

        2. Dear Angela and Dustin,

          I have a 7 month old whom I am breastfeeding until he self weens. My husband and I would like to get pregnant again sooner than later due to my age (late 30s). We used the Clearblue Fertility Monitor to help conceive our first child and we would like to use it again to help with the 2nd. But I have not started my cycles again due to breastfeeding. I searched the Marquette website for the outline you mentioned above about how to use the monitor when not in cycle and I could not find anything.

          I would greatly appreciate any help or insight you can give me into how to use the CBFM under the circumstance of not having a period yet. Thanks!

          1. Lilly,

            Here’s the direct link. On the left side should be a menu with “breastfeeding protocol for fertility monitor” and “breastfeeding protocol for mucus” as the first two links.

            Ultimately, you’re at the mercy of your cycles and when they choose to return. Are you night nursing? If you want to try (no guarantees) to speed the return of your cycles you could try working towards eliminating feeds between midnight and 5am. Nursing in that time frame can be especially helpful in keeping your cycles at bay.

        3. An important update for Dustin and everyone reading this.

          The Marquette website now has a note at the bottom of the page to say that the website is no longer being updated, and that up-t0-date information can be found in their online forums (which do require payment to join.) This is because they do not have the funds to continue going as they were.

          At the current time, for women in regular cycles (not the first 6 post-partum/breastfeeding cycles) the website information is correct.
          However, anybody wanting to use the Marquette Method who is post-partum and had not returned to cycles, or is post-partum and has returned to cycles, but is within the first 6 full cycles and is still breastfeeding, should get an instructor or join the forum. The information on the website for those circumstances is NOT current, and there will be a reduced chance of an unintended pregnancy if the current instructions are followed.

  2. We used this fertility monitor in conceiving our first two children. (The third was unplanned, so that’s why we didn’t for her. LOL) I say “we” loosely, as my husband wasn’t the one involved with the monitor beyond knowing when I was at my peak fertility!

    Like you, I found it to be very easy to use – and, more importantly, to understand. I had tried OPKs (ovulation predictor kits), and found them to be too difficult to understand. Is that line the right color, or should it be darker … does this mean I’m fertile NOW or in a few days … and so on. The Clearblue Easy Fertility Monitor took ALL of the questions out. Even though we weren’t so lucky as to get pregnant on the first try, we knew that our timing was perfect and it was only a matter of time.

    I just had to chime in and say I agree! 🙂

    Oh, and congratulations on the pregnancy! <3
    .-= Heather´s last blog ..Winner Announcement =-.

    1. Oops, I forgot to check the box to notify me of replies. LOL Sorry!
      .-= Heather´s last blog ..Winner Announcement =-.

    2. Thanks for your additional confirmation and insight, Heather! And thanks so much for your well wishes with the new baby…we’re excited! 😉

  3. Please note that I am posting this comment on behalf of reader Sarah who was not able to post it on her own due to an internet filter and the word “sex” :).


    I just wanted to add my two cents worth to the conversation. In terms of conceiving (and avoiding for that matter), Creighton Model Fertility Care (CrMS)is a less expensive option than the Clear Blue Monitor in most areas (for those who cannot afford several of those test sticks) and also has documented that using the CrMS is extremely accurate in finding days of high fertility. In couples of normal fertility 76% achieved pregnancy within the first month, 90% by the 3rd month and 98% by the 6th month.

    There is also the possibility of false reads from the monitor. I know of a personal friend who has been using the CB Fertility monitor for a while so they time relations around when the monitor says she is fertile. However, she has mentioned to me that her mucus dries up before the monitor tells her that she is of “peak” fertility. And we all know that you can’t conceive without the presence of cervical mucus. I know there may be several issues in this particular case, but I just wanted to put it out there.

    There are far less expensive ways of achieving pregnancy than using the CB Fertility Monitor. And I will state that I am completely biased. I do not trust fertility monitors over my own observations or even in conjunction with my own observations.

    I do know that the Marquette model has given many couples (especially postpartum) an added “safety feature” in using the fertility monitor. But I also know the method is not for me and my husband mainly because I trust my own observations.

    Honestly, IMHO, with the knowledge of the shared fertility between wife and husband using NFP, I see the fertility monitor as a complete waste of money.

    Again, just my two cents.

    1. Thanks for the great comment, Sarah!

      I totally respect and understand your position. The Creighton Model is mucus-observation only, correct?

      We actually use the Couple-to-Couple League (CCL) approach now, which is sympto-thermal (mucus + temperature). It’s been great for us for 5+ years, and we have no “need” to add a fertility monitor into the mix. In fact, we conceived all three of our children within two months of trying using only our CCL approach.

      However, we are interested in trying it out in conjunction with our current method with the hope that it will provide additional confirmation or perhaps reduce our Phase II (abstaining) time when we are trying to avoid pregnancy. If I understand it correctly, the Marquette Model actually only uses the monitor as a supplement, so it would include mucus+temperature+monitor (typically for 10 days each cycle).

      I think the majority of those reading this review will be interested in using the monitor for achieving pregnancy outside of the practice of natural family planning. But for those using NFP, I think this discussion is awesome! 🙂

      1. Dustin – From what I’ve been reading about the new Marquette study it looks like they are making Marquette Model literally only the monitor. The study puts you in one of two groups… mucus only or monitor only. That’s certainly not the way it’s always been. When we learned the method 6 years ago it was mucus+temp+monitor. The combination of all 3 was one of the main reasons we chose Marquette over other methods. But, from what I’ve heard from study participants it’s pretty much impossible to go monitor only after you’ve been charting mucus and temp.

        1. That’s really interesting, Angela. I haven’t yet delved into their site, but the “third-party” descriptions I found give the mucus+temp+monitor approach. I’m sure they are doing the study to see if they can go monitor-only since it seems so much simpler. From what you’re hearing, though, perhaps they aren’t going to find that it’s the way to go.

          1. Clarification from a Marquette Method trained nurse instructor:

            The Monitor alone does not give an early enough warning of the beginning of the fertile window for purposes of avoiding pregnancy, and it is possible that in some cycles it will not detect the LH surge.

            So, it is never used alone! In the monitor only group, there is an algorithm as well, based on past cycles, so that you start abstaining on a certain early cycle day, independent of data the monitor is giving you.

            In my opinion, it is highly valuable for a couple to have knowledge of the woman’s biological signs of fertility (mucus/temp. especially). Marquette gives women this option with excellent education. A couple can add the monitor if they would like for increased confidence, especially in special circumstances such as postpartum. It is not necessary though, as mucus only method can be as much as 99% effective, and symptothermal up to 99.6% effective. I believe it is good for people to have options! Some people like the fact that the monitor is high-tech and objective. And, some people are put off by checking their mucus. Others have trouble getting an accurate read from their temp.

          2. Thank you so much, Batrice! Your clarification is very much valued, and I appreciate your willingness to always take the time to help myself and the others in this community with NFP-related questions.

            I’m anxious to spend time learning more about the Marquette Model!

    2. I used the Creighton Model of NFP post-partum/breastfeeding from 2 months post-partum (fertility returned at a little over 2.5 months post-partum, with first menses at 3 months post-partum), and had an unintended pregnancy 9 months after my c-section when we were trying to avoid. A pregnancy evaluation confirmed that this was a “method related pregnancy” (aka a method failure pregnancy.) We’d had problems with continuous but variable mucus, meaning 100 straight days of abstinence, and a lot of abstinence after yellow stamps were introduced, because the Essential Sameness Question could not be applied most times due to the variability of mucus. We conceived on a run of 6 dry days (like 0AD, 2×1 sort of days), when it’s supposed to be “impossible.” It was then that I discovered that the efficacy statistics for Creighton do not necessarily apply specifically to women who are post-partum/breastfeeding. The formal studies on efficacy in the Creighton model are, like most NFP and contraceptive studies, based on women aged around 18-44-ish (ie. not perimenopausal or new to cycles), and in regular cycles of between around 22-42 days, with no known fertility issues. This is standard, of course, but I hadn’t realized that efficacy for my specific sub-group (breastfeeding women in the initial post-partum cycles) may be different. There is one Creighton study that I’m aware of that did look at this subgroup, and it found 100% efficacy with perfect use, but only 80% efficacy with typical use. That’s a wide gap. It might reflect greater difficulty in achieving correct and consistent use over the method, and that would jive with my experience. We did manage to use it correctly and consistently, but not everybody might handle such long extended abstinence with fertile signs that cannot *ALL* be actually fertile. People in those circumstances, with confusing mucus presentation and excessive abstinence, may begin to take chances because they no longer believe or trust what the method is telling them about their fertility.

      Anyway, after this experience, I switched to Marquette, where I knew that the 98% efficacy statistic for avoiding pregnancy was specific to my current situation (post-partum/breastfeeding.) Prior to cycle return, I was using a test stick a day, which cost me about $35 a month. After cycles returned, for the first 6 cycles, I used about 15 test sticks a month, when ovulation was delayed and the luteal phase short. After cycles had returned to a more regular pattern, I used about 8-12 sticks per month, for an average cost of about $10-12 a cycle.
      I consider that cost to be reasonable, although we had to make sacrifices to afford it. I believe the cost for regular follow-ups with an FCP varies, so I can’t make a reliable comparison.
      Oh, and I should mention I purchased the monitor used on eBay for about $80, so that was my initial start-up cost. It’s ok to purchase a used monitor, but you will need to do a hard reset or reprogram the monitor to clear the memory, as you don’t want it operating on the prior user’s hormonal data.

      Marquette offer a variety of protocols. The “monitor alone” protocol is actually the monitor along with a default rule for abstinence (for those without 6 regular cycles worth of data), or the algorithmic rule (for those with at least 6 regular cycles worth of data.) The only time the monitor is genuinely used alone is for post-partum women in “cycle 0”, prior to the return of cycles. In that use, it was 98% effective in avoiding pregnancy. The researchers found that for the post-partum/breastfeeding group of people, using monitor+mucus (plus any applicable rules) did not increase efficacy, although it seemed to increase abstinence, and in fact seemed to decrease efficacy. Reasons for this may be that people were using mucus to “trump” the monitor or default/algorithmic rule for abstinence, in order to reduce abstinence. Typically, a cross-check is used to increase conservatism. That is, if the monitor reads low, but you see fertile mucus, you begin abstaining. But it may be that people were using mucus to decrease conservatism… so the rule saying to begin abstaining, or the monitor reading high, but not seeing fertile mucus so not abstaining.
      I personally know one person who did this. She was also a prior Creighton user, but had switched because she had a yellow-stamp pregnancy. I don’t know if it was a user related pregnancy or a method related pregnancy. Marquette’s default rule said that in her second full post-partum/breastfeeding cycle she should begin abstinence on cycle day 9. She got a high reading on the monitor on day 10. But on days 9-11 she did not observe any fertile mucus, so thought it was impossible to conceive. She had sex on day 11, and conceived from that act. I’m wondering if the higher pregnancy rate for people using monitor+mucus is due to that sort of thing? I’m not sure. I wonder if the researchers did an analysis of it.

      The other protocols Marquette offers, in addition to monitor “only” and monitor+mucus are ones that incorporate temps. You can do monitor+temps, mucus+temps, and monitor+mucus+temps. These are not all reflected on the public website, but the Marquette forums or an instructor can take you through them, and the waiting-to-be-released new charting website and app provide for all of these possibilities.

      I did want to say that there shouldn’t be any “false reads” with the monitor, barring situations where tetracyclines are being taken, or the woman is pregnant (the monitor will read hCG as LH), or fertility meds are taken, etc. The monitor otherwise will accurately reflect the estradiol and LH levels in the urine, and those accurately reflect serum hormonal levels. That’s proven. It can be that some women experience what is called “false peaks” but are actually what is better termed “practice peaks”. That is, their bodies do have elevated estrogen and LH levels, both of which are needed together to trigger a peak reading, but the ovulation attempt is unsuccessful. It’s a true peak, but not one that leads to successful ovulation. This is a bit of a terminology problem. Women with PCOS are advised to work with an instructor if using Marquette, as they can be prone to frequent LH rises before a successful ovulation.
      In Sarah’s friend’s case, it seems her mucus peak preceded actual ovulation by a day or two? That’s not uncommon. Creighton allows for a mucus peak that comes =/- 2 days of actual ovulation. As with all fertility tracking tools commonly in use, they provide a window for ovulation, not an exact pin-pointed day. It’s the same with Marquette. It too has a window for ovulation, where almost all ovulation occurs on the two days of peak or the high day following peak. For those trying to conceive, that’s why it helps to have intercourse on the days of monitor high preceding peak – or for mucus based systems, on the days of fertile-but-not-peak-type mucus preceding peak, as well as on peak days.

      Obviously, Sarah’s and my differing experiences are just that. Individual anecdotal accounts. I will say that after I stopped breastfeeding, my mucus presentation became far more readable and useful, so that it basically tracked what the monitor was telling me. I ecologically breastfeed, and for longer than the norm (15 months, and 3.5 years with my two older children. My current is only 5 months old and I don’t know how long he’ll continue nursing), and since mucus is not a reliable indicator of fertility for me for long periods of time, I’m thankful for the monitor and the Marquette Method that allows an effective use of the monitor to avoid pregnancy! And honestly, once my mucus returns to “normal” again after this baby weans, I have no plans to use it for NFP decision-making purposes. One of the great benefits of using the monitor-only protocol (monitor+default/algorithmic rules) or the monitor+temps protocol is that intercourse is available any time of the day in all phase 1 days (as soon as you’ve tested that morning if it’s a testing day.) Since my husband starts work in the afternoons, that gives us the potential for intimacy in the morning or early afternoon, instead of having to wait when he’s come home at night, and we’re both exhausted from work and child-wrangling. It also means days of menses bleeding are all available too, although we don’t use those so frequently.

  4. Wow- thanks for posting this and for all the comments! I have heard of this monitor before, but never looked into it. I am so intrigued by the NFP methods/teaching and so fascinated by all of it! Haha! I’m actually more interested at the moment in the preventing pregnancy portion, as my fiance and I are definitely not ready for babies! 😉 Could the above mentioned NFP method using the monitor as a supplement be just as useful and ACCURATE for preventing pregnancy as for planning it?

    Thanks again! LOVING these discussions! Our bodies are so crazy-fascinating! 🙂

    1. Absolutely it is! We’ve been using it for 6 years (5 married) and wouldn’t be doing NFP any other way.

      Check out Marquette’s website – which I’m sure Dustin linked to above. They’re actually still looking for people to participate in their study (but you could be put in the monitor group or the mucus only group, I think it’s totally random).

    2. NorCalRN,

      If you haven’t spent time looking into Natural Family Planning (of which the Marquette Model is one approach), I’d strongly encourage you do so. I have written quite a bit on this site, and I’d also suggest checking out the resources on another blog:

      To answer your question, we’ve used NFP (CCL method, no monitor) for the past 6 years and spaced our children *exactly* as we had hoped. When practiced well, these methods are every bit as effective as any artificial birth control.

      Plus, if you are an RN as your name suggests, you should be all over this stuff! 😉

  5. Dustin ~ Out of curiosity, have you read “Taking Charge of Your Fertility” – it’s the book for FAM (Fertility Awareness Method), which is pretty similar to NFP. It’s what we used in trying to conceive (with the added help of the monitor), but weren’t so successful with AVOIDING pregnancy! LOL (It’s the self-control required during the fertile period that did us in! 😉 )
    .-= Heather´s last blog ..Winner Announcement =-.

    1. I have not read that particular book, but I’d like to someday just for the added perspective. I am familiar with FAM, which is basically a secular version of NFP that “allows” for the use of artificial contraception during fertile periods. That part of it doesn’t fit with our beliefs, so it wouldn’t be for us.

      However, even if we were fine with contraception, I don’t really see the wisdom in using it when you *know* you are highly fertile if you really don’t want to conceive a baby. Contraceptives fail, so using them when failure could very likely result in pregnancy doesn’t seem so wise. Is that what happened in your case or were you going “no contraceptives” but just didn’t make it through the abstaining days? 🙂

      1. It was the latter – just not being careful enough. Neither of us liked the contraceptives, and I think that’s why we didn’t use anything. I was still nursing my son, so I (obviously) wasn’t on anything – and wouldn’t be. I hated the pill. For what it’s worth, I wouldn’t change a thing – our youngest is such an amazing, wonderful little girl! 🙂

        I didn’t realize that the use of contraception was the main difference between NFP and FAM. I was asking more simply because of the similarities between what I knew and what I saw you mention above.
        .-= Heather´s last blog ..Testing a Music Feature =-.

        1. The science that FAM and NFP are based on is the same. When FAM users use barriers, however, the actual effectiveness of the barrier is less than advertised if they only use them during the fertile time. The effectiveness of any barrier is based on an average over the entire menstrual cycle.

          It is an excellent book–it was part of my course materials as I was training as a Marquette Model instructor. Weschler goes into a lot of depth explaining different circumstance/charting patterns from the norm. So, it is a very helpful resource book for me.

          1. Batrice, I’m curious about this statement:

            “When FAM users use barriers, however, the actual effectiveness of the barrier is less than advertised if they only use them during the fertile time. The effectiveness of any barrier is based on an average over the entire menstrual cycle.”

            It’s true that the effectiveness of barrier methods is based on the average over menstrual cycles, usually over 12 months of use. However, barrier method failures are not considered things like breakages, or other failures, but are calculated in pregnancy rates, just as for any other family planning method failure rate. Only a pregnancy is considered a failure of the barrier contraceptive.
            Given that, condoms will only fail during fertile times anyway. It would be possible – if we had that information, which we don’t – to exclude all the data from people who had intercourse during infertile days elsewhere in the cycles and still end up with the same result. So the rate of condom failure for general users (using them as contraceptives through the entire cycle) and for FAM users (using them as contraceptives through the known potentially fertile times of the cycle) should be similar. If the condom use is going to fail, it’s going to fail in the fertile time. Whether one uses them only in the fertile time, or all the time, the failure rates should be about the same.
            Someone may wonder if the efficacy of condoms is artificially inflated by testing throughout the entire cycle, since some people may not have intercourse during the fertile phase in some cycles. This should not be the case, as any decent study large enough to provide reliable results will give an accurate efficacy rating, despite the blips in some people happening not to have intercourse during the fertile phase some cycles, and others having intercourse every day during the fertile phase in some cycles, etc. A reasonably large study will make these individual quirks harmless to the overall determination of efficacy. Same goes for NFP studies, too. Some women may have a long/anovulatory cycle, but the efficacy stats should still stand, if the study is large enough to account for such a quirk. It shouldn’t artificially inflate the efficacy rates of NFP because some people don’t ovulate every month over 12 months of use.

            I do wonder if most general condom users who are not fertility tracking don’t end up having intercourse during the fertile phase pretty reliably anyway, given research about male and female attraction/desire levels during the woman’s fertile phase.

            Anyway, there is an excellent study out of Germany that compared the use of NFP with the use of FAM for STM. It can be found here:

            Tables VI and VII are particularly relevant, but the whole article is a fascinating read.

            I use NFP for religious reasons, so have no vested interest in promoting it as significantly more/less effective than FAM, because it doesn’t matter to my choice whatsoever. Even if FAM were *more* effective, I would not be using it! I am interested in the accurate presentation of efficacy, in general, however, because I’m one of those aberrant individuals who enjoy stats. ;-p

  6. Pingback: Basal Body Temperature – Should You "Temp" for Fertility Signs? | babyguga
  7. Angela- Thanks!! That is super helpful to know. I’m actually very ready for pregnancy, but my fiance is NOT. Not only is he an Engineer (so needs the % and stats of birth control pills to trust their effectiveness) but he is super paranoid about getting pregnant on “accident”. We’ve been together for 8 years, so like I said- I’m ready. 🙂

    Dustin- I AM a Nurse, and have always been super fascinated by the reproductive systems and how intricate and amazing our bodies really are. I’m also an advocate of Homebirth and Natural birthing methods, so going hormone-free and natural with family planning and “prevention” Totally appeal to me!! I’m LOVING all this info!

    Batrice- How can I get more info on becoming an Instructor?? That really appeals to me too, for the future. 🙂 I’m not Catholic though; does that matter?!

    Thanks Guys!
    NorCalRN aka Erica 😉

  8. don’t really see the wisdom in using it when you *know* you are highly fertile if you really don’t want to conceive a baby. Contraceptives fail, so using them when failure could very likely result in pregnancy doesn’t seem so wise.

    tahx for all

  9. Help with Clearblue Fertility monitor’s testing window.

    say my bleeding started today afternoon at around 1 o’clock,I understand that Ineed to press m at around 6o’clock tomorrow morning.

    Do I need to adjust testing window at the same time or its automatically set once I pressed ‘m’ on the monitor.

    1. Hi Raaji,

      I’ll defer to Clearblue’s instructions for an official response. However, the way we’ve done this is to press “m” the following day during your testing window as you said, and this sets the time of the testing window. If the bleeding is light the first day, we just leave it as Day One the next morning. If the bleeding was heavier, we hold down “m” until the “2” shows, which means you’re telling the monitor it’s actually the start of Day Two of your cycle.

      I hope that helps!


  10. Hi Dustin,
    I was just wondering if you all are still using the Clearblue Monitor. I am currently pregnant, but after our baby is born, I was interested in trying out the Marquette Method to avoid pregnancy for awhile. I like the cross-check of the monitor, but it does seem like an expensive purchase, so I want to get as much feedback about it as I can first. Did you just read the “quick instructions” on the website in order to get the method down, or did you go to other resources as well. Thanks for any input that you might have!

    1. Hi Jenny,

      Yes, we are still using the monitor and have been very happy with it. It is a pretty expensive purchase, and then there is an ongoing expense since you have to continue to buy testing sticks. However, for us, it’s been worth it.

      We have just been following the instructions that Marquette University publishes on their website:

      Good Luck!


      1. Thank you! I have heard several good reviews about using this, especially in terms of using this method while breastfeeding. I am thinking that the initial expense is worth it.

        1. Jenny – Check out ebay. I purchased my monitor for much less than retail. I also find all my sticks on ebay… usually $30-$35 a box instead of retail.

  11. Can the Clearblue Easy fertility monitor be used by women who don’t get their period but have the symptoms of ovulation every month? If so, how would you start using it if you don’t have a CD1?

    1. Hi Cathy,

      This is a fantastic question, but unfortunately I just don’t have an answer for you. However, I strongly suggest you contact the folks at Marquette University, and I’m sure they will be very helpful in answering your question. You can find them at



  12. Pingback: 10 Awesome Gifts for Married Couples | Engaged Marriage
{"email":"Email address invalid","url":"Website address invalid","required":"Required field missing"}