Empowering Women // Strengthening Families


We have received many responses to our latest article asking about the accuracy of a 6-8 day fertile phase. The questions deserved a thorough response, so a follow up article was in order.

As a Billings Ovulation Method™ Instructor, I believe that the Billings Method is the most accurate, most researched, and the best method of NFP available. Every NFP teacher (of any method) should be able to tell you that their method is the best and be able to explain why. If they cannot, they shouldn’t be teaching it. That being said, when we first started charting, we used a different method. On the advice of our NFP instructor, we decided to switch to the Billings Ovulation Method™.

We found in Billings what my husband calls the “NFP trifecta.” It ranks highest in three categories that were of utmost importance to him:

  1. Studies show the “actual use efficacy” of the Billings Ovulation Method™ is 99.5%, higher than any other method.
  2. With only 4 rules, and no devices or burdensome rituals, Billings is the simplest method.
  3. Because Billings’ science recognizes the individuality of each woman, it offers the most available days for intimacy of any NFP method.

Billings differs from other methods of NFP, in that the method never identifies “fertile type mucus.” Rather, the method pinpoints patterns of infertile discharge for each individual woman. Every woman is unique, and signs of fertility can differ significantly from woman to woman. The nearly one million biological tests done by The Billings Ovulation Method™ have taught us that fertility can still be determined with accuracy without assuming that every woman must experience the exact same things. This research, and the way Billings’ determines potential fertility, opens up more days for intimacy in the follicular phase than other methods.

Furthermore, Billings’ extensive research makes a woman’s chart a diagnostic tool, useful beyond simply determining daily fertility. Hormonal imbalances, vitamin deficiencies, insulin resistance, and early signs of reproductive cancers can all be detected on a Billings Ovulation Method™ chart.

With this foundation, let’s address the 6-8 day period of abstinence referenced is our previous article. Recent research suggests that the final process which develops a follicle to maturation immediately preceding ovulation should only take up to five days. In a cycle displaying fertility longer than five days, something is delaying follicular maturation. Dr. Mary Martin, founder of the Billings Center for Fertility and Reproductive Medicine, says, “There [is always] a reason why women don’t ovulate normally, have intermenstrual bleeding, have pain or infertility.” A competent, trained Billings Method instructor should be able to help a woman either identify the underlying reasons or to provide a starting point for the woman to discuss with her physician. Some underlying issues can be fixed easily by correctly identifying infertile mucus, starting certain vitamin regimens, and changing habits. However, if a client has a chart that is indecipherable, a teacher should never wait longer than 3 cycles before referring them to a medical professional that can help them identify and treat the reasons for the hormonal imbalance. An NFP teacher should never leave a woman uncertain for months or years a time.

While delayed follicular maturation is not the end of the world, we should always be working to help our clients obtain optimum reproductive (and marital) health. It is also possible that what may simply look like delayed follicular maturation, is in actuality a sign of something more serious. Billings alone has the research behind it that can help a woman identify these issues.

6 to 8 days of potential fertility may seem, based on your experience, to be a pipe dream — but while every woman is different, and while charts can differ from month to month, The Billings Ovulation Method™, taught by competent, certified teacher, will help you identify your true fertile phase. If you periodically have longer fertile phases, don’t worry about it too much. But If you consistently have fertile phases longer than this to the point that it has become burdensome, you should know that you have options. It may take a little time, but a good teacher can help you regulate your cycle so that you can enjoy NFP without unnecessary abstinence.

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8 Responses to 6-8 Days. Are You Serious?

  1. I am a huge fan of Billings and it does identify my fertile time more narrowly than any of the other methods I have tried. I do have a question on the math though: is 5-7 days meant just for older women? I would think that a healthy 22 year old would be dealing with at least 10 days of abstinence due to accounting first for sperm life and then for 3 days of BIP. Am I missing something?

    • It is wonderful to hear of your great experience with Billings. 5-7 days is not just for older women. For any woman, a 10 day period of abstinence would be more than “average.” If the right discharge is present, sperm can only be kept alive for up to 5 days. As we mentioned in the above article, science is suggesting that maturation of the follicle should only take up to 5 days. Adding on the three days after peak to ensure ovum disintegration would still only account for 8 days of abstinence in this case. Every chart is different, and if the fertile phase is longer than this, nothing is necessarily wrong, it’s just longer than science suggests should be necessary.

  2. Thanks! It feels like there are so many variables that the promise of only 5-7 days sets young couples up for unnecessary disappointment, but if this is what you see as standard for the couples you teach, that is fabulous! Do you know of any studies on the actual average length of identified fertility for Billings users? Sort of like the fertile time for STM users averaging 13 days per cycle? http://humrep.oxfordjournals.org/content/early/2007/02/20/humrep.dem003.full.pdf

    If this is an actual Billings-wide stat then I know many, many couples who would suddenly be very interested in switching methods. Yes, I know that Billings is superior for a number of reasons, but those don’t seem of interest to many people I know. 🙂

  3. This article makes a few assumptions that I think should be clarified:

    1. The “5-7 days” does not count abstinence from “red stamp days” at the beginning of the cycle.

    2. 5 days follicular development/sperm life + 3 days BIP = 8 days total.

    3. The article assumes that the hormonal imbalances can be identified and treated. That’s not always so simple.

    That being said, the Four Rules are conservative. Lyn Billings said that “The guidelines have been formulated for maximum security”. So, if couples don’t have to be quite so conservative to have the method remain highly effective once they get experience or if I’m missing something, then that would be significant.

    We are big fans of Billings, but I agree with Rae that overselling any method sets couples up for disappointment.

    • I don’t believe we’ve made any assumptions, though we did misspeak on one of the points, and we’ll make corrections for future readers. Below are a few clarifications.

      1) We did mention in the article that 5-7 days does not include bleeding days. But when following the rules correctly, it is important to remember that only certain “red sticker days” require abstinence, they are not universally off limits according to the genuine BOM.

      2) We stated that the science suggests, in a cycle of optimum reproductive health, the follicular maturation should take no longer than 5 days. Sperm can only be kept alive for “up to 5 days” if certain discharge exists at the time. Sperm life has little to do with why the rules are applied. I did realize that when I first mentioned 5-7 days I was not including the +3 after peak. We are changing our articles to better reflect the window which can be at minimum, 6 days, but in a perfectly healthy cycle should be no more than 8 days.

      6-8 days of average fertility (in a cycle of optimum health) is correct, and we are correcting the articles to reflect this. We do apologize for any misrepresentation in this regard.

      3) Hormonal imbalances always show up on a Billings chart. As teachers we are trained to identify them simply as “your chart is showing signs of low progesterone” or “estrogen dominance.” We are able to suggest simple vitamins or changes in habit that might help. We as teachers cannot diagnose what is causing the imbalance, but we can and should give the client a starting place to consult with her physician in order to figure out what is going on. It is the doctor’s job at that point to diagnose and treat the imbalance. One of our current researchers, Dr. Mary Martin, is an expert in diagnosing these disorders. She has discovered that hormonal imbalances that affect ovulation are caused by 1 of 5 “normal” things, and the possibility of 2 extraordinary things (like cancer). The most common causes can be treated and corrected in most cases quite easily.

      Because of the variance between women (and between an individual woman’s cycles), We don’t ever average or tell a woman what she should expect out of her cycle. What we do suggest, and the science agrees, is that the process of follicular maturation in a perfectly healthy woman should be between 6-8 days, and the luteal phase should be between 11-16 days. We know that many women may vary from these numbers, but also want to give them hope that if they do vary wildly from these numbers for an extended period of time, they should see their doctors to correct the problem.

  4. Rae: The study you cite about the Symptothermal method says the following:

    “One has to realize that the median fertile time determined by the STM is 13 days a cycle (less days after the first year). The potential fertile time is in fact longer than the actual physiological fertile time.”

    The method in the study is MUCH more conservative than the Billings Method in determining the fertile period, except for allowing intercourse on the evening of Peak +3 if there was a thermal shift. It contains no provision for a “Basic Infertile Pattern”.

    The study also recognized that many of the couples who used a fertile day had figured out that their actual fertile time was less than that calculated by the method. This is what accounts for the low pregnancy rate among couples who did not stick to the method.

    The study was also limited to women with regular cycles who had an established thermal shift.

    One of the goals of the Billings Method was to determine actual fertility with as little margin of error as possible. Another was so that it could be used by ALL women, not just those with regular cycles.

    So if Billings can better cut down to the actual physiological fertile time, then that is significant. But the flip side of this is there is no margin of error.

  5. Thank you for your clarification. That makes a lot more sense.

  6. To clarify, I wasn’t suggesting that Billings should have the same amount of days identified as fertile as STM, I would expect Billings to be at least a few days less. I was offering the link as an example of the sort of method-wide average that I am interested in.

    I had thought it was significant that Billings examples tend to show around 9 days in a row which would require abstinence to avoid pregnancy, and if 6-8 days is actually the standard for BOM, then it might be helpful to nudge the powers that be to update the basic information so that it reflects what is standard.

    I still don’t understand how 6 days could be considered to be healthy rather than a sign of reduced fertility. After all, wouldn’t it mean for a couple seeking conception that they would only have 2 days of fertility prior to ovulation, plus the day of ovulation/possibly a few hours after?

    And this isn’t directly related to the post, but I would love it if you wrote another post about Billings health resources. In the past I was only able to find out about maybe 2 BOM specialists in the US? I can’t remember precisely since whatever I found wasn’t on the East Coast. Thanks for all of the work which you are putting into getting this great info out there!