Breastfeeding and return of fertility in natural family planning studies

During the postpartum period of time, fertility is in a unique state. For those fully breastfeeding, it may be months or years before they begin ovulating again regularly and with fertile cycles. This article talks about some of the data we have on what return of fertility looks like. This information may be of particular interest to those charting with a method of natural family planning or fertility awareness. Charting at this time may be difficult, and for highest efficacy should be done closely with a certified natural family planning educator.

Breastfeeding as Birth Control

Breastfeeding has been shown over numerous studies to have an effect on return to fertility and ovulation. Kennedy et al (1989) reviewed 10 studies from multiple countries to come to a consensus on what full-breastfeeding means.

  • Fully breastfeeding or at least partially fully breastfeeding
  • Fully breastfeeding meaning the infant gets all or as close to all as possible of their nutrition by suckling at the breast directly, no bottles or pumping
  • Small bites of regular food or water do not disqualify for full breastfeeding
  • No bleeding past day 56 postpartum until the 6 month mark postpartum.

Some methods suggest going no longer than 6 hours at night without breastfeeding. While this was not mentioned in the study, it is generally used as the standard in fertility awareness based methods to see if someone qualifies to rely on the lactational amenorrhea method (LAM).

LAM is 98% effective for avoiding pregnancy when all criteria is met up until 6 months postpartum. After that, efficacy drops precipitously.

What about ecological breastfeeding?

Ecological breastfeeding requires even stricter criteria and may delay fertility for much longer. Bleeding past day 56 does not disqualify someone for ecological breastfeeding. Ecological breastfeeding should not be confused with LAM! Ecological breastfeeding was coined by Dr. Sheila Kippley. You can buy her book here.

The criteria include:

  • Breastfeed exclusively for 6 months
  • Pacify your baby at your breast
  • No bottles or pacifiers
  • Sleep with your baby for night feedings
  • Sleep with your baby for a daily-nap feeding
  • Nurse frequently day & night. Avoid schedules.
  • Avoid anything that would separate you from your baby / prevent regular nursing

Symptothermal Method Studies on Breastfeeding

For the first part of this overview, I am going to cover a few symptothermal studies that followed breastfeeders from birth to return of fertility. Symptothermal charters record cervical mucus and basal body temperature daily in order to track their fertility and determine when the fertile window is opened and when it is closed.

In “Breastfeeding and the Symptothermal Method,” Kennedy et al. followed 73 women who charted with a symptothermal method in Australia, Canada, England. While this is a small sample size, the team collected a ton of data: 22,538 diary sheets, 9,428 urinary vials to measure hormones, and 1,600 follow-ups with the women (Kennedy 1995).

Kennedy et al. reported the following data regarding the wait to return of fertility:

  • Only 25% of first ovulations postpartum had “adequate luteinization.” This means over three quarters of first ovulations were likely infertile (Kennedy, 110).
  • In retrospect, up to 51% of possibly fertile days identified by sympto-thermal would not have lead to conception (Kennedy, 112). The study standard for this was 5 day sperm life.
  • They found that 94-99% of the time, the sympto-thermal method correctly identified when a day was really infertile. This means that around 1-6% of the time it didn’t identify a day that may have lead to pregnancy (Kennedy, 112).
  • They recorded four adequate ovulations with those fully breastfeeding for their first ovulation. This was defined as a 10 day or greater luteal phase with adequate progesterone levels. (Kennedy, 112).
  • Abstinence was expected per the rules for about 50% of the charted days included in the study (Kennedy, 113).

Bonus Information for Cervical Mucus Fans: Fertile mucus in this study was considered anything cloudy, opague, clear, translucent, stretchy, strands, wet, lubricative, moist, or unusually abundant.

Zinaman and Stevenson in the USA followed 25 women until they had 3 ovulatory cycles postpartum (1991).

They found the following data regarding return to fertility:

  • 20% of ovulations in the first ovulation postpartum during the first 6 months were considered fertile (ie a luteal phase longer than 10 days) (Zinaman and Stevenson, 2037).
  • Basal body temperature appeared inadequate to capture the first ovulation, occurring up to 4 days after the LH peak, but it improved in later cycles (Zinaman and Stevenson, 2037).
PercentageTime to Return of Fertility From Birth
25%Less than 200 days 
25%200 to 300 days
35%301 to 400 days
15%More than 400 days
Time to return of fertility among 25 breastfeeding women in Washington, DC. Created from page 2037 in Zinaman and Steveson (1991).

In an article in the International Review of Natural Family Planning, Parenteau-Carreau presents data collected from 43 postpartum women charting with the Serena Canada method.

Parentau-Carreau reports the following data on postpartum charting:

  • 65% of first bleeds were preceded by a thermal shift (35).
  • The collection of charts confirmed the theory that 4 high temperatures should be used postpartum, as there were instances of 3 raised temperatures that were not true shifts (36).
  • Among temperature shifts during the first 6 months postpartum, 75% lasted 8 days or more (37).
  • For babies who sucked their thumb or used a pacifier regularly, their mothers experienced return of fertility an average of 13 days earlier than those who only breastfed for soothing purposes (37).
  • The basal body temperature curve tended to become more steady or regular in the one to two weeks prior to the first ovulation (38).

What can we conclude from all this data?

  • Breastfeeding and meeting the criteria for LAM is highly effective for avoiding pregnancy in the first 6 months postpartum.
  • Most first ovulations postpartum are infertile (defined as a luteal phase less than 10 days long).
  • It is possible to chart during postpartum to avoid pregnancy.

What methods work best postpartum?

I recommend practicing either the Billings Ovulation Method or Marquette postpartum. I do not recommend sympto-thermal method because temperatures are not useful until fertility returns. I only recommend taking your temperature before the 6 month mark to those who are not breastfeeding. In addition, the sympto-thermal method offers less complex mucus patterns than Billings does.

Billings Ovulation Method involves charting sensation at the vulva and appearance of mucus to create a basic infertile pattern. It allows only alternate evenings of the basic infertile pattern for sex until return of fertility (IE ovulation) occurs. It is approximately 98% effective with correct use postpartum.

  • Subjective fertility signs (sensation and appearance)
  • Only alternate evenings for sex
  • Very affordable (Billings will work to set you up with a free instructor if you absolutely cannot afford one)
  • No re-occurring cost
  • One-time cost for instruction (ideally, please pay your educator if you can! Some instructors may charge after 1-2 years pass)

Marquette Method involves charting urinary hormones using the Clearblue monitor. This monitor reads estrogen and LH levels. This method is going to be more expensive than a cervical mucus only method, so I only recommend it to those who can afford approximately $30 USD a month or more postpartum. Unfortunately, the stick costs fluctuate up to $50 USD or so for 30 sticks, but I have seen them as low as $30 USD. Marquette is approximately 98% effective with correct use.

  • Objective fertility signs (monitor does the reading for you)
  • Any time of day sex when available
  • Expensive by some standards. Sticks cost twice as much in Europe. May not be available in some countries at all.
  • Re-occurring cost
  • One-time cost of the monitor ($50-$130 USD depending on if buying new or used)
  • One-time cost of instruction (unless you go over the year mark, you may need to pay twice)
  • I have heard that some instructors may offer scholarships, but you would need to contact individual instructors or organizations to learn their policies.

References

Kennedy, K; Rivera, R; McNeilly, A. (1989). Consensus statement on the use of breastfeeding as a family planning method. , 39(5), 0–496. doi:10.1016/0010-7824(89)90103-0 

Kennedy, K., Gross, B., Parenteau-Carreau, S., Flynn, A., Brown, J., & Visness, C. (1995). “Breastfeeding and the Symptothermal Method.” Studies in Family Planning, 26(2), 107-115. doi:10.2307/2137936

Parenteau-Carreau, S. (1984). “The Return of Fertility in Breastfeeding Women.” The International Review of Natural Family Planning. Vol. 8(1). pp. 34-38.

Zinaman, Michael; Stevenson, Wilma (1991). Efficacy of the symptothermal method of natural family planning in lactating women after the return of menses. American Journal of Obstetrics and Gynecology, 165(6), 2037–2039. doi:10.1016/S0002-9378(11)90575-4 

No dry days? You may qualify for a basic infertile pattern!

After menstruation, the majority of women will experience dry days. For these women, their basic infertile pattern is dry. Other women may experience a pattern of unchanging mucus, sensation, and discharge after menstruation. For women who experience this same UNCHANGING discharge, mucus, sensation pattern for three cycles in a row following menstruation, they may have a non-dry basic infertile pattern. The keyword here is unchanging; any changing pattern would not indicate a basic infertile pattern. This type of pattern should only be established under an instructor if someone is seriously avoiding pregnancy. For women who establish this pattern with a mucus-only instructor (either Billings or Creighton are options), this pattern has the same level of efficacy for avoiding pregnancy as a dry pattern. Some examples of this pattern may be continuous moist days, continuous sticky days, continuous white mucus, or others!

DO NOT try to use these days for unprotected sex without establishing it for a minimum of 3 cycles with an instructor (it may take longer than this). When using these days, intercourse should be rotated to every other day in the evening before bed. 

What causes this pattern? In cycles less than 35 days, it is caused by bits of the G mucus plug breaking off. While the plug is breaking off, it causes the visible mucus or sensation. However, the rest of the plug is still blocked. This means this time of the cycle can be considered infertile if an instructor works with you to make sure it is the G mucus plug breaking off. In cycles longer than 35 days, it can be caused by a combination of the G mucus plug breaking off and estrogen’s effect on the vaginal walls causing a sloughing effect. Read more about the types of mucus here.

Sympto-thermal methods like Taking Charge of Your Fertility also mention a “sticky” dry basic infertile pattern. Methods like SymptoPro claim that women do take on an elevated pregnancy risk when using these days. As sympto-thermal methods are not as strenuous on mucus observations as mucus-only, consider this risk when deciding to utilize this pattern. Again, ideally if someone is avoiding pregnancy, they should reach out to an instructor before using these.

In either of these cases, experiencing any dry days following menstruation means that you do not qualify for a basic infertile pattern of non-dry in regular cycles. This pattern needs to be re-established with an instructor following hormonal birth control usage or pregnancy. 

Irregular Cycles

For postpartum, perimenopausal, or people with cycles longer than 36 days, it is also possible to have a basic infertile pattern of non-dry after 14 days of the same UNCHANGING discharge, mucus, sensation. In addition, a combined basic infertile pattern is possible in the Billings Method. This should only be established with an instructor. For these transitions, the Billings Method is highly recommended. 

In both regular and irregular cycles, working with an instructor can help you get more safe days for unprotected sex if you are experiencing a non-dry pattern.

6 Cycle Comparison: Marquette Versus Billings Versus DOT Fertile Windows

Have you ever been curious what your fertile window would look like in multiple methods?

In this blog, I show 6 cycles with various fertility signs and method interpretation including: the sympto-thermal method (Sensiplan rules), Marquette method, the Billings Ovulation Method, and DOT (a calendar method that was recently purchased by Clue app and is a new FDA approved birth control). I chose to include representation for only studied methods of fertility awareness: sympto-thermal, sympto-hormonal, mucus-only, and calendar method.

All charts are from the Read Your Body app, a flexible app for all methods that I highly recommend!

Some things to know before reading:

  • Marquette allows sex any time of day within their rules. My calculation rule lasts until the end of day 7.
  • Sympto-thermal method allows sex any time of day during first 5 days of menstruation, but the first safe day in the luteal phase must be used in the evening. My calculation rule is day 5.
  • Billings Ovulation Method allows sex in the evenings only and on rotated days in the pre-ovulatory time of the cycle. Days of bleeding where mucus cannot be observed are not allowed. However, since you can have sex any time of day post-ovulation with Billings, sometimes cycle day 1 is available if you have sex before bleeding occurs.
  • DOT allows sex any time of day within their rules. It automatically opens my window on day 7.

Cycle 53

Consecutive Fertile Window for Expected Abstinence:

Billings: 8 days

Sympto-thermal: 12 days

Marquette: 12 days

DOT: 12 days

General remarks: This is an extremely standard cycle in length and mucus patch (the average person will have a 5 to 6 day mucus patch when charting). I believe this is a great example of what methods would look like for someone of the average cycle length.

Cycle 54

Consecutive Fertile Window for Expected Abstinence:

Billings: 9 days

Sympto-thermal: 21 days

Marquette: 15 days

DOT: 12 days

General comments: My average coverline is 96.8 to 97.0, so regardless of earlier high temperatures and some illness I felt confident marking this coverline and temperature shift. Due to continous long, clear-ish mucus, my sympto-thermal peak was extremely delayed. Billings is a sensation focused method so I was able to mark my peak at an earlier time and have less expected abstinence.

DOT gave me a very risky day on this one. It is possible I could have been ovulating near the safe day. However, that would have only left 9 to 10 days for implantation and I had spotting, so whether this truly could have ended in pregnancy is up in the air. Even with well-timed sex, pregnancy will not always occur.

Cycle 55

Consecutive Fertile Window for Expected Abstinence:

Billings: 6 days

Sympto-thermal: 12 days

Marquette: 12 days

DOT: 12 days

General comments: This small fertile window in Billings might look scary to some, but it is not possible to get pregnant when the cervical mucus plug is truly closed. I have about one cycle like this every 13 cycles. I was also using the Kegg device during this cycle which is placed internally and reads electrolyte levels to determine the fertile window. It gave me the same 3 day dip for a fertile window, so I feel even more confident that those days were truly dry. I am missing temperatures on this one because my thermometer glitched and would not give me readings on these days. Sex day 1 was allowed because menstruation didn’t start until 5pm.

Cycle 56

Consecutive Fertile Window for Expected Abstinence:

Billings: 8 days

Marquette: 11 days

DOT: 12 days

General Comment: This was an extremely heavy period so I had no period days available in Billings. Even though the other methods gave me available days, I couldn’t have used them due to the pain, so ultimately the other methods didn’t really help out on more safe days.

Cycle 57

Consecutive Fertile Window for Expected Abstinence:

Billings: 10 days

Marquette: 14 days

DOT: 12 days

Cycle 58

Consecutive Fertile Window for Expected Abstinence:

Billings: 9 days

Marquette: 11 days

DOT: 12 days

General Comments: Marquette monitor missed my peak on this cycle. It misses peak on up to 10% of cycles. I relied on meeting LH rules instead of the monitor. Sex day 1 was allowed because menstruation didnt start until 1pm.

Reflecting on What’s Best for Me

I’m currently on cycle 59 charting, and I have tried a ton of methods. Right now, my ideal method is Billings and LH tests as a bonus marker.

While it may appear that Billings gives less safe days in some instances, what is most important to me is having the smallest consecutive fertile window. Having less expected abstinence actually makes me more likely to follow the rules. I was completely unsatisfied with only being allowed period sex in the sympto-thermal method because I have period pain issues. That means that I basically had no safe days at all in reality before ovulation with sympto-thermal.

I originally felt very enthusiastic about Marquette method. However, after 6 cycles of using the Clearblue Fertility Monitor, I realized that it always caught my LH surge after the cheap LH tests. In addition, it missing my peak even once is frustrating for the cost of the product. For that reason, I have decided to stop using the monitor when I run out of tests. I can use a 15 cent LH test and get the period prediction aspect (LH is my most steady indicator).

The DOT app tends to give me a risky cycle whenever I ovulate late and have a shorter luteal phase. I do not rely on this for pregnancy prevention. Overall though, DOT has not given me many risky ways. I use it for long-term period prediction, and it is the most accurate period predictor I’ve ever used for planning months in advance.

What to Consider Before Switching Methods

1. Why are you unsatisfied with your current method? Is it the amount of safe days, or is it the routine that you don’t like?

2. Do you have medical needs that could be addressed by another method?

Sometimes the grass isn’t greener on the other side, but if you are like me and can’t have period sex or don’t want to have period sex, methods like Billings without calculation rules will almost always include more safe days if you are dedicated enough to learn the method and chart it accurately.

Folks in irregular cycles like in postpartum time or with PCOS may benefit from more flexible methods without calculation rules

*DISCLAIMER: DO NOT TRY TO LEARN FROM MY CHARTS. MY CHARTS ARE NOT YOUR CHARTS.

My Experience Becoming a Certified Billings Ovulation Method Teacher

I recently completed my teaching certification for the Billings Ovulation Method through the Billings Ovulation Method Association in the USA (BOMA). This is a cervical mucus / sensation only method that has been taught for over fifty years in over 120 countries.

I began this certification having been quite dissatisfied with my previous certification in the sympto-thermal method. I found the sympto-thermal method inadequate for irregular cycles or postpartum cycles, as well as for any cycles with continous mucus.

This certification 100% cleared up all doubts I had about being able to teach people in these situations! I love that Billing’s motto is “Keep it simple.” Ultimately, this certification gave me the confidence to give up temperature taking as a part of my fertility awareness routine.

First Step:

Before beginning the certification, I took an introductory class with my spouse in the method. This gave me about 6 months to try to apply the principles to my charts before beginning training. I had previously certified in a “Billings-based method” but learned quickly that authentic Billings is a different creature altogether.

I recommend that anyone who is going to train in this method learn to practice it first for at least 6 to 12 cycles under the guidance of an accredited teacher. Joining this program without learning the method first is going to leave you lost on your charts – when you should be confident in your charts before helping others.

Second Step:

The class began in December 2019 and ran through September 2020. We met once a month for approximately an hour (sometimes a little more or less). Inbetween meetings, we were expected to read one to two chapters of material and complete 5 or more worksheets that included chart evaluation and quizzes.

I really appreciated the live classes because my previous certification had no live component. I’m a strong believer that synchronous connection is really important for learning something new.

During class, we were shown PowerPoints and given time to ask questions about the homework. Hearing from long-term accredited teachers about different charting circumstances did wonders for my existing knowledge base. It was incredibly valuable.

Full disclosure: It is important to know that Billings was founded by and is primarily run by Catholics. These meetings often began with prayer or referenced God. Teachers are not required to teach the religious component of the PowerPoint. That means that Billings can be presented in a secular manner. The WOOMB International head organization notably does not include religious elements in their presentation of the method. The science of the method is solid regardless of any ideology attached to it.

Third Step:

The next step after passing an exam on the material was to begin practicum. Practicum is the supervised portion of the certification where you teach 6 to 10 clients minimum in the method while submitting charts and questios to a supervisor selected for you by the organization.

This graphic is how long it took me to finish the practicum portion of the course. Most people take 1.5 to 2 years to finish the program. I went a little faster because I taught larger group classes and had clients lined up before it began.

Practicum was the most enriching part of the experience, and I recommend that anyone who does the training utilize this time to your best advantage. I learned how to help people identify complex basic infertile patterns where they never have dry days. This was not possible in my previous method. I was able to support multiple postpartum women as well as folks with PCOS or who were trying to conceive. I learned so much by meeting with my clients and sending charts to my supervisor.

The follow-ups and classes in Billings are mandatory live meetings (video calling, phone call, or in-person). The follow-ups generally last 15 to 30 minutes depending on the client and how early they are in the process. Follow-ups and classes are required to be live, and this is based on what was done to reach efficacy in the Billings studies. We generally meet with clients seven or more times in the first 6 months, and then every 1 to 3 months. Some people may have more or less follow-ups depending on when they reach autonomy and things like cycle characteristics (postpartum people tend to meet up until the third ovulatory cycle after return of fertility.)

Fourth step:

After having enough clients in different situations (postpartum, trying to conceive, trying to avoid, regular and irregular cycles), I had a final meeting with my supervisor. Before this, I had to compile a document of every client chart. This was a bit laborious as the Billings charts cannot be exported to PDF without losing part of the chart. I had to screenshot segments of the charts and then re-assemble them. This meeting with my supervisor lasted about two hours, and we discussed all of my client charts and any corrections that needed to be made.

Following that, I was recommended for the final step. I recieved a mailed in exam that involved correcting a full paper chart and writing why I made those changes and what mistakes were originally made.

I turned in this exam to two graders. They then met with me and discussed the chart and any necessary corrections. They approved my certification at the end of the meeting.

The Future

Billings Ovulation Method teachers are required to do continuing education to maintain their certification. This is an investment of approximately $300 to $600 every three years. While this is costly, it is really important to attend further training where the teacher can see more advanced charting techniques and learn about health conditions, efficacy, and more!

My Final Thoughts

I would recommend this certification program to anyone who is interested in having an in-depth understanding of cervical mucus charting. The Billings Method teaches about things like the “pockets of shaw” and the cervical mucus crypts. My previous certification did not include close study of the patterns of cervical mucus. This program fundamentally changed my thinking about temperatures always being a necessary part of charting. I ended up dropping temperatures completely after 3 years of using basal body temperature.

Billings allows teachers to order all supplies, including digital materials, for clients. This means I do not have to produce my own materials, and it is super useful for quickly mailing clients what they need.

To make the most of out of this program, I recommend also reading the scientific studies on the side. Unfortunately, the program did not go into a lot of depth on the previous research studies. As someone in academia, I really like understanding all the different correct use and typical use statistics. I’m often questioned about efficacy, and I want to be able to answer people’s questions. If this also describes you, I recommend the following articles:

The Discovery of the Different Types of Cervical Mucus

Use-effectiveness and client satisfaction in six centers teaching the Billings Ovulation Method.

Field trial of billings ovulation method of natural family planning.

A prospective multicentre trial of the ovulation method of natural family planning

A Trial of the Ovulation Method of Family Planning In Tonga

A Response: In Defense of Truth in the Science of the Billings Ovulation Method

Misrepresentation of contraceptive effectiveness rates for fertility awareness methods of family planning

A Dive Into Resting Heart Rate and the Menstrual Cycle

I purchased a Fitbit device close to two years ago, and within months I noticed that my heart rate appeared to be correlating with the phases of my cycle. I’ve been charting resting heart rate since 2018, and I can say with confidence that it has lined up every cycle. This shouldn’t be too surprising because we already know that progesterone causes basal body temperature to rise, but heart rate does not exactly follow that pattern. Heart Rate also rises in response to high estrogen levels in the fertile window.

We have known about the possible connection between heart rate and the menstrual cycle for over a century, but in the last 50 years a few studies have taken a closer look.

Palmero (1991) studied 64 women for 3 consecutive months and created a PMS group versus a non-PMS group. They found that “in the premenstrual phase, PMS group showed significantly higher resting HR levels than NPMS group.”

Moran (2000) followed 26 women and found that “resting-heart rate was significantly higher in both ovulatory (P < 0.01) and luteal (P < 0.01) phases than in the menstrual and follicular phases.”

Shilaih (2017) followed 91 women and found that they “observed a significant increase in pulse rate (PR) during the fertile window compared to the menstrual phase (2.1 beat-per-minute, p < 0.01). Moreover, PR during the mid-luteal phase was also significantly elevated compared to the fertile window (1.8 beat-per-minute, p < 0.01), and the menstrual phase (3.8 beat-per-minute, p < 0.01).”

I want to highlight these last two studies in particular, because many of the other studies have an issue. Marco Altino explains why:

“The great majority of studies looking at HRV and the menstrual cycle collected one single data point during the follicular phase and one single data point during the luteal phase. I don’t have to tell you how little sense that makes, considering the high day to day variability in these parameters.”

This is an excerpt from his blog on heart rate variability in the menstrual cycle. Read the full blog here.

The 2017 study published in Nature by Shilaih, et al found that heart rate may rise up to 5 days before ovulation occurs. This means that heart rate could potentially be a used as a way to time intercourse for conception.

My results are so steady with resting heart rate that I dream of someone using it in a long-term study with other fertility signs. Wouldn’t it be cool if we could avoid pregnancy using heart rate too?

Below is an example of my results with resting heart rate. To convert my heart rate to fit in a fertility awareness app, I use a conversion. Essentially, one heart rate beat = .1 Farenheit change on my temperature scale. A heartbeat of 69 becomes 96.9, 70 becomes 97.0, 71 becomes 97.1 This preserves the original ratio, and it allows me to show the data with other fertility signs. For your own conversion, you may model this. If you have a lower heart beat rate, you can still convert, but you may need to do an additional equation.

My resting heart rate rose during the most fertile days of the cycle. Ovulation most likely occured on Cycle Day 15 or Cycle Day 16 on this chart. In addition, while I have not found evidence of this in the literature, I have observed that I tend to get a one day rise 3 to 4 days before the fertile window opens with cervical mucus. On this chart, that was Cycle Day 6.
A second example. Ovulation most likely occured on Cycle Day 14, 15 or 16. Heart rate rose on Cycle Day 14.

In conclusion, I believe that resting heart rate is a very unique sign to track, especially if you already use a wearable fitness tracker. I will note that a false heart rate rise can be caused by illness, alcohol or food close to bedtime, nightmares, and more! This is not dissimilar to what can obscure a temperature. I hope that in the future more studies are done so that we can see if heart rate can also be used for avoiding pregnancy purposes.

Selected Heart Rate Study Citations

Moran, V. H., Leathard, H. L., & Coley, J. (2000). Cardiovascular functioning during the menstrual cycle. Clinical physiology (Oxford, England)20(6), 496–504. https://doi.org/10.1046/j.1365-2281.2000.00285.x

Palmero, F., Choliz, M. Resting heart rate (HR) in women with and without premenstrual symptoms (PMS). J Behav Med 14, 125–139 (1991). https://doi.org/10.1007/BF00846175

Shilaih, M., Clerck, V., Falco, L. et al. Pulse Rate Measurement During Sleep Using Wearable Sensors, and its Correlation with the Menstrual Cycle Phases, A Prospective Observational Study. Sci Rep 7, 1294 (2017). https://doi.org/10.1038/s41598-017-01433-9

A Day in the Life of a Billings Ovulation Method User

Have you ever wanted to know what it is like to chart with the Billings Ovulation Method? This blog attempts to give an overview of what it is like for one individual to chart with the Billings Ovulation Method (BOM) over a single cycle. I go through each day of the cycle and explain my overall charting habits. All times are just approximate. I get personal and discuss some challenges I experience with natural family planning. BOM involves tracking sensation felt at the vulva along with the visible appearance of cervical mucus as a person goes about their day to day activities.

Day 1: Record heavy bleeding. Heavy bleeding feels wet. Done! Users are not allowed to use heavier days in the Billings method when avoiding pregnancy. This is a true day one of a cycle because it was preceded by a Billings peak day.

Day 2: Record heavy bleeding. Heavy bleeding feels wet. Done!

Day 3. Record medium bleeding. Medium bleeding feels wet. Done!

Day 4: Very light bleeding. It is now possible to observe my basic infertile pattern of dry.

8am: I feel dry and see a small amount of blood.

10am: I still feel dry.

8pm: I still feel dry. I see no mucus. Sex is allowed in the evening of this day. We use this day.

Day 5: Extremely light bleeding. Technically this day is not allowed for intercourse since I used the day before and Billings method rotates alternative evenings. We use this day anyway #rulebreaker

Day 6: I feel dry. I do not see anything. I record this day as “possibly fertile” since I broke a rule and used the day before. Every day after intercourse gets this white stamp in the pre-ovulatory time of the cycle.

Day 7: My basic infertile pattern of dry is still there! I notice nothing the entire day in the bathroom and my vulva sensation is dry. Sex is allowed in the evening. I consider my evening 8pm because I go to bed around 9pm on average. We use this day.

Day 8: I feel dry all day and see nothing. However, this day is not allowed since Billings alternates days. We skip this day.

Day 9: I feel dry all day and see nothing. However, we do not use this available day because we are both tired. It happens!

Day 10:

9am: I feel a bit moist. I don’t see anything when wiping in the bathroom.

11am: Still feel moist. I do not see anything in the bathroom.

2pm: Still feel moist. I do not see anything.

4pm: Still moist. Nothing seen.

4:45pm: Walking to my car from work. Still moist!

8pm: Overall observation for the day is moist. I record it. The fertile window has opened. This is known as the point of change.

Day 11:

7am: I feel moist as soon as I walk to the bathroom. I see very scant clear mucus on the tissue.

I do not see or feel anything for the rest of the day.

8pm: Overall observation for the day is “moist, clear”

Day 12:

7am: I feel moist, but see nothing.

10am: I feel moist, but see something white.

8pm: The feeling remains the rest of the day. I record “moist, white” for the day.

Day 13:

7am: I feel dry.

11am: I still feel dry.

1pm: I feel wet sensation when walking to my office. This is a change, so I keep that in mind.

I feel damp the rest of the day. I never see anything in the bathroom. I record “wet” as the most fertile sensation that day.

Day 14:

6:30am: I immediately feel moist.

9am: I see long clear strings when wiping in the bathroom.

11am: I have a wet sensation when walking around.

3pm: I walk around my work place. I still feel moist.

5pm: I see clear strings again.

8pm: I record “wet, clear strings” on my chart.

Day 15:

7am: I feel a gush as soon as I wake up. I do not see anything in the bathroom.

9am: I see scant, clear mucus on the tissue when wiping.

11am: I feel very wet walking around my work place.

1pm: I do not see anything on the tissue.

3pm: I do not see anything on the tissue.

5pm: I feel wet sensation while making dinner.

8pm: I record “wet, clear” as my observation for the day.

Day 16:

7am: I do not feel or see anything when waking up.

9am: I still do not feel or see anything.

12pm: I go for a 20 minute walk. When I get back, I feel slippery sensation. I go to the bathroom and see copious amounts of long, clear mucus.

8pm: I felt slippery the rest of the day. I record “slippery, long clear” on the chart.

Day 17:

6am: I feel dry when waking up.

8am: I don’t see anything or feel anything.

11am: I don’t see anything or feel anything.

8pm: The day was nothing felt, nothing seen all day. I record dry. This means yesterday was my peak day because it was a changing and developing pattern ending in slippery followed by an abrupt dry up to no longer wet or slippery.

Day 18 and Day 19:

I have the same experience as day 17. I pay attention all day and observe no mucus or sensation.

Day 20:

Ovulation is expected to be over and the cervical mucus plug has re-closed for the cycle. Sex is available any time for the rest of the cycle until day one of menstruation occurs. I can chart, but it is not necessary to wait until the evening and observations are less important as sex may interfere at any time.

Day 28: I record heavy bleeding and the rules restart.

Real Talk: Diffulties / Obstacles With Billings Not Seen on the Chart

These are things that I find can be difficul in my own personal experience. I know that people in really long cycles or with other irregularities may have different issues than me.

Challenge One: Alternative evenings only can be a struggle, and it seems even harder for me right before the fertile window opens due to my mood at this time of the cycle. This follicular phase is much longer for me than my luteal phase on average, and this means alternative evenings is the rule for most of my cycle. If someone has a partner with a conflicting schedule, this can especially be offputting. I think anyone who is going to practice this method should consider whether this is practical for their lifestyle.

Challenge Two: Expected abstinence in Billings can be hard, and I have fairly short fertile windows on average. I originally practiced sympto-thermal, and I switched to Billings when I realized that overall consecutive abstinence was much less overall (for my own cycle, Billings: 9 days, Sympto-Thermal: 14+ days). I tend to break some rules still, but this is much more suitable for my fertility intentions level than sympto-thermal.

Look out for my next blog on “A Day in the Life of a Marquette User.”

Disclaimer: Do not try to learn how to chart from this post. Everyone has their own unique cycle and this is just an example of charting with Billings in a regular cycle. Please reach out to me if you would like to learn this method with me as your guide. Alternatively, you can find a teacher here.

An Honest Review of Kegg

The kegg device draws a fertile window to give you the best days for conceiving a pregnancy based on the electrolyte levels present in the vagina. To use this device, someone would insert kegg into the vagina in the same two hour period of time during the day. kegg takes approximately two minutes to give the user a reading on the graph. As a bonus, it also gives you the opportunity to do kegel exercises while using it. Click here to read an article on the science behind kegg.

This product is an exciting development in the femtech field because it actually does read a real-time fertility sign. Cervical mucus is completely necessary for natural conception to occur. Without the presence of cervical mucus in the cervical crypts, sperm cannot to get to their destination to reach the egg. For this reason, anyone trying to conceive needs to track cervical mucus or use an alternative device such as Kegg (or a device that reads estrogen levels) in order to time intercourse for when they are most likely to conceive.

Here’s what Kegg looks like!
My kegg values compared to my Billings Ovulation Method cervical mucus observations. I believe that the kegg was highly correlated with my actual fertile window based on a traditional fertility awareness based method!

Who is Kegg right for?

It is important to know that kegg is not suitable for avoiding pregnancy. It is designed to find the most suitable days for conception. For those avoiding pregnancy, the fertile window has to be much longer than the window what the kegg gives. Until kegg has been studied for pregnancy avoidance, I cannot recommend it as an alternative to cervical mucus checks which must be made multiple times of day until the evening when someone is strictly avoiding pregnancy.

kegg may be right for someone who wants to conceive without needing to take a class or read a book on cervical mucus. In my experience, for the most part, it detected my most fertile days in a way that would likely lead to conception if used.

kegg may not be right for you if you have a very erratic schedule. Because it has to be used in the same two hours and cannot be used up to 8 hours after sex, this may make Kegg harder to use.

Click here to purchase your kegg!

Customer service with kegg has been excellent. The team is very reachable. If you would like to see more kegg charts and learn from fellow keggsters, you may join the kegg facebook group for conception or for those using it along with other fertility signs to avoid.

One Cycle Seven Ways: Experimenting with Marquette (Clearblue Monitor), Billings Method, Sympto-Thermal, Daysy, Kegg, DOT, and more!

Over the last several months, I have been testing multiple femtech products (such as Daysy Fertility Tracker, Kegg, DOT) and comparing them to charting methods like Marquette, Billings Ovulation Method, and Sympto-Thermal (NFPTA). These products and methods rely on different fertility signs such as basal body temperature, cervical mucus, urinary hormones, electrolyte levels, and calendar dates.

Disclaimer: Do not attempt to learn to chart using this post. My own experience may not reflect your unique cycles. My fertility intentions may not be your intentions.

Keep in mind that different methods may change safe days over time. The following data is only a snap shot of what fertility windows for avoiding pregnancy could look like. In particular, the Daysy thermometer only has 4 cycles of data on me.

Expected Consecutive Abstinence Over 3 Cycles

Cycle 52

  • Billings Ovulation Method: 15 (9 consecutive)
  • Marquette: 13
  • Sympto-thermal: 16
  • DOT: 12
  • Daysy: 15

Cycle 53

  • Billings Ovulation Method: 14 (8 consecutive)
  • Marquette: 13
  • Sympto-thermal: 13
  • DOT: 12
  • Daysy: 14

Cycle 54

  • Billings Ovulation Method: 16 (9 consecutive)
  • Marquette: 15
  • Sympto-thermal: 19
  • DOT: 12 (EXTREMELY RISKY)
  • Daysy: 15

From this data, you can see that sometimes the amount of expected abstinence does not differ from method to method, and sometimes it differs a whole lot! On my last cycle with DOT, it ended my avoidance window on the day after peak fertility occured. Fertility is still potentially high on the 3 days following this date.

Billings method almost always had the least consecutive abstinence because it relies on real-time fertility signs to open the window. However, because it rejects calculation rules and relies on one primary sign, only alternative evenings are ever allowed for pre-ovulatory sex. In addition, heavy days of menstruation are not allowed due to the possibility of early ovulation, and the bleeding obscuring the opening of the fertile window.

Other methods like Daysy, Sympto-thermal, DOT, and Marquette do allow pre-ovulatory consecutive sex, but most of that falls during menstruation for my cycle ranges (25 to 30 days).

Whatever method works best for someone is very dependent on their lifestyle and what someone is willing to diligently track.

The Same Chart Seven Ways

The highlighted days represent days to not use in order to avoid pregnancy with these methods.

My hearts are left on to show the fertile window and for authenticity. Do not use these charts to try to learn the rules of any method or to determine when sex is safe. You will see some broken rules based on my own personal intention level and on the fact that not all fertility signs will show the same window.

The Billings Ovulation Method draws the fertile window based on vulva sensation and cervical mucus. Any heavy bleeding is considered potentially fertile because it obscures readings and ovulation can always happen early. It requires alternating evenings for sex during the established basic infertile pattern.
This is the Marquette Method while using only urinary hormones and calculation rules. Fertile window opening determined by calculation rule based on last 6 cycles or first “H” reading on the Clearblue monitor. Clearblue measures estrogen and luteinizing hormone. My first window is also closed by a progesterone test in addition to meeting PPHLL rules.
This is the double-check sympto-thermal method per Natural Family Planning Teachers Association (NFPTA) rules. It opens the fertile window based on the shortest cycle in the last year minus 20. It closes the fertile window based on cervical mucus and basal body temperature.
This is a chart with the Daysy Fertility Tracker. This basal body thermometer learns your patterns over time and opens the fertile window based on past cycle data. The fertile window changes with time, and this is technically my 3rd Daysy cycle. Caution days and Red X days are for avoiding intercourse. Daysy does not allow the user to mark temperatures questionable, but I have marked two days questionable because I drank alcohol or had the heater on.
This example chart includes my cervical mucus notes for more context. DOT is a calendar based method that looks at the last 12 cycles of data. Only people in regular cycles can use DOT. Black moons are days available for intercourse based on the calendar method. In the next line, I also have included Kegg. Kegg predicts ovulation for trying to conceive purposes only, so I am including it as a bonus comparison. By reading the electrolyte levels in my cervical mucus, it determined that these 3 days were the most fertile days of the cycle. A full Kegg review is forthcoming in December 2020.
This is a resting heart rate chart. Resting heart rate has been shown to correlate with the menstrual cycle. I convert my heart rate like this: 69 = 96.9, 70 =97.0, 71 = 97.1, etc to be able to fit it onto the graph. You can see that it very closely followed my ovulatory pattern.
Here is my chart with all the data in one. It is so cool how different fertility signs draw the fertile window!

Unfortunately, my Mira Fertility sticks were flawed, so I had to remove that data from this experiment. In the future, I will do a comparison post also using this device. I am currently still testing the Kegg device, and a review with full Kegg charts is forthcoming in December. Kegg cannot be converted to display on the Read Your Body app, so I could only include the fertile days in this post.

Do you have any questions about all of these methods?

Consider coming to my free Instagram Live on femtech on November 28th. You can find me @chartyourfertility.

On December 12th, I’m offering a “pay what you can” introduction session that is minimum $5 to $30 USD on regular FABM methods and what the main differences are. Reach out to me if you would like to come.

Finally, a special shout to the Body Literacy Collective and the Read Your Body app for making this post possible by creating the most versatile charting app on the market!

What is Walking Sensation?: How to Check for Vulva Sensation While Going About Your Day

This article was originally published on fertilityawarenessmethodofbirthcontrol.com


While some fertility awareness based methods use wiping sensation, a large majority of sympto-thermal methods (as well as mucus-only methods such as the Billings Ovulation Method) use some variation of walking sensation.  Walking sensation is the feeling someone experiences at the vulva while going about their day to day activities. A good way to think about it is what it feels like to feel menstruation begin. Most people understand that this causes a wet feeling at the vulva without even needing to look to see the blood. Likewise, walking sensation can be felt at the vulva without needing to look for visible mucus. 

This feeling might feel like something is falling out of your vagina. It could feel moist, wet, sticky, lubricative, slippery, or similar terms. Some people describe trickles and bubbles. This sensation opens the fertile window even if no visible mucus is seen. In fact, it is common to have walking sensation open the fertile window before any mucus is seen. It is also common for slippery / lubricative / wet sensation to be set as peak day (depending on your method rules!). Again, this would count as a fertile day even without visible mucus being seen.

Walking sensation is a practice in mindfulness. It involves tuning into the nerves at the vulva as you go about your day. Notice how it feels when you walk around, exercise, or otherwise move throughout the day. Wearing tight pants or synthetic fabric underwears can make it harder to feel. If you are having trouble tracking walking sensation, consider wearing a skirt or dress for a full cycle.

Another common suggestion to help learn it is to “chart blind” for one full cycle (obviously you will need to refrain from unprotected sex if changing up your method!). Charting blind means charting your sensation without looking at your visible mucus. This forces you to rely on the feeling at the vulva. Note that the Billings Ovulation Method which relies on walking sensation as the primary sign has done small studies with blind women who were able to chart their patterns with it while never being able to see visible mucus. 

For those who haven’t tuned into these nerves before, I suggest meditation. Throughout the day, take the time to sit down (or walk around) and concentrate on your vulva.

If you are interested in learning more, reach out to an instructor. If you want to use it as a part of a mucus-only method, the Billings Ovulation Method focuses more on it than any other existing method. I personally teach this sensation in my Billings Ovulation Method class.

In Defense of Mucus-Only Methods (Specifically Billings Ovulation Method)

In the fertility awareness world, there are many misconceptions about mucus-only methods. While I cannot speak to mucus-only methods that I have not trained in, I can speak for what I have learned in training in the Billings Ovulation Method. There is so much history of the development of the method that I cannot touch on everything here. For those wanting to learn more, this document goes over some of the history of the method. Outside of that, WOOMB has many useful links.

First and foremost, the usual criticism leveled at mucus-only methods is that they have a low efficacy rating when compared to the sympto-thermal method. However, this is much more nuanced than it may appear at first glance. Let’s look at the most often quoted study for Billings.

This section of statistics is copied directly from a WOOMB International breakdown found here:

1976-78 an independent trial was conducted by the WHO, in five countries (India, the Philippines, New Zealand, Ireland and El Salvador).

This study had two phases:  
869 couples entered the three-month ‘teaching phase’,
725 couples continued in the 13-cycle ‘effectiveness phase’,
with a total of 10,215 cycles in the entire study.

The teaching phase showed that in the first cycle of charting, 93.1% of women were able to record an identifiable ovulatory mucus pattern denoting fertility, and that by the third cycle of charting, 97.1% of women had an excellent or good interpretation of the method.

The results for the entire study were:
2.2 pregnancies/ hwy    (per 100 woman years)  –  method-related pregnancy rate
22.3 pregnancies/hwy  (per 100 woman years)   –  total pregnancy rate

The total Pearl Index  – 22.3/hwy  comprised:
• Conscious departure from the rules of the method: 15.4/hwy.
• Inaccurate application of instructions: 3.9/hwy.
• Method failure: 2.2/hwy.
• Inadequate teaching: 0.3/hwy.
• Uncertain: 0.5/hwy.”

The first thing you should notice is that perfect use was 97.8%. This is pretty high. The second thing you should notice is that typical use includes people who knowingly broke the rules! All typical use always includes this. This statistic of 22.3% typical use failure is used to scare folks away from mucus only, especially when compared to one specific sympto-thermal trial by Sensiplan. However, the Thyma double check sympto-thermal had a 35% typical use rate in one trial. No method is impervious to bad typical use rates because this is dependent on how open someone is to pregnancy, as well as cultural factors. This is a flaw (depending on your perspective) of all FABM methods; someone can choose to achieve pregnancy because fertility is not suppressed.

The next thing to consider is that the older statistics of the Billings Method were based on a different peak rule, a very similar peak rule to which all sympto-thermal methods have adapted. As Billings continued to develop, the method was strengthened by over 850,000 hormonal assays completed by Dr. Brown which tested estrogen, follicule-stimulating hormone, progesterone, and luteinizing hormone. These tests were matched to Billings Ovulation Method charts. The method has been scientifically validated in over 10 total trials.

As the method was studied, the peak rule was changed to help women recognize patterns of fertility and infertility. They discovered when the specific peak rules were met, a changing and developing pattern of discharge and sensation <more specific rules apply to this>, ending at a slippery sensation felt at the vulva 《with walking sensation》and followed by an abrupt change to no longer slippery or wet, that a woman could detect a false mucus patch build up without the need for temperatures. Because of the science that Dr. Brown, Dr Evelyn and John Billings, and Dr. Odeblad verified through numerous studies, they were able to strengthen the mucus only method enough to no longer rely on temperatures without fear of double peaks. The most recent Billings study in China found a 100% perfect use rate and a 99.5% typical use rate when users were very strictly avoiding and highly motivated with the rules.

In short, the Billings Ovulation Method is very effective and for careful charters does not suffer the problem of false peaks. Again, I have barely scratched the surface of all the trials and science involved. I recommend researching Erik Odeblad and the pockets of shaw for more information.

So why do mucus-only methods get such a bad wrap? In the secular communities, I think there are a few main reasons.

1. The methods must be learned through a teacher. Learning these methods takes dedication and regular live (or online) meetings with a real person. Most folks don’t feel like making this effort or think they can’t afford it. Billings has a policy to never turn anyone away in need. Many do free services or payment plans when asked. There is also a charity associated with Billings that can sponsor Catholic couples to help them afford classes.

2. The next reason is that many sympto-thermal users have fundamental misunderstandings of what Billings is. As a certified sympto-thermal teacher and someone who has read about fifteen books on sympto-thermal, it is dissapointing how much of the original science of fertility and the cervix is left out of our materials. My mind was blown when I discovered how things really work when learning a mucus only. From the pockets of shaw to the functions of the cervical crypts, there is so much to learn that is not included in Taking Charge of Your Fertility. This does a great disservice to sympto-thermal charters.

3. Due to these misunderstandings, they think the method cannot be used by those with irregular cycles. They also may think that a non dry basic infertile pattern is not possible due to a misunderstanding of the science of the cervical plug and the effect of estrogen in the vagina.

Potential Cons of Mucus Only:

I do not say any of this to say that the Billings Method is right for everyone. It takes dedication and a willingness to follow the rules if strictly avoiding pregnancy. In addition, there are a few cons to mucus only.

1. A yeast infection or bacterial vaginosis would obscure observations and cause abstinence. However, arguably even a sympto-thermal user would need to abstain when they have an infection.

2. Women who are careless with mucus observations may end up with an unintended pregnancy. If you don’t want to track mucus carefully, this is not the right method for you. If you can’t follow the rules to safely have intercourse, such as evenings only during basic infertile pattern on alternate evenings in the pre-ovulatory time of the cycle, this method may be too restrictive for you.

3. A weak mucus patch that does not fulfill the stringent peak rules may cause more abstinence without a temperature shift to confirm. However, this often signals a potential health issue and should be investigated.

4. Mucus only methods do encourage abstinence when avoiding pregnancy. However, most sympto-thermals do the same. Anyone who is okay with an elevated risk due to barriers or alternative protected sex can always do what they want to do but should be prepared to face the consequences if a barrier method fails.

Conclusion:

Mucus only methods can be highly effective choices for avoiding pregnancy. Recent trials of Billings consistently show 99% or better with perfect use. In some cases, they may reduce abstinence because they allow women to identify false mucus build ups that do not lead to ovulation and non-dry basic infertile patterns. For women who want to eliminate barrier method usage, they offer a way to identify fertility in real time when in irregular cycles due to PCOS, postpartum, or perimenopause. This eliminates much of the extended abstinence or barrier method usage that sympto-thermal users may experience.