Blog of the Society for Menstrual Cycle Research

Adventures in Building a Fertility Awareness Charting App

June 20th, 2012 by Kati Bicknell

I’m obsessed with fertility charting, and in my search for a Fertility Awareness app that met my needs, my husband and I created one.  The most important thing to us are our users, and their feedback is gold. We learned the hard way that women want to chart on their phones, not their computers. We want to avoid the mistake of thinking “we know best” again.  So what our customers say to us is taken very seriously. But sometimes they ask for things that we don’t want to give them!

I received a question from one of the women who downloaded our app, asking me if there was a way to enter temperatures measured to the 1/100th of a degree, (like 97.34).  She didn’t want to round to the tenth of a degree (97.3)  and risk throwing off her chart.  We thought we understood her concern.  If you’re taking your temperature every morning, you want that exact temperature to go in your chart! Rounding seems like it might throw off the chart. Right?

Well that depends on if you’re measuring in Fahrenheit or Celsius.  If you’re measuring in Celsius you must measure to .05 of a degree to catch the temperature shift.  In Fahrenheit you only need to measure to tenth (0.1) of a degree. Measuring to the hundredth (.01) of a degree is too small of an increment to make any important difference on your chart.

When charting basal body temperature (BBT), the bi-phasic temperature pattern over the course of your cycle tells you if you’re ovulating, when you’re ovulating, and the length and health of your luteal phase.  Post-ovulatory temperatures are usually around 0.3 degrees Fahrenheit higher than the preovulatory temps.  0.3 is larger than 0.01 by a factor of 30. This means that measuring to hundredths of a degree is not necessary to catch the temperature shift.

Typical Rounding Scenario

This graph shows a typical bi-phasic temperature pattern, clearly confirming ovulation.  The red line was graphed using temperatures that were accurate to the 1/100th of a degree.  The blue line is graphed using those same temperatures rounded to the 1/10th of a degree.  As you can see, the difference between the two lines is not enough to obscure a temperature shift on a chart.

We had a moment of deliberation… do we tell our user to just get a different thermometer?  Do we tell her to round her temperatures?  That didn’t seem like great customer service.

We realized that the solution is not to simply tell this woman why what she was concerned with didn’t matter.  From her perspective, rounding temperatures is a pain in the ass and she doesn’t want to do it!  THAT “pain in the ass” factor is the problem that we have to solve.  So, with this realization we decided to add the ability to chart in hundredths to our development plan.

Even though measuring to this accuracy isn’t necessary, if adding the second decimal place on our data screen makes it easier for women to get their data into the chart, we’ll do it!  We want all women to have access to the yummy benefits that are to be had from charting one’s cycle, and we are committed to removing the barriers to that, however it must be done.


6 responses to “Adventures in Building a Fertility Awareness Charting App”

  1. Kate Merritt says:

    Hi Kati- great to hear about your app. I downloaded it yesterday and I fell in love at first entry. Your attention to the user experience is obvious and it is by far the most intuitive and beautiful charting app I’ve tried. I’m new to charting and was misinformed and thought that the 1/100th degree was necessary. So thank you for informing me of my own misunderstanding, but more importantly of your dedication to listen to your users.

    That said, why do you market the app as only “The Intelligent and Organized way to Get Pregnant” when your knowledge of the effectiveness of FAM for contraception is clear through your blogging? Body literacy is important for all and has many uses. It seems counterintuitive to the educational aims of Kindara to present it as only a means to conceive when it is in fact- much more.

  2. Hi Kate,

    Thank you so much for your comment! I am beyond thrilled about your reaction to our app! It’s true, we have devoted a lot of attention to make Kindara beautiful and intuitive, a charting app that women will WANT to use. So it’s great to hear that that comes across.

    Like you, I see a huge potential for FAM to change the way women manage their fertility, whether that is to get pregnant, not get pregnant, or to know their bodies better.

    I myself have used FAM to avoid pregnancy for 3 years. When I started charting there was no app that met my needs. So that’s why we created Kindara. My husband and I have been working on Kindara full-time for the past 2 years, and we were finding that the market for FAM for birth control and body literacy is just not large enough yet for us to make a sustainable business out of it.

    So we are focusing on the pregnancy angle to establish ourselves as a trusted company in fertility. When more people know about FAM I think that it will become quite popular for it’s other applications. Our vision for Kindara is to give women the best fertility charting tools, and information, so they can chart their fertility for whatever purpose they desire. :)

  3. Kate Merritt says:

    I understand where you are coming from. I believe Toni Weschler said that her book “Taking Charge of your Fertility” is most often purchased by women trying to conceive, however the information about the other benefits of charting are fully disclosed.

    It seems like noting all of the benefits in addition to achieving conception wouldn’t cause profits to dwindle. It might cause women to tell their friends and continue to use the app after their pregnancy and throughout the remainder of the fertile years. However, not mentioning the many benefits of fertility awareness could perpetuate the myth that FAM isn’t a reliable form of birth control when used correctly. Just my two cents.

    Thank you for your hard work, it is appreciated! I believe that with good design and thorough education, body literacy will become popular. Kindara is definitely a huge step towards that. My interests lie in alternatives to hormonal contraception ( If you are keen I’d love to talk with you more about your research.

  4. Hi Kate,

    You make good points. I’ll take everything you said into consideration, as I certainly don’t want to alienate women who would use this for birth control and/or body literacy.

    We’ve worked a lot on messaging, and we still feel like we haven’t solved it. In my mind it’s really one goal, helping women understand their bodies so they can meet their reproductive goals (whatever they may be) and feel sexy, sane and savvy about their bodies. But we have not come up with a way to say this that resonates with the masses yet. I’d be interested to hear your thoughts on this, and if you have any ideas for us.

    I’m very interested in your project, Taking Control. I’d love to talk to you about it.

  5. Jerry Pecor says:

    Hey Katie, I think adding the extra info on the related benefits of fertility tracking, such as FAM, can open and broaden perspectives on the value of knowing your body. It can jump start a young persons interest into pursuing this knowledge and deciding to take control of their own health.

    Keep up the great work…..

  6. Hi Jerry,

    Thanks for commenting! I agree with you. :) We are still working on our messaging, and I’ll certainly take into account what you said. It’s great to have so many people understand and support our big vision! Now the trick is figuring out how to make a viable business out of that big vision. I hope people are ready for it! :) So exciting. Thank you for you support. It means a lot to us.

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