Why Natural Cycles doesn't work - and why Fertility Awareness does
For the last couple of weeks the fertility tracking app Natural Cycles has been in the lime light, with claims that many women using the app for contraception has instead ended up pregnant.
Natural Cycles is an application where women every day measure and chart their body temperature. Based on data from previous cycle the app will then calculate the likelihood of the woman becoming pregnant on that specific day.
Upon a first look, this might sound like a Fertility Awareness method. But in fact, it is very different. In this blog I will try to explain why.
It's all about the mucus
The problem with methods based solely on tracking one's temperature, is that body temperature can only confirm that ovulation has happened, after it has already happened. Meanwhile, a healthy woman is fertile for several days before ovulation. That is, she is fertile on days when she secrete cervical mucus. Cervical mucus is a magical substance secreted by the cervix (the opening to the uterus, in the back of the vagina), which is needed for sperm to survive and fertilize an egg. In it, sperm can survive up to 5 days and await ovulation – without it, sperm will die within minutes. Cervical mucus travels down from the cervix to the vaginal opening, where a woman can learn to find and recognize it. Cervical mucus is the main sign of fertility we look for when using the symto-thermal method of Fertility Awareness for birth control (or for any other purpose). We combine cervical mucus observations with taking our temperature – but we are aware that the temperature shift occurring at ovulation only can confirm that ovulation has happened – not predict it.
If you were now talking to the the developers of Natural Cycles, this is when they would tell you that they use a cutting-edge algorithm to calculate the days before ovulation when a woman is fertile – so that mucus observations is obsolete. This is where I take on my nerdiest Fertility Awareness educator glasses and tell them: algorithms will never work. Why? Because the female body is not a machine. It is a dynamic process that changes throughout the woman's life.
The dynamic cycle
You might have been charting your cycles for several years, and always had clockwork regular cycles. In this case, Natural Cycles and other fertility calculations might very well have worked out perfectly for you. But even after all those year, something can happen that makes your cycles suddenly change their rhythm. Maybe you are going through a really rough break-up, doing a long journey, or involving yourself in strenuous exercise before your first marathon. All of these are examples of events that can make the most regular cycle get out of hand for a while, since the menstrual cycle is stress sensitive, constantly adjusting to our present life situations. Other causes to why ovulation might suddenly occur earlier or later in the cycle are entering perimenopause, experiencing health improvements, or going through the natural regulation of the cycle happening in the year/s following use of hormonal contraception.
To put it shortly: even if you have clockwork regular cycles, it is very likely that your rhythm one day will change. And when it does, a calculated algorithm will fail.
Since the sympto-thermal method of Fertility Awareness is based on day-to-day observations of tangible physiological signs, and not on calculations, it will flow with you through all these changes. A Fertility Awareness method using direct observations of fertile signs can be used in all periods of life, regardless of how irregular your cycle might be (although, in the case of irregular cycles, guidance by a certified educator is strongly recommended).
But there are other reasons as well to choosing a Fertility Awareness method instead of a calculation app. Fertility Awareness gives you profound empowerment and knowledge about yourself. Through monitoring our physical signs of fertility as a daily practice, we come closer to ourselves in a unique way. Thus Fertility Awareness doesn't only give us a highly reliable tool for birth control and reproductive health management, but it gives us back the power over our bodies and ourselves.