Contraception by following your own cycle

By Francine van Broekhoven

Did you know that you are only fertile for 18-24 hours per monthly cycle? And that sperm cells can survive in the female body for only five days, leading up to ovulation? So you can only get pregnant by having sex a few days before or the day of your ovulation.

Contraception is often a headache (sometimes literally) for women. Which method best suits your lifestyle and what makes you feel most comfortable? It is a matter of trying and getting advice. The standard in the Netherlands has been hormonal contraception for years. But did you know that there is also a natural way of contraception?

It is a biological fact that women ovulate once per cycle. In very exceptional cases, there will be 2 ovulations, but they always happen within 24 hours. After ovulation, the egg can be fertilized for up to 18 hours and after intercourse sperm remain active and fertile for up to 120 hours (5 days). The cycle is different for every woman, but on average it lasts 28 days and based on the basal temperature you can know which phase of your cycle you are in and therefore whether you are fertile or not. Ovulation takes place under hormones that lower the temperature. So the day of your ovulation you always have a measurably lower temperature. After ovulation, the hormone progesterone is released, causing the temperature to rise again. Your temperature will then remain high and as soon as your temperature drops again, you will immediately have your period. The figure below shows an average cycle in phases.

The big objection to hormonal contraception is that it can disrupt normal processes in the body. Disrupting the cycle often brings side effects. Known side effects of regular contraception with hormones include depression, increased risk of breast cancer, decreased libido, nausea and headaches. These chemical hormones can confuse the body in such a way that it can take months to years to get back to your normal cycle after stopping.

The “fatigue” with regard to these side effects and the refusal to burden the body with chemicals is driving an increasing demand for natural alternatives. Most of these natural methods use the temperature method. By measuring your basal body temperature (usually right after the alarm clock in the morning) you can recognize patterns in the cycle and calculate whether you are fertile or not. In the image above you can clearly read the temperature trend in relation to fertility.

Measuring and calculating all this yourself is very difficult and is very prone to error. That is why the Cycle computer was developed.
This is a cycle computer with a fixed measuring instrument that measures your temperature and then compares your data by a smart algorithm with 4 million cycles of tens of thousands of other women. This results in a green light (infertile, go ahead) or a red light (fertile, no unprotected sex). In addition, the Cycle computer gives you insight into your own hormone balance. Women using Cycle computer say they are relieved to finally understand their cycle again and feel much more in touch with their own body. For example, they know exactly when to expect their next period.

Now this probably sounds too good to be true and you have your doubts about its reliability. These doubts are unjustified. The Cycle computer has a theoretical reliability equal to the pill (99.3%). This means that with perfect use, about 7 in 1000 women will become pregnant. It is important to consider practical reliability in addition to theoretical reliability. This figure takes into account usage errors. The Cycle computer is 96.4% reliable in practice. This practical reliability is a figure that many women do not know about. The table below shows the theoretical reliability versus the practical reliability of different contraceptive methods.

MethodTheoretical reliabilityPractical reliability
Cycle computer99.3%96.4%
Natural Cycles99.3%93.2%

Natural Cycles is natural contraception that works with a separate thermometer and an application on a smartphone.

Source: World Health Organization (WHO), Dutch College of General Practitioners (NHG, based on Trussell, 2011).

Are you exploring the area of contraception or are you thinking about switching to the Cycle Comp after reading this article? Google has all the information.