How to calculate your ovulation
Did you know? The number of eggs you have is already determined at birth. Because hundreds of thousands of immature eggs (“oocytes”) are already dormant in your ovaries at birth. Each one of them can theoretically become a little human being. But in practice, of course, this does not happen: On average, “only” 500 of these eggs pop in a woman’s lifetime. The body reabsorbs all the others over time until there are none left and menopause sets in.
What happens during ovulation and my fertile days?
Very simply - roughly once a month a follicle ripens and releases an egg, usually about 10 to 16 days before your period starts. The egg develops in the ovaries and is released into the fallopian tube where it continues on its journey towards the womb. The follicle in which the egg matured transforms into the “corpus luteum”, which produces progesterone, needed to build up the lining of the womb where the fertilized egg can then nest. If the egg is not fertilized it dies and menstruation begins.
This process is hormonally controlled and thus takes place in almost every cycle. Some women can feel the changes during this time very clearly. You may also be familiar with “mittelschmerz”, a pressing or stinging sensation in the abdomen during ovulation. Breast pain, clear cervical mucus, or increased libido may also indicate ovulation. However, these are only indications and not sure signs of ovulation.
Is there a generally valid formula to calculate my ovulation?
No, unfortunately, there is not, we must disappoint you. As already mentioned, in a regular cycle of 28 days, ovulation normally takes place between the 10th and 16th day before the next menstrual period. So, ovulation on day 14 of your cycle is the approximate value. However, since every woman is different and the length of her cycle varies greatly, it is not possible to make a generally valid statement here. However, there are various methods that help to calculate the exact day of ovulation, and we have taken a closer look at 5 of them and tested their reliability.
1. The calendar method: determine ovulation by days
The method: The calendar method, also called the “Knaus-Ogino method” after its developers, is probably one of the best-known means of determining ovulation. It is also called “counting days”: you start from your normal cycle length and can thus predict the period of ovulation (around the 14th day of the cycle) and also the next menstrual period.
Advantages: Basically, the method is very uncomplicated and, of course, cheap: apart from a pen and a calendar, you don’t really need anything.
The disadvantages: Counting days is very inaccurate. Only very few women have a “picture perfect cycle” or ovulation always on cycle day 14, so the calendar method can at best offer some clues or serve as a menstrual calendar. In fact, the calendar method is not recommended for women who do not want to become pregnant. Also, for women who want to have children, there are much better methods to determine the fertile time.
CONCLUSIONS:
Effort: low
Costs: low
Accuracy: rather poor
2. Ovulation tests: measure hormone concentration
The method: Ovulation tests work in a similar way to pregnancy tests. However, the rods do not measure the pregnancy hormone beta-HCG in your urine, but the luteinizing hormone (LH), which triggers ovulation. The closer you get to ovulation, the stronger the streak on the test.
The advantages: You don’t need any equipment other than the sticks. You can usually buy ovulation tests cheaply in large stock packs - so you can easily cover several cycles.
The disadvantages: The tests cannot accurately calculate the day of ovulation. Unfortunately, LH tests are not always completely accurate and reliable, different factors can influence the result. For example, the LH concentration in morning urine is higher than the rest of the day. On the other hand, the hormone concentration decreases when you drink a lot. Scientists have found that some women have several LH surges in one cycle. This means you can’t always pinpoint ovulation to a single surge. Check out this blog post for more info on LH testing.
CONCLUSIONS:
Effort: low
Cost: medium
Accuracy: rather poor
3. Natural family planning: monitor temperature and cervical mucus
The method: A sure sign to determine ovulation is the rise of your basal body temperature (waking temperature). On average, the temperature rises by about 0.2°C- 0.5°C at ovulation and only drops again when your period starts. Natural family planning” (also called the “symptothermal method”) makes use of these and other changes in the body. You will need an analog thermometer or a digital one with two decimal places, as well as a way to record your temperature curve.
The advantages: By keeping a temperature chart and observing the consistency of your cervical mucus before ovulation, you can narrow down the timing of your ovulation. On the one hand, this method is very accurate, and on the other hand, it is suitable for both contraception and childbearing.
The disadvantages: The symptothermal method has a comprehensive set of rules and is very time-consuming. Getting up at night, alcohol or restless sleep can already disturb your basal body temperature, so that you cannot evaluate your curve. Also, not all of us have the necessary consistency to constantly think about measuring.
CONCLUSIONS:
Effort: very high
Cost: low
Accuracy: good
4. Cycle apps: Digital ovulation calculator
The method: Digital cycle calculators are more or less the smartphone version of the calendar method. In any case, the range of apps available in the app stores is huge. Each app works according to different parameters. Basically, you enter the start of your last period and get a prediction for your fertile time.
The advantages: As long as you have your smartphone with you, you always have an overview of your cycle. Most apps allow you to personalize and add to your records. That way, you’ll gradually learn more about your cycle.
The disadvantages: Most apps evaluate the data according to averages and algorithms that may not apply to every woman. So, they can serve you as a menstrual calendar and provide clues about when you ovulate, but hardly any can determine it exactly, because individual factors, such as the temperature rise or cervical mucus before ovulation, are not taken into account.
CONCLUSIONS:
Effort: low
Cost: low
Accuracy: rather poor
5. femSense, the best of both worlds: Discreetly and safely determine ovulation
The method: femSense measures the postovulatory rise of your basal body temperature using a highly sensitive sensor, similar to Natural Family Planning. The system determines the exact time when your ovulation occurred. You attach the sensor to your skin with an adhesive patch for a maximum of 7 days per month and read it twice a day with your smartphone using NFC technology (which you already know from cashless payments with your EC card) so that the algorithm can always work with the current values.
The advantages: femSense combines the accuracy of temperature measurement with the convenience of a digital menstrual calendar. You have no hassle, as the femSense patch does the measuring for you. You just have to remember to read the patch and renew it every cycle - or let the app remind you.
The read data then allows the free femSense app to tell you exactly when your fertile days start or when ovulation occurs. Additionally, you can track your cycle in the app (even without a patch), enter your own observations as well as symptoms, and learn more about yourself and your body.
The disadvantages: The patches cost you something, of course. But in return, you get a safe, discreet, and reliable means to determine your ovulation - whether for Natural Cycle Control or to fulfill your desire to have children one day.
CONCLUSIONS:
Effort: low
Cost: medium
Accuracy: very good
Sources:
https://www.netdoktor.at/anatomie/eierstoecke-7194 https://www.echtemamas.de/wie-viele-eizellen-produziert-eine-frau-in-ihrem-leben https://www.minimed.at/medizinische-themen/frauengesundheit/eisprung/ https://www.netdoktor.de/kinderwunsch/ovulationstest/
