Goal: track ovulation
The time window for getting pregnant is short, lasting just six days per cycle. What’s more, the probability that you’ll fall pregnant isn’t the same on all days. How can you tell the best time to conceive?
If you bet on pregnancies, you wouldn’t stand a very good chance of winning, because studies indicate that the statistical probability of falling pregnant is between 20 to 30 percent per cycle – and only on three of the six fertile days (i.e. the three days that are closest to ovulation). Four days before, the chances of conceiving are only 10 to 12 percent, while five or six days prior to ovulation the probability falls to between 0 and 5 percent. This brings us to the critical question: when do I ovulate?
How fertility apps work
Fertility apps would appear to be a simple way of calculating your ovulation cycle and fertile days. However, they're based on a standard cycle, according to which ovulation starts 14 days before your next period. The problem is that 70% of women don’t have standard ovulation cycles (source: Ava). As you only have three up to a maximum of six fertile days per cycle, it can be critical if you miscalculate ovulation by just two days.
Another way to determine the moment of ovulation is to study the development of your hormones. Five days before ovulation, your oestrogen levels increase. This can be determined either by observing the cervical mucus – the discharge is stretchier, more transparent and thinner prior to ovulation – or by using a commercially available ovulation test. These tests work along the same lines as pregnancy tests: you either urinate on a test strip directly or dip it in a cup of urine. The results are based on the levels of oestrogen and luteinising hormone (LH) which increases around 24 hours prior to ovulation. The disadvantage of ovulation tests is that if your hormone levels are not high enough, they show the increase too late or not at all. And frequent visits to the toilet with test strips can be annoying. Another way to determine the point of ovulation is to observe the levels of progesterone, which increase after ovulation. This is signalled by a higher body temperature. However, as soon as you register an increase in temperature, ovulation is over. In fact, taking your temperature is another way of determining your fertility window. After ovulation your body temperature rises by round 0.5 degrees. If you observe your body temperature over a longer period, you can determine the days on which you are fertile. At least in theory. This method is very imprecise and highly prone to error.
Source: Studies: Wilcox, Human Reproduction, Colombo, Demographic Research, Ava and Swissmom
The Ava ovulation tracker offers a simpler and more reliable way of determining ovulation than using fertility apps, measuring your body temperature daily or observing your cervical mucus. Ava is a bracelet with built-in sensors that has been clinically tested at Zurich University Hospital. It determines around five fertile days per cycle, thus doubling your chances of getting pregnant. Having sex every other day during the fertile window is proven to increase a couple’s chances of conceiving. Compared to unplanned sex once a week.*
Find out more about Ava here.
*Study: Allen J. Wilcox Clarice R. Weinberg Donna D. Baird. New England Journal of Medicine, December 7, 1995.