In years gone by, women would rely on the calendar on the wall to work out when their next menstrual cycle might occur. They would look to physical signs to tell them when they might be ovulating, and therefore when they’d be most likely to conceive.
More recently, we’ve seen the proliferation of mobile phone applications helping women track their current cycle, predict their next cycle, and work out when the best time is to try for a baby.
The personalization and convenience of apps make them empowering and attractive. But they require some caution in their use.
The Menstrual Cycle
A woman’s menstrual cycle consists of three phases: menstrual bleeding, the follicular phase (when an egg-containing follicle is growing) and the luteal phase (the two weeks after ovulation prior to the next period).It’s traditionally been thought that the follicular phase varies in length between women, whereas the luteal phase is relatively constant between women—generally around 14 days. All phases together are thought to add up to a cycle lasting about 28 days.
Physical changes during ovulation include altered vaginal secretions and a subtle drop and then rise in basal body temperature.
How the Apps Work
When a woman logs the beginning of her menstrual cycle, fertility apps attempt to predict, using inbuilt algorithms, when ovulation might occur. The app then recommends the timing of intercourse accordingly to optimize the user’s chance of becoming pregnant.Calendar-based apps rely entirely on menstrual cycle length and an assumption that ovulation occurs 14 days before the next period.
Many of the more sophisticated apps collect data on basal body temperature, while some also call for a woman to examine her cervical mucus secretions, or include results from at-home ovulation test kits.
Are They Effective?
Australian researchers recently looked at 36 fertility apps most commonly downloaded by Australian women. The research, yet to be published, indicated that fewer than half of the apps (42.7 percent) predicted the correct ovulation date.For apps collecting temperature data, the prediction of highly fertile days was also commonly missed due to the use of data from previous rather than current cycles.
It’s likely the apps that request more information will have better accuracy. But their effectiveness also relies on the user entering information correctly and consistently.
An Algorithm Can’t Capture All Factors That Affect Fertility
Although we need more research in this area, the evidence so far suggests if you’re trying to have a baby, you shouldn’t rely too heavily on an app—particularly if you’re finding it hard to conceive.Various factors such as diet, exercise, body weight, and ethnicity can play a role in a woman’s menstrual cycle and a couple’s chance of conceiving. While many apps allow users to input this information, changes such as an increase or decrease in body weight, or times of high stress, which may lead to irregular menstrual cycles, aren’t incorporated into the algorithms that predict when a woman will be most fertile.
This may contribute to a delay in conception and lead to distress, particularly if a couple has already been trying to conceive for many months.
Fertility apps can be beneficial for documenting monthly cycles and help women identify when their cycles may be irregular. When this is the case, this may be a sign of other reproductive health issues, and women should see a doctor.
In women who have reproductive health issues such as polycystic ovary syndrome or endometriosis, the ability to become pregnant is already reduced. An app estimating ovulation or suggesting the most fertile period in these women may, therefore, be limited in its effectiveness.