Many of us are drawn to each new shiny gadget or tool to come along, and this is even more pronounced in today’s tech-heavy culture. This is true in the realm of fertility awareness as well. Just look at some of the numbers: An estimated 14-15 million women are using fertility tracking apps (most of them simple period trackers), and it is estimated that $1.3 billion will be invested in 2020 in new femtech startups.

But before purchasing a device or app to use with your fertility awareness based method (FABM), it’s important to consider your goal.

Goal 1: I want to track my periods so I can anticipate when the next one will start. Most of the simple period trackers can be reasonably accurate, but it’s good to understand that some variability in cycle length is very normal. We’ve all been told that a 28-day cycle is “normal,” but did you know that only 12% of cycles are 28 days in length? It’s normal to have some slight variation in length from cycle to cycle. More accuracy on knowing when the next period will start can be found using a fertility tracker based on an NFP method. These can identify the luteal phase (the time from ovulation to the start of the next period) which provides more precision when calculating the start of the next cycle.

Goal 2: I’m trying to achieve pregnancy. For this, the timing of marital intimacy on the most fertile days of your cycle is important. Just learning a FABM that relies on the daily observation of fertility signs will be the most cost-effective means of knowing your most fertile time. Many devices claim to pinpoint the day of ovulation, but very few have solid clinical data to support their claim. The gold standard for detecting ovulation is ultrasound, but that is not feasible in practice. Several studies have shown that the best “user-friendly” means that correlates with ultrasound detection of ovulation is the knowing the day of Peak fertile mucus. Urinary LH (luteinizing hormone) test strips are also very good. Also, don’t be fooled by thinking you need to know the moment of ovulation in order to conceive; sperm can survive 3-5 days in the presence of fertile cervical mucus; the egg can live up to 24 hours. The gold standard for detecting ovulation is ultrasound and several studies have shown that the best “user-friendly correlate with ultrasound ovulation is the day of Peak (most fertile) type mucus. Urinary LH ( luteinizing hormone) test strips are also very good.

Goal 3: I’m trying to postpone pregnancy. In this scenario, using a FABM that employs daily observations and has published data on unintended pregnancy rates is the gold standard. Beware that many so-called fertility tracking apps are in fact no more than menstrual cycle trackers that rely on calendar rhythm. Others employ less common daily observations that have not been scientifically shown to be effective. The critical feature of a good method will define the beginning and the end of the fertile window regardless of cycle length.

Goal 4: I’m tracking for health reasons. This is why many women learn a FABM — they give insight and information on overall period length, menstrual patterns, luteal phase length and other characteristics of your cycle. Simple period trackers won’t help much here. Methods and devices that provide data on hormone levels — particularly estrogen, luteinizing hormone and progesterone — can be extremely useful if you have underlying disease.

With so much to consider, we are excited to be able to provide some guidance on the emerging technologies through our Live the Love initiatives. Our page at livethelove.org/femtech offers reviews and analysis of some of the most popular forms of femtech, our effort to help users discern which of these tools would be helpful to them and which may be just a waste of time and money.