Why I Don’t Recommend Natural Cycles (And What I Use Instead)

When I first came off hormonal birth control in 2017, I knew I didn’t want to use hormones again — but I also wasn’t ready to get pregnant. Like so many women, I downloaded the Natural Cycles app, thinking I’d finally found a hormone-free, science-backed option.

Spoiler: it didn’t end well. Just a few months later, I found myself staring at two pink lines. And while I wouldn’t change that outcome (my babies are my world 💕), it was a wake-up call that taught me just how misleading these so-called ‘fertility tracking’ apps can be when you’re relying on them as birth control.

Here’s why I don’t recommend Natural Cycles.

1. The missing piece: Cervical mucus

Cervical mucus is the body’s earliest and most reliable sign of approaching ovulation and how you identify your fertile window has opened. It’s your “early warning system” before you ovulate, which gives you the insight you need to successfully avoid pregnancy, given that sperm can survive 3-5 days in optimal CM. 

Natural Cycles doesn’t use cervical mucus at all. Instead, it relies on predictions and past cycle data to tell you when you’re “safe” in the early part of your cycle. But cycles can and do vary. Early ovulation, postpartum changes, perimenopause, and conditions like PCOS along with normal variations, can all make you ovulate outside of predicted patterns. Without mucus tracking to actually open the fertile window, you’re left exposed to the risk of pregnancy.

Even Natural Cycles acknowledges that mucus tracking “can be difficult for users to learn on their own, as all bodies are different,” and they suggest learning it with the help of a professional like a doctor, nurse, or family planning counselor. That’s true for many women — working with an instructor does make learning faster and more confident. But many women are perfectly capable of observing and interpreting their cervical mucus on their own using resources like Taking Charge of Your Fertility (TCOYF) or methods like Sensiplan.

If tracking mucus requires guidance, how can an app that ignores it truly provide reliable protection?

2. It uses temperature only (LH optional)

This is the biggest red flag for me. Natural Cycles relies on temperature alone to work out your fertile and infertile days. But here’s the problem: your temperature confirms ovulation only after it’s happened. And if you’re using a method for birth control, you need to know before you ovulate — not just afterward.

3. The ‘safe’ green days aren’t always safe

One of the scariest features of Natural Cycles is how often it hands out green (aka “safe”) days in the early part of the cycle, before ovulation has even happened. It’s often far beyond what any established method would give — and even from your very first cycle.

Without knowing if ovulation occurred in the previous cycle, or whether your bleed is a true period or a breakthrough bleed, these early green days can be risky.

It’s also common to see users online report the app switching green days back to red too — examples of why predictions based on past cycle data, especially early in the cycle, are risky.

Even Natural Cycles itself admits a typical use failure rate of around 7% — a far cry from the confidence most women think they’re buying into.

4. It’s not true fertility awareness

Natural Cycles is a temperature-based algorithm, not a comprehensive Fertility Awareness-Based Method (FABM).

It doesn’t teach you to understand your body. It teaches you to outsource your fertility to an app. That might be fine for some, but if you’re serious about avoiding pregnancy — or genuinely want to learn your cycle — you deserve better. Evidence-based education > app marketing every time.

5. Natural Cycles was my gateway into real fertility awareness

Here’s the thing: I don’t regret trying the app at all — because it opened the door to real fertility awareness. It got me thinking about my cycle, my ovulation, and how my body works.

But eventually I discovered that established Fertility Awareness-Based Methods (FABMs) existed — methods that teach you to read your body, track cervical mucus, and reliably identify fertile days. That’s when I realized there’s a big difference between an algorithm telling you if you're safe and a method that teaches you the science of your own body.

So what’s the alternative?

If you want hormone-free, effective birth control (or a reliable way to conceive), a double-check method like Sensiplan is gold-standard. It combines cervical mucus and temperature observations, so you’re not relying on an algorithm or hoping predictions line up with your biology.

And the best part? Once you learn it, the knowledge is yours forever. No subscription, no green-day roulette — just real confidence in understanding your body.

Final thoughts

If you’re considering Natural Cycles, I get it — I’ve been there. But from my own experience, teaching countless women, and seeing women post online about their own journeys, I can say with certainty: an algorithm can’t replace body literacy.

Learning a real Fertility Awareness Method gives you clarity, confidence, and choices — without the guesswork of an app that doesn’t actually teach you how your body works or the nuances that come with charting.

If you’re ready to ditch the confusion and finally feel confident with your cycle, this is exactly what I teach.

Apps expire. Algorithms glitch. But body literacy? That’s yours for life.

✨ Want more myth-busting, cycle confidence tips, and real talk about fertility awareness? Come hang out with me on Instagram @TrackYourFertility — I share practical posts on cycle tracking, women’s health, fertility and hormones!