Our search began with a desire to find a way to space pregnancies. Along the way, we discovered that understanding the cycle involved much more than counting days — and that the learning process would also change the way we lived our marriage. Years later, that same experience would help give rise to Natus.
Some choices seem simple when they begin.
When my wife and I decided that we did not want to use condoms, the alternative we found at the time was hormonal contraception.
It seemed like a practical solution for a couple who wanted to space a pregnancy.
Over time, however, questions arose that made us look again at that decision.
My wife began experiencing episodes of migraine and problems related to varicose veins. There were appointments, questions and investigation.
We did not have the medical knowledge to conclude on our own that a particular condition had been caused by the medication. But the whole experience made us ask whether hormonal contraception was still the best choice for us.
That was the beginning of our search for another way to approach family planning.
The familiar calendar method
Our first attempt will probably sound familiar to many people.
The calendar method.
Dates, calculations, estimates and the expectation that the next cycle would behave roughly like the previous ones.
For a period of time, that was how we tried to organise ourselves.
In practice, we treated the cycle almost like a calendar: some days seemed safer, others less so, and we tried to make decisions from those calculations.
Looking back, I can see how different that was from what we would later learn.
But at the time, it was what we knew.
It was also our first attempt to take shared responsibility for planning our family.
After our first child, we discovered something different
After the birth of our first child, we were introduced to the Billings Ovulation Method®.
Until then, I knew very little about fertility awareness.
And I suspect I had the same reaction many people have when they first hear about it:
“Isn’t this just another calendar method?”
I soon discovered that it was not.
The idea was not to predict what would happen that month simply by counting days from previous cycles.
My wife needed to learn to observe her own body and recognise what was happening throughout the cycle.
And we would need to learn together how to deal with that information.
As a Catholic couple, there was another important dimension to that decision.
At that point, vasectomy and other contraceptive methods that, according to our understanding of our faith, we did not wish to use were not paths we were considering.
We wanted to find a way to space pregnancies that was also consistent with what we believed.
That is how we began.
The beginning was much harder for me than I expected
Today it is easy to write:
“We started using the Method.”
Living through the beginning was very different.
First, there was the difficulty of understanding it.
There were observations, records and rules that had to be learned.
It was not enough to look at a calendar and count a few days.
My wife had to learn to observe.
I had to learn to understand what she was observing.
And both of us had to understand how that information would become part of our decisions as a couple.
At first, everything seemed to require far more attention than I had imagined.
But there were also difficulties that were not really about the rules themselves.
Sharing our intimacy with people we had only just met
To learn properly, we needed support.
And that meant sharing information that until then had belonged almost entirely to the two of us.
Cycle observations.
Marital relations.
Questions.
Intimate situations from our married life.
Intellectually, I understood why that guidance was important.
In practice, it was not easy.
We had only just met those people and suddenly we were expected to open up an extremely private part of our lives.
There was embarrassment.
There was a sense of exposure.
And there was the natural thought:
“How much do we need to share?”
or:
“How will this person receive something so intimate about us?”
For me, that required trust.
And trust does not appear automatically just because someone becomes your instructor.
It had to be built.
As we understood the process better, got to know the people supporting us and saw the respect with which those details were handled, the discomfort gradually eased.
But that experience stayed with me.
Perhaps that is why, years later, certain questions became so important when I began thinking about Natus:
Who can access this information?
Does access need to be permanent?
Does the person clearly understand what they are sharing?
Can they withdraw access when they want to?
At the time, I was not thinking about software architecture, permissions or digital privacy.
I was simply learning, as a husband, that information about fertility, health and intimate life deserves special care.
And then there was abstinence
For me, however, the greatest difficulty was probably something else.
Abstinence.
That deserves to be said because family planning is sometimes discussed so technically that it can sound as though a couple simply presses a button.
There is no button.
I was a husband.
I loved and desired my wife.
And at certain times, the choice we had made required me to wait precisely when I did not want to wait.
On paper, a rule may fit into a few lines.
Inside a marriage, it involves desire, expectation, frustration, dialogue and self-control.
There were moments when I found it difficult.
There were moments when I wished everything were simpler.
And there were moments when understanding a rule intellectually did not make it any easier to live.
That part of the story is real too.
I do not want to present our experience as if everything had been simple, light and perfectly understood from the beginning.
It was not.
We learned over time.
The cycle stopped being only “her issue”
It was during that process that something began to change between us.
Before, it was easy to make family planning almost entirely a woman's responsibility.
She took the medication.
She followed the cycle.
She physically carried much of the impact of decisions that belonged to both of us.
As we began living the Method as a couple, that started to change.
I needed to know where we were in the cycle.
I needed to understand what she was observing.
I needed to take part in the decisions.
And I also needed to accept part of the sacrifice those decisions could require.
The cycle was still her cycle.
But planning our family became clearly our responsibility.
For me, that was an important change.
She learned more about her cycle. And I learned more about her.
Over time, what had initially seemed like a large amount of information and rules began to make more sense.
My wife became more attentive to what was happening in her own body.
Changes that might once have gone unnoticed began to be observed.
And by accompanying that process, I also began to understand better what she experienced throughout the cycle.
I do not want to romanticise it.
Knowing the cycle better did not remove the difficulties of marriage.
And abstinence did not magically become easy because we understood the Method better.
But the experience created conversations that probably would not have existed in the same way before.
We needed to talk.
We needed to decide together.
We needed to learn to wait together.
And little by little I realised that what I had initially seen almost entirely as a restriction was pushing us to develop something much larger:
shared responsibility.
Then we used the same knowledge for a different purpose
For part of our journey, we used what we had learned because we wanted to space another pregnancy.
But around eight years ago, we made a different decision.
We wanted a second child.
It was an interesting experience because the knowledge we had learned while trying to space a pregnancy became part of another stage in our family.
This time, we followed the cycle hoping for pregnancy.
We used what we had learned about cycle observations while trying to conceive.
And we had the immense joy of conceiving our second child.
I do not say this as a promise of results for other people.
Every couple has its own story, and many factors are involved in pregnancy.
For us, however, it was deeply meaningful.
The same knowledge of the cycle that had once been part of our decisions when we wanted to wait was also present when we decided to welcome another pregnancy.
“That’s just the calendar method”
Almost ten years later, I still hear very similar reactions when I share our experience.
One of the most common is:
“That’s just the calendar method.”
Sometimes there is a small concession:
“It’s an advanced calendar method.”
And there is also the joke:
“Tell me in nine months how well that worked.”
Today, I usually hear these comments calmly.
I understand the association.
For someone familiar only with calendar-based methods, any natural approach to fertility can seem like an attempt to identify which days of the month are “safe”.
But that was not our experience.
Counting days and hoping that the next cycle would repeat the previous ones was very different from observing what was actually happening in the current cycle.
Perhaps that is why I find it so difficult to summarise these years in a single sentence.
They were not ten years of doing calculations.
They were years of learning to observe, record, talk and make decisions.
We also encounter different interpretations among Catholics
There is another conversation that comes up often.
I know people who share the same Catholic faith but understand some of the Church's teachings on family planning differently.
Some use other methods to space pregnancies and present their own reasons and interpretations for those choices.
I am not writing our story to judge them.
Nor do I believe a personal testimony needs to become an argument about other people's lives.
I can only speak about what we chose to live.
Within the way we understand our faith and our marriage, we decided to follow this path.
Looking back after all these years, I can see that it brought things into our relationship that I had never imagined when we began.
For a while, we practically kept everything in our heads
There is an interesting detail in this story.
After so many years, we reached a point where we were applying much of what we had learned almost from memory.
We talked.
We generally knew the context of the cycle.
We made our decisions.
But we did not always keep an organised record.
Then, on one occasion, my wife visited a Catholic gynaecologist who also works as an instructor and speaker on the Method.
During the appointment, she gave my wife a chart.
The instruction was to complete the records and bring it back at the next appointment.
When she came home, my wife looked at me and asked a very simple question:
“Do you have an app I can use to record this?”
The question stayed in my head.
My first reaction was not:
“Let's find one.”
It was:
“I can build one.”
In truth, the idea was already almost ten years old
What is interesting is that the idea did not really begin at that moment.
When we first started using the Method nearly ten years earlier, the mobile app landscape was very different from what it is today.
I had already thought about building something that could help with this kind of follow-up.
I even began studying a programming language specifically because I wanted to try to create a tool of this kind.
But at the time, I did not yet have enough experience.
I started.
I studied.
I encountered the natural difficulties of someone learning.
And I could not turn the idea into a working product.
The project stopped.
But the idea remained.
“If apps already exist, why build another one?”
That is a completely fair question.
Today there are many apps related to cycles, fertility and women's health.
So why not simply use one of them?
For me, the answer lies in niche and purpose.
I like to build products by thinking first about what they need to respect.
There are excellent apps designed for very broad audiences and later adapted for different cultures, beliefs and needs.
That is a legitimate approach.
But I wanted to try the opposite direction.
I wanted to begin with a specific reality that I knew from personal experience.
A reality in which faith, marriage, fertility, intimacy, guidance and recording were connected.
My goal was not to build an app that would tell a woman what she should conclude about her cycle.
I wanted to build a tool that respected what she had actually observed.
One that recorded.
Organised.
Preserved history.
Worked when there was no connection.
Allowed a husband to participate.
Allowed follow-up to be shared with an instructor when the couple chose to do so.
And treated intimate information with the level of care I would have wanted when we ourselves began this journey.
My Catholic faith is part of the way I think about these choices.
That does not mean Natus was created only for Catholics or that someone needs to share our beliefs to use it.
It means that when I build something, I like to begin from certain principles and remain faithful to them.
Ten years later, I could finally build what I had imagined
When my wife asked that question about an app, the old idea returned.
But this time something had changed.
I had more experience.
I had already built other products.
I understood better how to turn a need into interfaces, data, rules, permissions and features.
What I had not been able to build years earlier finally seemed possible.
So I started.
What might have been only a small tool for our own home began to grow.
Daily records.
History.
Cycles.
Charts.
Offline use.
Synchronisation.
Husband participation.
Instructor follow-up.
Reports.
Privacy.
Access control.
The ability to revoke access that had previously been granted.
And throughout development, one decision remained at the centre of the product:
Natus should record what the person enters without taking on the role of automatically interpreting their fertility.
Some Natus decisions came directly from our own experience
When we decided that another person's access to a follow-up should depend on authorisation, that was not just a feature to me.
I remembered how uncomfortable I had felt when we had to share intimate details of our lives with people we were only beginning to know.
When we thought about allowing that access to be revoked, I remembered it again.
When we decided that a record should remain tied to what the person actually entered, there was a reason.
When we chose not to place an automatic prediction in the app telling a woman when she was fertile or when she had ovulated, there was another reason.
Natus gradually became a digital product.
But many of its decisions were born from an experience that began long before the first line of code.
It was not only about learning a method
When I think about these nearly ten years today, the most important part of the story is probably not in a rule.
It is not in a chart either.
And it is not in memorising certain concepts.
It is in what the process required from us.
My wife learned to know her own cycle better.
I had to learn that family planning was not a responsibility I could simply leave on her shoulders.
We had to talk.
We had to understand.
We had to wait.
At times, we had to give something up.
We also had to learn to trust other people enough to ask for help and guidance without forgetting that our intimacy still belonged to us.
And we had the joy, at another stage in our lives, of using what we had learned while hoping to welcome another child.
It was not a perfect journey.
It was a real one.
With questions.
Difficulties.
Learning.
And growth.
Perhaps that is why, when someone reduces everything to the phrase “calendar method”, I realise how difficult it is to express in a few words what we actually lived.
For us, it was never simply about counting days.
It was also about learning to live a decision as a couple.
Ten years later
If someone asked me today what the greatest change from this experience was, I probably would not simply say that we learned a different way to follow the cycle.
My wife came to understand more clearly what was happening in her body.
I became involved in an area of our life that could easily have remained only her responsibility.
And we learned that fertility, sexuality and family planning did not have to be individual matters inside a marriage.
They could be ours.
We are still a real couple.
We still face challenges.
But there is a significant difference between the man who began this journey struggling even to understand the rules and the man who can now look back and see what the whole process produced in our relationship.
We did not only learn more about the cycle.
We learned more about one another.
And Natus became the fulfilment of an old dream
Perhaps that is why I relate to Natus a little differently.
It was not born simply because one day I identified a market opportunity.
It grew out of our attempts to find a way to live family planning.
The calendar method.
The learning.
The difficulty of abstinence.
The discomfort of sharing intimate information.
The experience of following the cycle for years.
The decision to try for our second child.
That old attempt to learn programming so I could build something I was not yet capable of finishing.
And, many years later, a simple question from my wife:
“Do you have an app I can use to record this?”
This time, I could finally answer:
“Not yet. But I can build one.”
And I did.
For me, Natus is also this:
a project that remained quietly stored away for years until experience, technology and purpose finally met.
Discover Natus
Natus is a private space for recording and organising cycle observations, reviewing history and sharing follow-up only with authorised people.
The app does not predict ovulation, does not automatically determine fertile or infertile days and does not replace learning a method or professional guidance.
Its purpose is simpler:
to help people clearly record what was actually observed while keeping control of their own records.
Discover Natus →
About this story
This article presents a personal experience of the author and his wife over a period of approximately ten years.
References to medication, symptoms, pregnancy and family planning describe only the couple's own experience and do not constitute medical advice or a guarantee of results for other people.
Learning and applying the Billings Ovulation Method® should be done through official sources and appropriate guidance.
Natus is an independent recording and organisation tool and does not replace professional advice or formal education in fertility awareness methods.
Guilherme Silva *Natus developer*
