We women are only able to conceive for a surprisingly short time every month, so if you’re trying to get pregnant, how do you know that now is the moment to try?
The optimal time to conceive, the so called ‘fertile window’ is open from about 5 days before you ovulate to the day after. You’re most likely to get pregnant if you have unprotected sex every 2 or 3 days during this period, Therefore the first thing you need to know is how long your cycle is so you can work out when you’re ovulating.
There are several ways of pinpointing this. In this digital age, there’s a tendency to think that an app or a gizmo is the ultimate way to track a cycle. In some ways this is so; in others, not so much, so before you rush off and spend your hard earned cash, lets take a look at what’s what.
🌿up to 75% of women trying to conceive use some form of cycle tracking
What your body tells you
The average length of a menstrual cycle is 28 days, but it’s perfectly normal for your own cycle to be anything between 21 and 35 days. Knowing how long it is, and how regular, helps you work out when you’re likely to ovulate. The length of your cycle is calculated from the first day of your period to the first day of the next period.
🌿 The first day of your period is the first day of your cycle
The four cycle phases
Menstrual phase
It’s a common misconception that your period is the end of your cycle. In fact your cycle ends the day before your period begins when your body recognises you didn’t conceive that month. It then starts its monthly house-keeping – shedding the womb lining it had prepared and resetting your hormones ready for you to try again.
Follicular phase
The first day of bleeding is also Day One of your new cycle marking the start of the follicular phase. This is the longest and most variable phase lasting anywhere from 10 to 21 days. Your hormones have cycled back to baseline, and are busy laying down the foundations of a new womb lining and waking up a fresh set of follicles in your ovaries.
Ovulation
As the follicles in your ovary develop they produce increasing levels of oestrogen. When this reaches a specific threshold, it prompts a surge in a hormone called luteinising hormone (LH). This surge causes the dominant follicle to rupture and release its egg into the fallopian tube ready for conception.
🌿Ovulation happens between 10 and 14 days BEFORE your next period begins
Luteal phase
Once the egg has been released, LH acts on the remains of the follicle to create something called the corpus luteum (luteal cyst). This produces progesterone to thicken the womb lining making it receptive to a fertilised egg. This phase is remarkably sable, lasting between 10-17 days, with 14 being the average.
Menstrual phase focus
Two essential biological signs
Your body provides clear, physical clues about its hormonal shifts. By tuning into two specific signs, you can track your cycle for free.
1. Basal Body Temperature – BBT
🌿21% of women trying to conceive monitor their BBT
The hormones of each cycle phase cause your body temperature to rise and fall. Charting these changes is one way you can monitor what’s going on.
- Before Ovulation: During your period and the follicular phase, your BBT sits at its normal baseline (typically 36.1–36.4°C).
- During Ovulation: Slightly before ovulation, you may see a brief, subtle dip, followed by a sudden rise of about 0.3–0.6°C once progesterone kicks in.
- After Ovulation: If you've ovulated, the temperature remains elevated for the rest of your cycle. If you conceive, it stays up; if not, it drops sharply back to baseline, triggering your period.
How to track it: The simplest method is using a precise digital thermometer first thing in the morning when you wake up, before getting out of bed. You can note it in a diary or plot it on graph paper.
🌿Note: Because your BBT doesn't actually rise until 1 to 3 days after the egg is released, it can't predict ovulation in advance. Instead, it confirms that ovulation successfully took place. To predict your window beforehand, you must pair BBT with mucus tracking.
2. Cervical mucus
Often completely overlooked, the monthly changes in your normal vaginal discharge is actually the most powerful real-time indicator that you’re approaching ovulation.
🌿39% of women trying for a baby check for egg-white mucus
Early cycle: For most of the month your cervix produces very little mucus. It’s mainly dry acting as a protective barrier to infection and keeping sperm out of the cervix.
- Approaching Ovulation: As oestrogen rises, the mucus changes from dry/sticky to creamy (like yoghurt), then to wet and watery.
- Peak Fertility: Finally, it becomes clear, slippery, and highly stretchy—looking and feeling exactly like raw egg whites. This fertile mucus protects sperm from the naturally acidic vagina and creates micro-channels to help them swim rapidly up to the cervix.
A fascinating fact:- Under a microscope, the channels in egg-white mucus are exactly the width of a normal sperm head. This acts as nature's first quality control filter, helping to weed out abnormal sperm while simultaneously blocking bacteria from entering the open uterus.
How to check it Simply gather a small amount of mucus on your index finger, touch it to your thumb, and gently pull your fingers apart. If it stretches into a thin, elastic thread without breaking, you are in your peak fertile window.
The world of digital monitors
🌿32% of women trying to conceive use an OPK to monitor hormone levels
So if you have a regular cycle, track your BBT carefully and take heed of your cervical fluid, you know exactly when you’re moving towards ovulation and the optimum moment to try – Free, natural, easy and highly effective.
The question is what apps and gizmos can bring to the party. Studies shown they can absolutely streamllne the process and improve time to conception but they come with distinct trade-offs.
🌿🌿Remember, monitors can only point to the best window for conception; they can’t diagnose underlying fertility problems or guarantee pregnancy.
Choosing the right tool
The marketplace is flooded with options, but they generally fall into two distinct categories: tools that track your hormones via urine, and tools that automate your temperature tracking.
The Digital Monitors Comparison Table
| Monitor Type | How It Works | Pros | Cons |
|---|---|---|---|
| Hormone Monitors / OPKs | Tracks estrogen and LH surges in urine to predict ovulation. | Highly accurate for predicting the exact 24–48 hour window. | Can get expensive with ongoing test strip refills. |
| Wearable BBT Monitors | Continuously reads skin temperature overnight via a band or patch. | Effortless; perfect for erratic sleep schedules. | Higher upfront cost; doesn't predict ovulation in advance. |
| Manual BBT Thermometers | Waking oral temperature measured immediately upon opening your eyes. | Inexpensive; highly reliable for confirming ovulation occurred. | Requires strict routine and uninterrupted sleep before waking. |
Tracking Investment Calculator
Adjust the slider to see how many months you plan to track, and compare the cumulative investment of ongoing test strips versus one-off device costs.
At 6 months, the initial price gap narrows significantly due to ongoing consumable costs.
Track the data: Trust your body
When it comes down to it, fertility is all about the simple rhythms of your own body, and tuning into them is the most natural way to help you conceive. Whether you choose a simple paper diary or the latest high-tech monitor, the most important thing is that it doesn't cause you stress. These tools are simply there to support you along the path to pregnancy—so choose whichever method feels comfortable, and let the routines and data fade gently into the background of your life.
I hope you found this little guide useful and I wish you all the very best on your fertile journey
