Pregnancy & Parenting

When Are You Most Fertile?

Vitabiotics | Published: 13/11/2020

When Are You Most Fertile?

When Are You Most Fertile? Here's How To Track Your Fertility

Are You Trying For A Baby And Want To Know When You Are Most Fertile Each Month? We Look At Different Methods That Can Help You Track Your Fertility, Including Fertility Calendars And Apps

Are you trying for a baby? If so, you might have a lot of questions around fertility, including how long it takes to conceive, what your chances are of getting pregnant, and when you are most fertile each month.

If you want to get pregnant, having sex every 2 to 3 days throughout the month will give you the best chance of conceiving. You don't need to time having sex only around ovulation.

However, it is possible to pinpoint when you are more fertile each month, which can help you to maximise your chances of getting pregnant.

Tracking your menstrual cycle will also help you get to know your body better, be more in tune with and identify the different signs and emotions you may feel at each stage.


How Long Does It Take To Get Pregnant, On Average?

According to the NHS, about 84 out of every 100 couples will get pregnant within a year if they have regular sex and don't use contraception.

Age is also a factor, and a study found that among couples having regular unprotected sex:

  • Aged 19 to 26 – 92% will conceive after 1 year and 98% after 2 years
  • Aged 35 to 39 – 82% will conceive after 1 year and 90% after 2 years

When Are You Most Fertile? Ovulation And Your Menstrual Cycle

By tracking your menstrual cycle, you can pinpoint when ovulation is likely to occur so calculate when in the month you are most fertile.

Your menstrual cycle starts from the first day of your period and is counted up to the day before your next period starts. The length of an average cycle is 28 days, although it is completely normal for this to vary, with some women having shorter or much longer cycles.

During your menstrual cycle, an egg is released from your ovaries, which is what we call ovulation. This usually occurs 10-16 days before your period. The egg then then travels down your fallopian tube and lives for around 24 hours, during which time it must meet a sperm for you to become pregnant.

It’s around ovulation that you are most fertile, and you are most likely to get pregnant if you have sex within a day or so of ovulation. Sperm can also live in your body for seven days, so if you’ve had unprotected sex before ovulation it is possible that it will fertilise the egg when it’s released.

What Is Fertility Tracking And How Can Using A Fertility Calculator Or Fertility Calendar

Help You Become Pregnant?

Fertility tracking involves identifying the signs and symptoms of fertility during your menstrual cycle, so you can work out when you are likely to ovulate and when you are most fertile, and factor this into trying for a baby. It is sometimes known as Natural Family Planning.

If you have regular periods it may take between 3-6 cycles to work out a definite pattern in your fertility. If have irregular periods or there are other factors which may be affecting your menstrual cycle, such as stress or medication, then it might be difficult to predict anything with accuracy. Speak to your doctor if you need help or advice.

These are some of the methods you can use to help you identify the different stages of your cycle:

Recording The Length Of Your Menstrual Cycle

If you have regular periods, it can be helpful to track the length of your menstrual cycle over time and work out at what point you are most likely to ovulate. Ovulation usually occurs 10-16 days before your period, for example women with a 28 day cycle ovulation tend to ovulate at around day 14. This will differ per woman and depending on your cycle.

You can keep a record of dates using a diary or an app that has a fertility calendar. It can also help to be aware of additional changes to your body that may indicate ovulation, such as changes to your cervical mucus (see below).

Using a Fertility Calculator

Fertility calculators are online tools in which you input data around your period – usually start dates and length of cycle – and it will manually work out when you are likely to ovulate. These rely on averages so won’t be accurate if you have irregular periods.

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Recording Your Daily Body Temperature

After ovulation there is a small rise in your body temperature, and your temperature should stay at this higher temperature for around three days. By tracking this information over time you can work out the point at which ovulation should happen, before the temperature change, so factor this into your plans.

To take your temperature you will need to use a digital thermometer, and to record it at the same time every morning, ideally before you get out of bed. Remember that there are a lot of factors that can alter your temperature, from illness to hangovers.

It helps to keep a record of your daily temperature using a special chart or book which you can buy from the chemist, or by using an app. If you do this over time, you should see a pattern emerging.

Noticing Changes to Cervical Mucus

Your cervical mucus changes at different times in your menstrual cycle and can indicate when you are fertile. As your hormone levels rise before ovulation, your cervical mucus will increase from being thick and white to become clearer, slippery and stretchier. It’s often described as egg white cervical mucus, or EWCM.

You can see a guide to what different cervical mucus looks like over on Babycentre.

Using Ovulation Prediction Testing Kits

Ovulation prediction tests - known as OPKs - measure the hormone levels in your urine and can indicate the rise in the luteinising hormone (LH) and oestrogen that surge just before you release an egg. These are similar in look and feel to pregnancy tests, with a symbol or darker line appearing when you are fertile. You can buy a variety of different types of OPKs, including simple paper strip tests, digital tests which give you the result on a screen, and also integrated electronic fertility monitors that measure hormone levels and your body temperature, and analyse data every month.

Fertility Tracking Apps, Fertility Calculators and Fertility Calendars

Fertility tracking apps, calendars and calculators may be useful when you are trying for a baby. Here are useful apps and tools that you can use.


  • What Is It And How Can It Help Track My Fertility? Clue is an intuitive and easy-to-use app that can help you keep track of your menstrual cycle. You input data from the date and length of your period, to different moods, emotions and symptoms including cervical mucus, and it will track these in a circular calendar and help you work out your cycle, when you are most likely to ovulate, and even send you alerts when your period is due.
  • Cost: Free
  • Download here.

Apple Watch Cycle Tracking

  • What Is It And How Can It Help Me Track My Fertility? If you have an iPhone and an Apple Watch, the cycle tracking function on the Health app can be used to track your periods, signs of ovulation and even daily body temperature readings.
  • Cost: Needs an iPhone and Apple Watch
  • More information is here.

Emma’s Diary Fertility Calculator

  • What Is It And How Can It Help Track My Fertility? Emma’s Diary have a free-to-use ovulation calculator, where you input the date of your last period, and how long your cycle usually lasts. It will then give you a date which is an estimate your most fertile time.
  • Remember that this will only give you an estimated date, which might not always be 100% accurate if your periods aren’t always regular or even the same length.
  • Cost: Free
  • Access it here.

Use Your Phone As A Fertility Calendar

  • What Is It And How Can It Help Track My Fertility? If you are not keen on a separate app, you can use the calendar function on your phone to track your fertility by noting down your period each month, and any recognisable fertility signs. This way, over time you can manually work out any patterns in your cycle including the length and when you think you ovulate. If you are tracking your daily temperature, you can also note it here to keep a record.
  • Cost: Free
  • Access it: On your smartphone

If You’ve Read Our Post On How To Track When You Are Most Fertile:

Meet the Author

Gill Crawshaw

Gill Crawshaw

Copywriter / Editor of TalkMum Blog

Gill Crawshaw

Copywriter / Editor of TalkMum Blog

Pregnancy and parenting editor and writer, mum of two Gill Crawshaw is the editor of the TalkMum blog, and a writer who specialises in pregnancy and parenting. With over 18 years experience in digital content creation, she also writes the blog A Baby On Board, which covers the parenting journey. Gill has two tween-age children and lives in south London.

Alexandra Phillips

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