Fertility Window

ben bunting BA(Hons) PgCert Sport & Exercise Nutriton  Written by Ben Bunting: BA(Hons), PGCert.


One of the most important steps of trying to start your family and become pregnant is to understand the fertility window.

You may or may not be aware that there is only a certain time of the month in which you may be able to successfully conceive. [1]

This means there is a window in which you should be aiming to have sex in the attempt of getting pregnant.

But how do you know when this window is? And what do you need to know about fertility to help boost your chances?

This article will help answer these questions and more.

Knowledge is one of the most powerful tools you’ll have at your disposal. So, when you have become educated in all things fertility, you will be able to focus your attention on other parts.

In this article, we will cover the following topics:

  • Defining what fertile actually means
  • Facts about the menstrual cycle
  • The process of pregnancy and being pregnant in general
  • How long your fertility actually lasts
  • When a woman is in her fertility window
  • The best time to get pregnant in this window
  • Everything you will need to know about a man’s fertility
  • How to know when a pregnancy has occurred
  • What you need to know about allergies and pregnancy
  • How age can affect fertility
  • Conclusion of the article

This article will help you understand all things fertility, how Fertiligy can help in some regards, and how you will be able to help yourself get the best chance of conceiving a child.

Defining Fertile

defining fertility

Firstly, it will go a long way for you if you understand what being fertile actually means. Essentially, it refers to the ability of both men and women being able to reproduce.

This means the ability to have children and conceive in general, you can read out more detailed article about the definition of fertility, here

Women go through something known as the menstrual cycle, which is their bodies way of managing eggs and follicles.

Follicles are a sac within the ovaries of a woman that is filled with fluid.

Within this fluid, immature eggs develop into mature eggs. When a follicle grows to an ideal size, ovulation occurs, which then allows it to rupture and release the egg.

When a woman begins puberty, she will start with around 300,000 to 400,000 follicles, with all of them having the potential to release eggs for fertilization.

Some women can have fertility treatment if they are struggling with maturing their eggs, but the status and size of the sacs will be important in finding out how they can be treated.

Usually, this will be done through an assessment. A follicle will usually have one egg inside to develop before it ruptures.

There are different fertility solutions that will help in boosting the fertility chances of both male and females in either natural ways or with more scientific ways.

It’s possible that it could be just one partner who is struggling with their fertility, or it could be both.

It’s important that you get any problems identified as early as possible.

In most cases, a couple that is below the age of 40, and especially so in their 20s, will be able to conceive a child at the first attempt, or at least within the first month of trying.

Facts About The Menstrual Cycle

The menstrual cycle is quite complex and is controlled by different types of hormones and glands in a woman’s ovaries.

There are a few different stages of the cycle, the first being menstruation; this is otherwise known as a period.

This occurs when the uterine lining starts to shred, leaving estrogen and progesterone levels low. [2]

From there, the follicular stage will begin. This can take place from the first day of the period when the menstruation begins and leads to ovulation.

As briefly touched upon earlier, the follicular phase is all about the follicles preparing for the eggs to be released.

This will happen once they’ve built up enough and have enough estrogen. [3]

The proliferative stage is when the period ends. This will mean that the uterine lining will build back up and prepare itself for the next time it needs to shred.

Ovulation occurs when the egg is released from the ovary, somewhere around the mid-cycle of the menstrual process.

Again, estrogen will be high before this happens, before dropping back down again post ovulation. [4]

The luteal phase refers to the time that takes place between ovulation and before the start of being menstruated.

This is when the body will prepare itself for a potential pregnancy. In here, progesterone will be produced in high quantities for two weeks before dropping once again. [5]

The secretory process is where the uterine lining starts to produce certain natural chemicals that will help to support an early pregnancy.

If not pregnant, then it will prepare the lining to break down and shed once again with serum levels of 17-beta-estradiol and progesterone decreasing rapidly. [6]

If you haven’t guessed, then you should know that this menstrual cycle only refers to females, with no males going through this, as they have a completely different reproductive system.

This cycle repeats itself each month, meaning that the body is preparing itself at all times to be fertile and be pregnant.

However, you will need to be aware of the window that gives you the best chance of being pregnant, which we will cover later on within the article.

For now, we will move on to the pregnancy process.

The Process Of Pregnancy

process of pregnancy

Once a fertile woman and a fertile man have come together to successfully start a pregnancy, it will be in both of your interests to be aware of what actually goes on in the pregnancy process.

This will give you the best chances of making it through the process happily.

In most cases, a typical pregnancy will last up to 40 weeks from the first day of when your menstrual period ends to the birth of your baby.

The pregnancy process is oftentimes broken down into three different stages, otherwise known as trimesters. [7]

The first trimester starts from week one and ends after week 12. From there, the second trimester will start, which lasts until week 26.

The third trimester starts from the following week and will end once the baby arrived.

You and your partner will usually be given a due date for when the baby will arrive, but this isn’t always accurate.

How Long Does Fertility Last?

Whilst men and women are fertile for large portions of their life, and there are certain times and ages that are best to aim for.

For example, fertility for men means that they will be able to produce semen almost any day, especially more so if it has been a while for them.

Whereas for women, whilst they can also have sex at any other point that they want to, there will be certain times that their bodies will be able to reproduce.

For a woman, they may last until their 50s until they enter menopause. [8]

Theoretically men may be able to produce sperm and reproduce up until their 80s, however, fertility reduces aroud 40 years of age as the semen quality becomes imapired. [9]

It all depends on the individual and any underlying or developing health conditions. 

When Is A Women In This Window

Whilst a woman will be in her menstrual cycle each month, allowing for optimum chances of pregnancy, there is a particular window to aim for.

This window usually lasts for around six days or so, including the day of ovulation. [10]

Sperm can live inside the female reproductive system for up to five days.

This means that sperm could be inside the reproductive system before any egg cell or follicle even releases.

Identifying this window will allow you to know the optimum time to have sex.

It is also possible that a woman could become pregnant even during her period. It is less likely than normal but not impossible. [11]

Cycles for menstruation will vary from woman to woman, meaning it is hard to understand fully what your personal and unique situation will be.


The Best Time To Get Pregnant In This Window

Within this actual fertile window, you can narrow it down even further to find the best time to get pregnant.

Whilst sperm can last longer, as mentioned earlier, an egg cell will start to deteriorate much quicker, starting when ovulation occurs.

➡️READ: Natural treatments for male infertility

In about 24 hours, the egg cell will die, with the hours running up to it increasing the drop in quality, making successful conceiving more unlikely. [12]

That’s why experts suggest that the best time to attempt to conceive is to have sex up to 6 days right before ovulation happens or on the day of ovulation. [13]

This means you will have to work to try and predict ovulation so that you can plan accordingly.

For males, you will need to make sure they are as fertile as they can be. They can increase their chances by taking fertility products; this will help to enhance male fertility naturally.

The best time to predict ovulation is by using your body. Your body is naturally designed to give you signs that showcase your fertility.

For example, a rise in basal body temperature will be an indicator that you’re entering this stage.

If this happens to arrive at the same time in your cycle, then you will be able to plan for the following months in finding the best time. [14]

There are also tests available that can help pinpoint your ovulation stage in your cycle, but the results may vary from person to person and shouldn’t be relied on as fact. [15]

The consistency of cervical mucus can also be an indicator in identifying your ovulation cycle, allowing you to narrow down your fertile window.

Once you’ve got all this information, you will be able to effectively plan a pregnancy.

Everything You Need To Know About A Mans Fertility

fertility window

Of course, it’s not just women who need to consider their fertility. Whilst men can last longer than a woman with their fertility, they are still prone to infertility.

Almost one in seven couples will have some sort of infertile problem between them, even if they are following the window and doing everything as right as they can.

Data suggests that one third of fertility issues within a couple are male related, and one third due to both parties suffering from fertility issues. [16]

Male infertility can play a partial role in this.

There are several reasons as to how a male could become infertile. In 10-15% of cases this comes from low sperm production. [17]

This will come from the testicles, which primarily kick in when the male sex organs are formed and grow.

This typically happens during puberty and adolescence. 

In order to produce sperm, a male must have at least one testicle that works correctly.

Also, the body has to be making enough testosterone and other vital sex hormones in order to trigger sperm production and keep it going over time. [18]

Sperm also needs to be able to get into the semen carrier itself.

When sperm has been created in the testicles, they will be transported through delicate tubes and then combined with semen.

There needs to be enough sperm in the semen, as a lower count will decrease the odds that one of the sperm will fertilize a woman’s egg successfully. 

Typically speaking, a low sperm count is considered when it is fewer than 15 million sperm per milliliter of semen.

The sperm and semen themselves will need to have good mobility. Otherwise, it will be considered abnormal and unable to penetrate or even each egg. [19]

It could be that your hormones, particularly your testosterone, is lower, which can affect sexual desire or even sperm production.

However, hormones aren’t the problem in 97% of infertile men, meaning it’s not likely to be the reason.

It’s possible that some men will create abnormal antibodies inside their systems that attack the sperm when it’s on the way to the egg.

Of course, this will stop it from reaching a female and prevent pregnancy. [20]

Other men are capable of getting the sperm made but have trouble reaching it to the ovaries for various different reasons.

For example, alcohol has been linked with male infertility, with evidence showing that it can directly lower the sperm count.

You can help combat these effects of lower sperm count by adjusting your lifestyle.

That could mean cutting down on amounts of alcohol could help bring this number up, or changing your diet could also help. [21]

Consider speaking to a health professional or dietician in order to find a suitable plan to help you along is recommended.

It is something you can manage and improve on your own, but extra help will go a long way.

It’s not just alcohol that could cause fertility issues. Some steroids have been shown to cause infertility in some men. It can even cause harm to the chances of conceiving a child for both males and females, so cut down when you’re trying.

If you are still struggling to conceive a child, consider looking into Fertiligy.

We have a range of different fertility products to help boost a male’s fertility naturally, with proven nutrients that are plant-based and safe.

How To Know When A Pregnancy Has Happened

There will be early symptoms that you can look out for, as a woman’s body will start to change very quickly within the first month of pregnancy.

It is, however, also possible that symptoms will not be noticeable, so don’t be too disheartened.

Early signs include periods being missed or the cycle disrupting, an increased need to urinate, breasts swelling up and becoming more tender, morning sickness and even fatigue. [22]

There will be different tests you and your partner can take to find out for sure.

This is one of the best ways to find out, as even if they’re not 100% accurate, they will be very close to it.

It would help if you waited until a period has been missed before taking a pregnancy test, as it takes time for the hormones that tests detect to build up.

It’s possible to receive negative tests even if you’re positive if you do it too early.

How Age Can Affect Fertility?

As we mentioned earlier, age is a big issue for fertility. Women will be able to reproduce much easier in their 20s than they would in their 40s.

For men, they will mostly be able to healthily produce semen and sperm up until they turn 80 or so, but fertility is still at its peak for males around 30 years old. [23]

Still, again it will depend on any ongoing infertility issues and the individual themselves.

The older you get, the lower your chances of giving birth are not impossible but potentially more difficult.


To sum up, you should know everything you need to know regarding the science behind fertility, reproduction, ovulation and the menstrual cycle, as well as how to time the fertility window.

It will come down to you to find the best time to try and conceive, but you can also use Fertiligy products to help boost your chances, especially for males.

Whilst the window of opportunity does help increase your chances for two fertile people to conceive a child, it’s not the only way.

It can happen at any other time, even during a period, so keep trying and seek medical assistance if you’re struggling.

It’s also important to note that the window doesn’t guarantee success; you will have to work at it together to ensure you are on the same side.

fertility window


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[‌2] Center for Reproductive Health. (n.d.). The Menstrual Cycle. [online] Available at: https://crh.ucsf.edu/fertility/fertility_cycle.

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‌[10] Wilcox, A.J., Dunson, D. and Baird, D.D. (2000). The timing of the “fertile window” in the menstrual cycle: day specific estimates from a prospective study. BMJ : British Medical Journal, [online] 321(7271), pp.1259–1262. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC27529/.

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[17] American Urological Association (2008). A basic guide to male infertility: how to find out what's wrong. Retrieved June 11, 2012, from https://urology.ucsf.edu/sites/urology.ucsf.edu/files/uploaded-files/basic-page/a_basic_guide_to_male_infertility.pdf

[18] Smith, L.B. and Walker, W.H. (2014). The regulation of spermatogenesis by androgens. Seminars in Cell & Developmental Biology, 30, pp.2–13. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4043871/

[‌19] NHS Choices (2019). Low sperm count. [online] Available at: https://www.nhs.uk/conditions/low-sperm-count/.

‌[20] Antisperm antibodies in infertile men and their effect on semen parameters: A systematic review and meta-analysis. (2015). Clinica Chimica Acta, [online] 444, pp.29–36. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0009898115000558?via%3Dihub [Accessed 2 Aug. 2021].

[21] Salas-Huetos, A., Bulló, M. and Salas-Salvadó, J. (2017). Dietary patterns, foods and nutrients in male fertility parameters and fecundability: a systematic review of observational studies. Human Reproduction Update, 23(4), pp.371–389. Available at: https://academic.oup.com/humupd/article/23/4/371/3065333

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