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    When are you most fertile?

    On this page
    1. When am I most fertile?
    2. What can affect my fertility?
    3. What are fertility tests?
    4. Can I test my fertility at home?

    Reviewed by Dr Bhavini Shah

    Are you planning on having a baby? It’s estimated that 3.5 million people have difficulty conceiving in the UK. So, you're not alone if you or your partner is trying to get pregnant.

    Checking in on your hormonal health can be helpful. Not only for your fertility but also for your general wellness. In this article, we look at when women and men are most fertile and the fertility tests available.   

    When are you most fertile

    When am I most fertile?

    Fertility for men and women differs. It’s influenced by age, lifestyle and where you are in your menstrual cycle.

    When are women most fertile?

    In terms of age, females are biologically able to reproduce from the beginning of their menstrual cycle. The average age a girl experiences her first period is 12 years of age. Although girls can expect their first period between the ages of 10 and 16.

    Studies have shown that women are most fertile between the ages of 20 and 24. However nowadays more women are having children in their late twenties and early thirties:

    • By the age of 30, a woman's chance of conceiving is 20% per month
    • At the age of 40, this chance is reduced to 5% 


    Biologically, females are most fertile during the six-day window in which ovulation occurs. For a woman with a 28-day cycle, this occurs between day 14 and day 21. Ovulation occurs when the  egg is released from the fallopian tube and travels to the uterus (womb).

    It is recommended that you have sex every 2 to 3 days especially  around the time you are ovulating – this is usually 12 to 16 days before your period starts. Sperm can live in the womb for up to five days, so fertilising an egg is possible. Find out more about the early signs of pregnancy.

    When are men most fertile?

    It is widely believed that men remain fertile throughout their lifetime. While they may not experience a male equivalent to the menopause, the quality of a man's sperm continuously declines from 20 years of age. By the age of 40 the quality of sperm begins to decline more rapidly.

    Find out more about what can impact male fertility.

    How long it takes to conceive

    Puberty in males can begin at the age of 9 and continue until the age of 16. During puberty, the testes develop and testosterone and sperm production begins. Some claim that sperm quality changes as men age as does the time it takes to conceive successfully: 

    • Before the age of 25 it takes an average of 5 months
    • After the age of 45 it may take up to 5 times longer 

    The “fertile window” that women experience is not experienced by men in the same way. Sperm is continuously produced and stored in the testes throughout their lifetime.

    When you’re trying for a baby you and your partner should aim to have regular sex, every 2-3 days. This can improve the chances of successful conception.

    What can affect my fertility?

    Some couples can get pregnant quickly and for others it may take longer. About 1 in 7 couples may have trouble getting pregnant. Fertility issues can affect one person in the couple or both, common risk factors for infertility include:

    • Age
    • Smoking
    • Your weight
    • Medications
    • Recreational drugs  

    What are fertility tests?

    Fertility tests can investigate issues that may be affecting your chances of getting pregnant. 

    “If you’ve been trying to conceive for over a year you should speak to your GP. If you’re a woman aged 36 or older, or you’re aware you may have fertility issues see your GP sooner.” - Dr Bhavini Shah

    Your GP can investigate risk factors, offer tests or scans and possible treatments. Fertility tests may include:  

    Women’s fertility tests

    • Blood test to check your hormone levels
    • STI test to see if you have chlamydia as this STI can affect your fertility
    • Scans to check your ovaries, uterus (womb) and fallopian tubes
    • An x-ray combined with an injection of special dye to check for any blockages in your reproductive organs
    • Laparoscopy (keyhole surgery) where a camera is used to look at your ovaries, uterus and fallopian tubes more closely  

    Men’s fertility tests

    • Sperm health test to check for quantity and quality of sperm
    • Blood test to check testosterone levels. Testosterone is linked to sex drive and sperm production
    • Chlamydia test as this STI can cause infertility  

    Your GP can give you more information about the different types of tests available. Including what may be the best one for you.

    Can I test my fertility at home?

    If you or your partner are trying to get pregnant there are different tests you can use that may show how fertile you are. However, it’s recommended that you also speak to your GP.

    Types of home fertility tests include:

    • At-home blood tests – these examine your hormone levels such as follicle stimulating hormones and thyroid function
    • Anti-Mullerian Hormone (AMH) test - your level of AMH indicates how many eggs you have in your ovaries.
    • Ovulation tests - can tell you on which days you’re ovulating and have a higher chance of getting pregnant
    • Sperm tests - check your sperm count, motility and shape of sperm  

    If you have completed an at-home fertility test and are worried about the results speak to your doctor. Fertility tests should be combined with expert healthcare advice.


    Learning more about your fertility, including when you’re most fertile can help with family planning. Home tests can be a convenient and confidential way to check your fertility status. However, you should also seek advice and guidance from your doctor.


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    Authors and editors

    • Reviewed and updated by

      Dr Bhavini Shah
      GMC number: 7090158
      Date reviewed: 21st May 2024

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