When are you most fertile during your cycle

Knowing when you’re most fertile can be helpful whether you’re trying to conceive or wanting to avoid pregnancy. A woman can only get pregnant on a few days during their menstrual cycle – this is known as the fertile window.

Tracking and understanding this window gives you an idea of when you’re most or least likely to get pregnant and it can also help you better understand your body.

Male fertility doesn’t change in the same way but, like women’s fertility, it decreases with age and is closely connected to sperm health.

What does fertility actually mean?

Fertility is your ability to conceive children. Around 80% of partners will get pregnant within a year if they have regular sex without contraception.

Both male and female fertility declines gradually with age. A woman’s fertility declines significantly from about the age of 37. Male fertility depends more on sperm count.

When am I most fertile and what is a ‘fertile window’?

Your fertile window is a select number of days during your cycle when you’re most likely to get pregnant. This window depends on the average length of your menstrual cycle – which varies a lot for different people – but is usually around the middle of your cycle.

Your fertile window is around the time of ovulation (when the egg is released from the ovary). The fertile window includes the 5 days before ovulation, the day of ovulation and the day after.

Sperm can survive for several days in the body, which is why your fertile window includes a few days before ovulation. Having unprotected sex during this time gives you the best chance of getting pregnant.

How many days am I fertile for each month?

Most people have around 5-7 fertile days each month. Outside this fertility window, your chances of getting pregnant are low.

How can I calculate my fertile window?

You can use an ovulation calculator, which works by inputting the date of the first day of your last period and your average cycle length.

It’s possible to track your fertile window using a period tracking app. Or you can buy an ovulation predictor kit from a pharmacy to track your changing hormone levels.

What’s the difference between ovulation and fertile days?

Ovulation is when your ovary releases an egg. This happens around 10-16 days before your next period starts, although everyone’s cycle is individual.

Fertile days are the days during your menstrual cycle when you have the ability to become pregnant if you have unprotected sex. The day you ovulate is one of your fertile days.

What are the common ovulation symptoms?

There are some common symptoms that can help you tell when you’re ovulating.

  • Cervical mucus – you might notice wetter or more slippery mucus around your time of ovulation.

  • Body temperature – your body temperature rises slightly just after ovulation, which you may be able to detect with a thermometer. This is how some natural family planning contraceptives work.

  • Breast tenderness or mild cramps – some women may experience these symptoms when ovulating but they’re not a reliable way of predicting ovulation.

Can you get pregnant on your period?

Getting pregnant on your period is very unlikely. This is because you can’t ovulate during your period, and it’s around your ovulation time that you’re most fertile.

While women aren’t able to conceive during this time, sperm can survive within the body for up to 5 days, so depending on the length of your cycle, there’s still a small chance.

It’s also important to keep in mind that bleeding between periods is not uncommon. Bleeding or spotting for any reason other than a period won’t protect you from pregnancy.

If in doubt or you’re trying to avoid getting pregnant, use a reliable contraceptive.

When should I speak to a doctor?

Speak to a doctor if:

  • You’ve been trying to conceive for over a year and are concerned about fertility issues
  • You think that you might be pregnant (taking a test is the best way to confirm this)
  • You’re experiencing irregular or painful periods, or changes to your menstrual cycle

This article has been medically reviewed by Dr Elisabeth Rosén.

If you’re trying to get pregnant, one of the most important ways to increase your chances of conception is to understand when your most fertile days occur during your menstrual cycle. But what’s the best way to figure that out?

It all starts with understanding the fertility basics, especially when it comes to what fertility is and how ovulation plays a role. There are signs you can watch for and tools you can use to narrow down your most fertile days so you can plan your baby-making sessions to match.

Read on to learn more about fertility and ovulation, and how understanding both can help increase your odds of conceiving.

The basics: Understanding fertility and ovulation

What is fertility?

When we say “fertility” we mean your body’s ability to conceive.

What is the fertile window?

Your fertile window is the time during your cycle when your chances of conceiving are at their highest.

When is the fertile window?

Your fertile window occurs midway through your cycle.

The length of your menstrual cycle helps determine the length and timing of your fertile window. Your period marks the first day of your cycle – the average cycle length is 28 days, but it can range from 21 to 35 days. So, depending on your cycle, your fertile window can be anywhere from six to 10 days in length.

What is ovulation?

Ovulation is the release of a mature egg from your ovary.

When does ovulation occur?

Ovulation happens during your fertile window and it starts the clock on your “ovulation window”, which is the roughly 24- to 72-hour time period when egg fertilization can occur.

So, how many days after your period is ovulation? Depending on your cycle, ovulation may occur between six and 20 days after your period starts.

How many days do you ovulate?

A normal ovulation cycle lasts about 24 hours each month. Once an egg is released it’s viable for fertilization for about 12 to 24 hours.

How do you know when you’re ovulating?

The best way to know when you’re ovulating is to take steps to pinpoint your fertile and ovulation windows, which we’ll get to in the next section. But you may also experience one or more of the following ovulation symptoms:

  • Heightened sense of smell
  • Breast soreness and tenderness
  • Mild cramping
  • Light spotting or discharge
  • Increased sex drive
  • Changes in the position and firmness of your cervix
    • During ovulation, your cervix rises to the top of your vagina and becomes softer and moister. This makes it easier for sperm to travel through your cervix and into your uterus.

Identifying your fertile window and ovulation window

While an egg needs to be fertilized within 12 to 24 hours of its release, sperm can live for up to five days within your reproductive tract. That’s why identifying your fertile and ovulation windows is so important. Knowing this information can help you and your partner time sex for when your chances of getting pregnant are highest.

Step 1: Track your menstrual cycle to understand what’s normal for you

Your menstrual cycle – and the symptoms you experience throughout it – are unique to you. So, if you’re preparing for pregnancy, getting familiar with your cycle and identifying any patterns are super important for figuring out your most fertile days.

The best way to do this is to start tracking your menstrual cycle and the symptoms you feel each day. For starters, this will help you determine your cycle’s average length. Remember, your cycle length helps determine the timing of your fertile window.

Tracking your symptoms such as increased or decreased sex drive, mood, cramps, bloating, tender breasts, body aches or changes in cervical position, help you identify patterns at different points in your cycle – including ovulation.

Where can you keep track of all this information? While you can certainly use pen and paper, there are mobile apps such as Fertility Friend and Clue specially designed for this.

Step 2: Track your ovulation to pinpoint your most fertile days

Before and during ovulation, your body experiences certain changes – some you may physically notice and track in your app, but other changes can’t be detected without the right tools. Depending on how long you’ve been trying to conceive, one or more of the following methods can be used to help identify your ovulation window:

Monitor cervical mucus changes

Before ovulation, your cervical mucus can be yellow, white or cloudy in color, and gluey or stretchy in consistency. But as you approach ovulation, you may find that your mucus has become more clear, watery and slippery. For many, the consistency can remind them of egg whites.

That clear, slippery mucus will stay during ovulation. This is your body’s way of helping sperm reach the uterus. The amount of cervical mucus may increase as well.

Record your basal body temperature

Your basal body temperature (BBT) is your body’s resting temperature. And tracking your BBT daily for a couple of months may help you predict when you’ll ovulate.

Just before ovulation, your BBT may decrease slightly. After ovulation, it may increase slightly – typically less than a half degree Fahrenheit – and stay elevated for a few days. If you’ve conceived, your BBT may stay elevated for the remainder of your pregnancy.

The best time to check your BBT is right after waking up in the morning – before any other activity such as getting out of bed, eating, drinking or going to the bathroom.

To ensure the most accurate results, use the same method each time and try to take your temperature at the same time each day. Results can also be affected by how long you sleep each night.

Use an ovulation testing kit

Ovulation testing kits (or ovulation predictor kits) can help detect a surge in the luteinizing hormone (LH) levels in your urine. LH is what tells your ovary to release an egg during ovulation.

An LH surge can happen anywhere between 16 and 48 hours before ovulation. So, pinpointing a surge in the hormone can help tell you when you’re about to ovulate. And knowing this can help you time sex with your partner and increase your odds of conceiving.

Some examples of ovulation testing kits include:

  • Easy@Home Ovulation Test Kit
  • Pregmate 50 Ovulation Test Strip Predictor Kit
  • First Response Daily Digital Ovulation Test
  • Clearblue Digital Ovulation Test
When do you start testing for ovulation?

All ovulation testing kits come with instructions, but typically you start testing at the beginning of your fertile window. This is usually about three to five days before you expect to ovulate.

You’ll test yourself at least once a day at the same time (usually in the afternoon) until you get a positive or “peak” result. Record your test results using your journal or fertility app. Or if the testing kit you’re using offers an app, you can use that as well.

Blood tests to detect ovulation

Progesterone levels also increase during ovulation. A simple blood test can determine your progesterone levels on the day of the test. Tests are usually done on a specific day during your cycle to confirm if ovulation is occurring or has occurred.

Blood tests for progesterone and other hormone levels are often used for those experiencing signs of infertility.

Talk to your doctor about follicular monitoring

Follicular monitoring uses ultrasound scans to track the development of ovarian follicles, small sacs in the ovaries that grow and release eggs. Follicular monitoring can help with conception by identifying when an egg is about to be released, or it can help diagnose follicle-related fertility issues.

Follicular monitoring is frequently used as a part of infertility treatment, particularly for those pursuing in vitro fertilization (IVF).

Bringing it all together: Timing sex during your fertile window

Tracking your cycle and patterns helps you understand your body better and identify when your fertile window should occur. Then with the help of ovulation prediction methods, you can narrow down your ovulation window during your fertile window. The next step is putting it all together to time sex with your partner.

You’ll want to take advantage of your entire fertile window to maximize your odds of conception, but pay special attention to your ovulation window. Remember, sperm can live in your reproductive tract for up to five days.

This can mean having sex every day or every other day during your fertile window to make sure sperm is there to meet the egg when it’s released.

Got questions about fertility or ovulation? We’re here for you.

If you’re trying to get pregnant, understanding your fertility is the first step in increasing your chances of doing so. And while there are things you can do at home, you don’t have to do it all on your own.

If you have any questions or concerns, talk with a doctor or clinician. You can start with a primary care provider, such as a family doctor, physician assistant or nurse practitioner. If needed, they can connect you with a specialist. Or, you can make an appointment directly with an OB-GYN or midwife, both of which are experts in female reproductive health.

How many days after your period are you least fertile?

As a result, there are around 21 days in the menstrual cycle on which pregnancy is less likely. The days before and during menstruation are the least fertile days of the menstrual cycle. People with a menstrual cycle that is shorter than 28 days could ovulate within days of their period ending.

Are you fertile right before your period?

Although it is possible to get pregnant in the days leading up to your period, it isn't likely. You can only get pregnant during a narrow window of five to six days a month. When these fertile days actually occur depends on when you ovulate, or release an egg from your ovary.