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 female 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 menstrual cycle when your chances of conceiving a baby 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. After an egg is released, it moves down a fallopian tube to where it can be fertilized. Most often just one egg is released per cycle, but it’s possible for two or more to be released.

When do you ovulate after your period?

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 do you ovulate? Depending on your cycle, ovulation may occur between six and 20 days after your period starts.

However, if you’re using birth control methods like hormonal pills, rings, patches or some IUDs, it’s important to know that those help prevent pregnancy by preventing ovulation from occurring. But ovulation should resume shortly after stopping hormonal birth control. Barrier methods like condoms, diaphragms, cervical caps or spermicides do not impact fertility.

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 noticeable physical symptoms.

Ovulation symptoms to watch for
  • 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.

Calculating 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. This can also help you identify period irregularities.

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.

While all fertility-related tracking apps are a little different, all run on the personal information you enter. That information helps the app predict when you may start your next period or enter your fertile window, as well as help you understand the symptoms you might be experiencing.

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:

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.