Getting pregnant: When are you most fertile?

Defeated. Sad. Anxious. These are just a few of the many emotions you may feel after seeing yet another negative pregnancy test result.

Finding out you’re not expecting can be discouraging. There’s no need to give up on growing your family though! 

Determining your fertile windows can help you to increase your odds of becoming pregnant.

Knowing how to track your menstrual cycle and being aware of when you are most fertile is important information if you’re hoping to conceive. 

If you’re confused about how to do this or wondering if you’re doing it wrong, we’re here to clear up some common questions!

In order to calculate your fertility windows, it’s important to understand how your menstrual cycle and ovulation work.

How Menstrual Cycles Work

The menstrual cycle is a series of hormonal and physical changes that make pregnancy possible.

When the menstrual cycle begins the egg is in a fluid sac (called the follicle) in the ovaries. At the start of the menstrual cycle, several of these start to try to grow under the influence of the follicle stimulating hormone (FSH). For most women, only one of these will continue to mature and form the dominant follicle. This follicle produces estrogen to start preparing for ovulation or release of the egg.

After this follicle is mature, the Luteinizing Hormone (LH) surges. This causes the follicle to rupture and release the egg. Once the egg is released, it moves slowly towards the uterus through the fallopian tube. 

The egg can live for 24 hours. If you’re hoping to become pregnant, you’ll need it to come in contact with sperm during this time. 

Meanwhile, progesterone levels are increasing to create the appropriate environment for a fertilized egg.

If the egg is not fertilized, progesterone levels will drop causing the start of your period. This is marked by vaginal bleeding.

Learn More : What your progesterone levels means after ovulation

The “Average” Menstrual Cycle Length

Knowing the events involved in a menstrual cycle may leave you wondering how frequently one occurs.

It’s considered average to have a period every 28 days, but regular cycles that are longer or shorter than this (21 to 45 days) are still deemed normal.

Menstrual cycle

This means that if you had a period on July 1, it would be considered average to have another period around July 28 or 29
It would also be normal though to experience one as early as July 22 or late as August 14 depending on your typical menstrual patterns.
Why these differences in cycle length? Well, eggs differ in the amount of time they take to mature and release in each body.

Fertile Days In Your Menstrual Cycle

Sperm can survive in the female body for up to 5 days. Additionally, an egg has 24 hours to meet a sperm after it ovulates.

As a result, it is possible to get pregnant for 5 days before you ovulate and one day after. This 6-day window in the menstrual cycle is when you are most fertile.

Ovulation typically occurs 14 days before your next period. So:

  • If you have a 24-day cycle: your egg would be released on day 10. In this case, the fertile window would be from day 5 to day 11.
  • If you have a 40-day cycle: ovulation should occur around day 26. This would make the fertile window days 21 to 27.

It’s important to keep in mind that while ovulation occurs during most menstrual cycles, it’s normal to have a few anovulation cycles each year. (During an anovulatory cycle, an egg doesn’t mature, so fertilization can’t happen.)

Anovulation cycles can be caused by:

  • hormonal imbalance, 
  • chronic stress, 
  • weight fluctuations, 
  • intense exercise,
  • or an underlying disease. 

While occasional anovulatory cycles are normal, experiencing it chronically can prevent pregnancy.

Learn More: Anovulation: Everything you need to know about the #1 cause of infertility

Periods and Fertility

One common misconception is that women are most fertile the week before their period.

You’re actually most fertile at the time of ovulation, which typically occurs 12 to 14 days before your next period starts. 

Because menstrual cycle and ovulation schedules can vary, you’ll want to track your ovulation and not just your period if you’re trying to determine when you are most fertile.

Determining When (And If) You’re Ovulation

Up to 47% of cycles can vary by up to 7 days, so it can be tricky to determine when you are most fertile.

Some ways that you can determine when you are ovulating include:

  • monitoring cervical mucus
  • measuring basal body temperature
  • a pelvic ultrasound exam
  • the Inito Fertility Monitor
    Not all of these options are created equal, so it’s important to consider the benefits and drawbacks of each:
  • Cervical Mucus:
    Some individuals use changes in cervical mucus as a sign of ovulation. Generally cervical fluid is very light after the period. As your body moves towards ovulation, the cervical mucus becomes plentiful and stretchy like an egg white.

    If you use your fingers to gather some from the vaginal canal and stretch two fingers apart, the mucus can actually stretch up to a few inches when you are nearing ovulation.
    This can be very subjective to test for though. Also, there is a chance you may not experience this ovulation sign every month. 

Cervical Mucus
  • Basal Body Temperature (BBT): If you take your body temperature as soon as you wake up and while you are still in bed, it can help you to predict ovulation.

    A day after ovulation, the BBT rises, and it continues to rise until you get your period. This rise in the temperature is small (about 0.5 to one degree Fahrenheit).
    While this is less subjective than changes in cervical mucus, you may miss your fertile window, since the rise occurs only after you have ovulated.

Basal Body Temperature (BBT)
  • Pelvic Ultrasound Exam: The most accurate way to detect ovulation, during this procedure, a medical specialist will track the follicle growth over multiple ultrasounds to predict the ovulation day.

    The scan will also show whether the inner lining of the uterus, called the endometrium, is thick enough for a fertilized egg to stick to.
    While pelvic ultrasound exams can offer a lot of information, the procedure requires multiple visits to the doctor’s office, which can be inconvenient and costly.  

  • Ovulation Predictor Kits: There are a variety of ovulation testing kits you can purchase at your local drug store for home use. The testing strips inside can help you to identify when your estrogen is rising and you have an LH surge.

    Unfortunately, these tests won’t show that you have actually ovulated. You may be experiencing anovulation cycles and not know.
    The only way to know if you actually ovulated is via an ultrasound exam or a progesterone test. 

    The Inito Fertility Monitor is the only at-home testing option that tracks your FSH, estrogen, LH, and progesterone metabolite-PdG levels. 

    The Inito Fertility Monitor measures FSH, Estrogen, and LH in urine to suggest your fertile days. It confirms ovulation by measuring PdG – the urine metabolite of progesterone.

Maximizing Fertility And Increasing Your Chance Of Conception

There are many things you can do to increase your chances of a positive pregnancy test:
  • Make healthy lifestyle choices:
    A healthy lifestyle can increase your chances of becoming pregnant. Working with your doctor and other health professionals to achieve a balanced diet and the right amount of exercise can also help with your pregnancy.
  • Monitor the exact dates of a few cycles:
    Tracking your menstrual cycle can help you to understand the timing better. If you notice that your cycle is frequently irregular, you should talk to your doctor or a fertility counselor for guidance.
  • Get a physical and/or some blood work:
    It’s important to know what’s happening with your hormones if you’re hoping to become pregnant! Millions of women around the world struggle to become pregnant due to irregular menstrual cycles, PCOD, and hormonal issues.
    If you’ve been trying to become pregnant for many months, your doctor may suggest a variety of tests to ensure that there are no physical or hormonal barriers to pregnancy. 
  • Use an ovulation predictor kit to plan sexual intercourse:
    Having sexual intercourse when you are ovulating gives the best chance of conceiving. Using an ovulation predictor kit can make it easier to know the exact dates you’re ovulating. This way you won’t miss any potential days in your fertile window!

For example: 

The Inito App shows “high fertility” when Estrogen levels have risen. On high fertility days, it’s recommended that you have sex on every other day to maximize your chances of pregnancy.

The App will show “peak fertility” when your LH has surged. This means that you can expect to ovulate in the next 24-36 hours, and should plan to engage in sexual activity to increase your chances of pregnancy.

Following the LH surge, there should be a rise in Progesterone metabolite-PdG to show that you have actually ovulated. If you’re worried about whether or not ovulation happened, you can use the Inito Fertility Monitor to confirm.  It will show “ovulation confirmed” once your Progesterone metabolite-PdG has risen steadily after the LH surge.

One last thing to keep in mind: If you have a cycle when you don’t ovulate, just try again the next month.
However, if you have multiple anovulatory cycles you’ll want to check in with your doctor. (For more information about anovulation, check out [link to Inito Anovulation Blog Post].)

A Quick Look At When You Are Most Fertile:

  • Pregnancy can only occur for a certain window during the menstrual cycle.
  • The average menstrual cycle is 28 days, but regular cycles anywhere from 21 to 45 days are considered normal.
  • Ovulation typically occurs 12 to 14 days before your next period. However, the timing of individual ovulation cycles can vary.
  • Tracking your ovulation is key to knowing when you are most fertile.
  • You can increase your chances of becoming pregnant by having sex when you are most fertile.
  • Chances of getting pregnant are highest 5 days before ovulation and one day after.
  • You can gauge ovulation by cervical mucus, BBT, pelvic ultrasound exams, and ovulation predictor kits.
  • You can increase your chances of getting pregnant by living a healthy lifestyle, tracking your cycles, getting a physical/blood work, and using ovulation predictor kits.
  • Based on your FSH, Estrogen, LH, and Progesterone metabolite-PdG levels, Inito can tell you when you have “high fertility,” “peak fertility,” and “ovulation confirmed.”

Was this helpful?

The American College of Obstetricians and Gynecologists. (2015). Fertility awareness-based methods of family planning.

Su HW, et al. (2016). Detection of ovulation: A review of currently available methods.

Periods and fertility in the menstrual cycle.

Mayo Clinic. Menstrual cycle: what’s normal, what’s not.

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