Fertile Window Calculator: A Guide to Knowing Your Most Fertile Days

Have you decided it’s time? Thinking about adding a new member to your family? If you want to start conceiving, one of the first questions you will probably ask is, “How do I easily get pregnant?” The answer to that lies in knowing your most fertile days during your menstrual cycle.

At a Glance

  • Knowing your fertile days or fertile window is an essential tool you can utilize if you are trying to conceive.
  • Your fertile days (or fertile window) are the times of the cycle when a pregnancy can be possible. This window starts 5 days leading up to your ovulation. It then closes once your ovaries have released an egg into the fallopian tube, where it waits to be fertilized.
  • For women with a 28-day menstrual cycle, ovulation normally occurs on the 14th. Your most fertile days are likely on the 12th, 13th, and 14th.
    If your cycles are longer (35 days, for example), ovulation may occur on the 21st. Your most fertile days are on the 19th, 20th, and 21st.
    If your cycles are shorter than average (21 days), ovulation should happen around the 7th. Your most fertile days are on the 5th, 6th, and 7th.
  • Paying attention to your body and the way it changes throughout your menstrual cycle is also a good way of knowing your fertile days.
For some women, getting pregnant is no easy feat. If you are serious about wanting to conceive, then you must familiarize yourself with one thing: calculating your fertile days. At the end of this guide, you will finally learn how to determine your fertile window in order to maximize your chance at conception.

Fertile Days Calculator

What Are Fertile Days?

To put it simply, the matter of conceiving is all about proper timing. A woman can only become pregnant if she is ovulating. Your fertile days (or fertile window) are the times of the cycle when a pregnancy can be possible. It is the window when you ovulate and the 5 days leading up to it. This window starts 5 days leading up to your ovulation. It then closes once your ovaries have released an egg into the fallopian tube, where it waits to be fertilized.

FAQ: “Can I recognize my fertile days?” – No. It is impossible without special tests or exams. The closest thing you can get to recognizing your fertile days is through approximated days using your menstrual cycle.

How Does Pregnancy Happen?

In order for conception to happen, sperm must unite with the egg in the fallopian tube. In hindsight, the ovulation itself is the most important date during your fertile window. During ovulation, an egg is released into the fallopian tube. Once it is released, the egg only has a lifespan of about 12 to 24 hours for it to be viable for fertilization [Source: Women’s Health]. When it is not fertilized, it degenerates and triggers your next period.

Sounds simple so far? Here is where it gets complicated. In a 28-day cycle, ovulation happens between the 13th and 17th day. However, only very few women have consistent cycle lengths. Every woman is different. This makes it impossible to accurately determine the start of ovulation.

Factors like stress or malnutrition, the length, and consistency of a woman’s cycle can also matter when determining your fertile window. Since there are many factors to consider, we need to look beyond observing your period to have a deeper understanding of when ovulation occurs.

FAQ:What is ovulation?” Basically, it is when a mature egg is released from the ovary and down to the Fallopian tube to await a sperm for fertilization.

Woman thining about her fertile days

When Does Pregnancy Become Possible?

When the luteal phase (or post-ovulation) starts, eggs are viable for a short 12 to 24 hours. Sperm, on the other hand, can live up to 5 days. All in all, fertile days happen for about 6 days, from the day of the ovulation and the 5 days before it.

Even though your egg has a lifespan of 24 hours, a sperm can survive and fertilize it for up to 5 days after intercourse. This means that any intercourse within 5 days of ovulation can result in conception [Source: American College of Obstetricians and Gynecologists]. Note that the closer to ovulation your intercourse is, the bigger your chances are of getting pregnant.

Average Cycle

There is absolutely no “average” or “normal” cycle. Every woman has a unique and individual cycle that may even fluctuate each month. They can also vary throughout one’s life.

As mentioned above, every woman’s cycles vary. However, here are what happens on an average 28-day cycle, when your body prepares for a possible conception.

Day  
1-5• If not pregnant, dead tissue lining the uterus disintegrates marking the start of menstrual cycle.
• Low progesterone and estrogen levels.
• Body temperature: 96 to 98 F
6 - 7• Gonadrotopin (GnRH), Follicle stimulating (FSH) and luteinizing (LH) hormones are released, which causes the egg to grow.
• As the eggs grow, estrogen levels increase.
• Cervical mucus is dry.
8• Due to estrogen increase, uterus lining becomes thicker and generates richer supply of blood vessels in preparation to receive the fertilized egg.
10• Mucus becomes wet and produces cloudy, sticky, yellowish or white discharge.
12• Mucus becomes clear and stretchy. This signals the start of the ovulation.
• You will have the maximum chances of conception during this time.
13• Exaggerated rise in estrogen and body temperature.
14• Estrogen levels drop significantly, which causes the ovary to release the egg – ovulation.
• The egg is fertile for 12-18 hours.
15• The empty egg follicle produces more estrogen and progesterone to help prepare for possible pregnancy.
17• If your body temperature has been high for 3 days, it may mean your fertile window has ended.
18• Mucus becomes cloudy.
21 - 22• Peak levels of progesterone.
25• Corpus Luteum breaks apart.
• If pregnant, progesterone drops and mucus becomes tack.
• If pregnant, progesterone level is high.
27• Mucus is absent.
28• Decrease in progesterone and estrogen levels.
• If not pregnant, you period will start the next day.
Worried about irregular cycles? Stop. They are actually considered normal.
  • For 28-days, ovulation normally occurs on the 14th. Your most fertile days are likely on the 12th, 13th, and 14th.
  • If your cycles are longer (35 days, for example), ovulation may occur on the 21st. Your most fertile days are on the 19th, 20th, and 21st.
  • If your cycles are shorter than average (21 days), ovulation should happen around the 7th. Your most fertile days are on the 5th, 6th, and 7th.

Your Menstrual Cycle

The first 5 days of your period are considered your infertile days. However, this is only true if you do not use the pill, which is a hormonal influencer. After your menstruation, particularly from the 6th day of your cycle, conception is theoretically possible.

Since it is difficult to determine fertile days for every woman, it is helpful to observe your bodily changes instead. This can be done by your physician or by training yourself to recognize the signs.

False Information and Myths about the Fertile Window

You would think that, with the current technology and easy access to information, false facts will no longer be so widespread. Surprisingly enough, there are still books and brochures today that contain misleading information about fertility.

Here are some facts you need to steer clear from:

  • It is best to try conception exactly halfway between two menstrual cycles.
  • You are most fertile during the middle of the average cycle.
  • Sperm can only last up to 3 days at most.
  • It is safe not to use contraception until day 7 of your cycle.
  • The average cycle is 28 days long.
  • It is impossible to conceive during menstruation.
  • Days 7 to 9 (after menstruation) are safe from possible conception.
  • It is impossible to get pregnant after ovulation (takes place no later than Day 18 of the cycle).
  • It is 100% safe during the week before menstruation (days 22 to 28 of the cycle).
MYTH: The most fertile day is during the 14th day of your menstrual cycle. BUSTED: The time when women are able to conceive is during the fertile window. The fertile window varies cycle to cycle. However, having intercourse at the right time (6 days leading up to and including ovulation) is when the chances of conception are highest.

Additional Tips to Get Pregnant

Now that you have taken the first step towards a successful conception (calculating your fertile days), here are a few more helpful tips to increase your chances of getting pregnant even more!

  1. Utilize your fertile window. Obviously, you now know which days you are able to conceive, so make sure you and your partner keep this in mind and start working on it. Having sex at the right time is the main goal of getting pregnant.
  2. See your doctor. Seeking advice from a professional may be your best weapon going forward when it comes to getting pregnant. Making sure that you are fully prepared, physically and mentally,  will only improve your chances of conceiving. What are you waiting for? Schedule a preconception checkup now!
  3. Prepare your body for pregnancy. Don’t they say that preparation is the key to success? Make sure you start taking care of your body in anticipation of carrying your baby. Start taking folic acid one month before you try conceiving. Get rid of any unhealthy habits like drinking, smoking, and taking drugs. Avoid drinking coffee.
  4. Boost your partner’s sperm. You shouldn’t do all the work! A strong and healthy sperm can fertilize an egg the best. A few tips to improve sperm health include skipping harmful substances like tobacco and recreational drugs, minimizing alcoholic intake, and following a healthy diet rich in vitamin C, folic acid, and zinc. Avoid using hot baths, showers or saunas because it has been proven that heat can kill sperm.

When to Consider Getting Help

Getting pregnant can be a lot harder for others. Certain factors may cause the struggle or inability to conceive. However, if you just started trying, there is no cause for worry just yet. Getting pregnant may take time, and you need to be patient. However, you should start considering getting professional help if:

  • You are below 35 and have been trying to conceive for a year without any success;
  • You are above 35 and have been trying to conceive for 6 months without success;
  • Either you or your partner may have risk factors, or if you are experiencing symptoms of infertility (e.g., endometriosis or PCOS for women);
  • Either you or your partner has a history of sexually transmitted diseases;
  • If you have a family history of conditions like primary ovarian insufficiency or early menopause; and
  • If you have experienced repeated miscarriages.

In Conclusion

Calculating your most fertile days is not an exact science. But it doesn’t mean there is no way of having an idea when it is the best time for you to try conceiving. Your main job when it comes to doing anything related to pregnancy and, later on, parenting is to always educate yourself so you can make informed decisions.

Remember:

  • For a more accurate fertile window, do not just settle on period count. Recognize your body’s signs.
  • Live healthily. Stress and other health factors may affect your chances of getting pregnant. Before you can take care of a little one inside of you, you need to prepare a healthy home for him or her as well.
  • Be educated. Research. Don’t be shy to ask questions.
  • See your healthcare provider. It is imperative that you avail of professional care for yourself as soon as you can to avoid unnecessary risk.
Fertile Window Calculator: A Guide to Knowing Your Most Fertile Days
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