Fertility Charting

Fertility charting is performed to monitor and check a woman's fertility during her monthly cycle. Charting fertility signs can be helpful in diagnosing and resolving fertility issues such as problems with ovulation. There are three steps involved when charting:  1) Checking your basal body temperature (temperature upon waking) every day 2) Checking your cervical mucus and 3) Checking the position of your cervix.

Fertility charting can help you to:

• See if and when you ovulate

• Calculate your cycle length

• Determine the length of the follicular and luteal phases

• Make love during your most fertile time

• Achieve pregnancy more quickly

• Diagnose your pregnancy early

• Evaluate your cycle for possible fertility problems

• Assess other fertility signs like cervical position and cervical mucus

• Assess the effects of fertility medications

One of the most important elements in charting is to identify the days during your cycle that you are most fertile so you may be sure to have intercourse on those days to increase your chances of conception.

Before ovulation, a woman's basal body temperature (BBT) generally ranges from 97.5 to 98.2 degrees Fahrenheit on average, though it can vary occasionally and be higher or lower. When ovulating, the ovary releases progesterone, a warmth inducing hormone. Generally, a woman’s temperature will not change more than 0.5 degrees during the follicular phase, it will go up at least 0.2 degrees at ovulation and it will stay above the coverline (line drawn at temperature increase for ovulation) during the luteal phase. Within days of menstruation the temperature usually decreases to pre-ovulation levels. Pregnancy causes a woman's BBT to remain elevated beyond the 14 days after ovulation, therefore experiencing higher temperatures past the expected date of menstruation can be the first symptom of pregnancy. 

Charting your BBT diagnoses ovulation only after it has happened so you should also look for other fertility signs, such as checking the cervix or the cervical fluid, if you want to predict impending ovulation. Cervical mucus changes several days before ovulation by becoming more abundant and stretchy, and the position of the cervix changes as well. Within 1-2 days after ovulation these typical changes disappear, so also charting these indicators will not only help you determine if you are ovulating properly, but will help you predict when ovulation will occur.

Remember, having intercourse after ovulation has occurred is too late to achieve conception. Your peak day is usually the day before or the day of ovulation. Charting your fertility signs as described below will help you to determine your most fertile days, the optimal days for conceiving.

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Charting Basics

Download our free fertility charting calendar here and start keeping track of your waking temperature on the first day of your menstrual period (first day you see red blood).  The chart is in PDF format so you'll need the free Acrobat Reader to view it.

For best results, use a basal body thermometer that shows precise changes of 1/10 of a degree in your temperature. Special BBT thermometers are usually more reliable and more accurate and they come in both standard mercury and digital models.  Other types of glass or digital thermometers will also work but they generally measure only 1/100 degree changes. If purchasing a new one, we recommend a digital BBT style since they only take 30-60 seconds to get a reading and most will remember the temperature for you if you don’t get to chart it immediately.

You may take your temperature in the mouth, the rectum or even the vagina, but you should always take your temperature in the same place each day for more consistent results.

Your basal body temperature should be taken before you get out of bed, but after at least 3-4 hours of continuous sleep and preferably at the same time each day.  Note the time of day you took your temperature, as well as the temperature itself, on your chart.  You should not eat, drink, or even get up to urinate before taking your temperature.  Start taking your temps on the first day of your cycle, the day you begin your menstrual period.

Your temperature reading can rise up to 1/10 of a degree for every half an hour taken later than normal or fall 1/10 of a degree for every half hour taken earlier than normal. For best results, try to take your temperature as close as possible to the same time everyday, however if you sleep in on the weekends just remember that each temperature that is not taken at the normal time will be slightly different.  We DO NOT recommend that you adjust your temperatures, but you should always log the time your temperature was taken each day so you'll be able to determine if waking time is the reason for any rise or decline in your temperature reading.

Circle the appropriate temperature reading each day on the chart you downloaded, along with any other indicators. If you miss a day of charting, or didn't get enough sleep to take a temperature reading, just skip that day (leave it blank) and move on to the next.  Draw a line connecting each day's temperature reading to the next day, a dashed line to denote any skipped days, so that you can visualize your temperature curve.

Sometimes, but not always, you will see a drop in temperature on the day of ovulation.  Usually you will see an increase in your waking temperature by at least 0.2 degrees 1-2 days after you have ovulated.

Drawing a coverline is a very important step in charting as it is drawn to help you distinguish when you have ovulated. Calculate your coverline after your temperatures show that you have ovulated - identify a temperature that is at least 0.2 or 2/10's of a degree higher than the previous 6 days. Find the highest temperature of those six days and draw a straight line that is 0.1 or 1/10's of a degree higher than that of the highest temperature. This line is your coverline and it should run straight across your chart horizontally.  Illness, lack of sleep or stress can adversely affect your baseline temperatures and cause a higher temperature reading than ordinary. You should overlook these temperatures when calculating your coverline.

In a typical biphasic chart, the temperatures will increase 1-2 days after ovulation and then stay above the coverline until your next menstrual period. The first phase (before ovulation) is called the follicular phase, and the second phase is known as the luteal phase, where temperatures rise because of increased progesterone production. Temperatures typically drop a day or two after your menstrual period comes, but can sometimes drop a couple of days before it.

In a triphasic chart the temperature curve shows another rise, often within 7-10 days after ovulation, for three distinct phases on the chart. 

Once your menstrual period begins you should indicate in the "Period" row on your chart at the end of your cycle that bleeding has started with a "B". Days where you only experience spotting should be marked with an "S".  Be sure to indicate the first day of bleeding as the first day of a new chart and the last day of the previous chart. This allows you to calculate the cycle length and the luteal phase (time between ovulation and next menstrual period). 

If your menstrual period has not started and your waking temperature stays up longer than 15 days, that's a good early indication that you may be pregnant. The luteal phase is usually the same length every month. After ovulation has occurred you can indicate a pregnancy by watching for the passing of your normal luteal phase. For example if you always have 14 days between ovulation and when your period comes and its now day 16, there is a very good chance you are pregnant. If you've had 18 days of high temps then odds are very high that you have conceived.

When you determine that you are pregnant, either through a positive urine or blood pregnancy test, you can stop taking your temperature. Taking your temperature during pregnancy can be very confusing and won't tell you much about the viability of the pregnancy. The BBT chart is done mainly to check if and when you ovulate, and when to perform a pregnancy test. 

If you are taking fertility medications, your temperature charting may not be as accurate as it would normally be, but you should continue to take your temperature as your chart can still help to interpret what is happening with your cycle. Keep in mind that Clomid can cause elevated temperatures while taking the medication and it can cause a longer luteal phase. 

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Cervical Mucus

Cervical mucus is produced by the cervix and its consistency changes throughout your menstrual cycle based on hormones associated with ovulation. After the menstrual period ends, cervical mucus is dry and prevents sperm from penetrating the cervix. Approximately a week before ovulation estrogen levels cause the cervical mucus to become abundant, sticky and thick, which helps the sperm to penetrate the cervix. The following chart shows typical changes in cervical mucus throughout the menstrual cycle ( based on a 28-day cycle):

Cervical fluid is an essential element to conception due to its ability to keep sperm alive for up to four days (in fertile quality fluid) as it protects the sperm from the acidity in the vagina and transports it to the outer third wall of the fallopian tube where fertilization takes place. Therefore, your chances of pregnancy are greatly increased with intercourse right before ovulation because the sperm can live for about 3-4 days, an egg is present for about one day, and the cervical mucus is the most "friendly" for sperm at this time.

Fertile cervical mucus should be abundant and feel wet for two to four days before ovulation. It can appear either thick and creamy or like hand lotion and will form peaks in your fingertips when pulled apart or can be thinner and look milky. The color of the fluid is white or yellow and the overall vaginal sensation is wet. If you do not produce egg white cervical mucus, the last day of either milky, creamy or lotion like fluid would be considered your peak day.

Egg white cervical mucus is present during the most fertile stage which lasts for one to five days.  This mucus will look like and have the consistency of egg whites. It is slippery to the touch and if pulled between the fingertips can stretch from one to ten inches! The color can be clear or iridescent and the overall sensation is extremely wet.

Egg white cervical mucus, or "spinnbarkeit" mucus, is usually a sign of an increase in the estrogen hormone. This generally happens around the time of ovulation, but ovulation doesn't necessarily occur just because there is egg white mucus, so you can get egg white fluid and not ovulate. The typical biphasic BBT curve is an indicator of ovulation however, so if your chart shows two distinct phases you will know that you have ovulated. Having a biphasic BBT curve is a much better indicator of ovulation than egg white cervical mucus. 

You should start checking your cervical fluid on the first day after your menstrual period, and check it several times during the day. You should also try to be aware of the overall vaginal sensation (wet or dry) you have throughout the day without physically checking.

Be sure to start with clean hands. Separate your vaginal lips with one hand and slip the middle finger of the other hand inside the vagina and locate your cervix. Press your finger against the sides of the cervix applying a small amount of pressure - make sure your nails aren't rough and that they are clean. Draw your finger out of the vagina slowly and inspect the fluid.

Rub your middle finger and thumb together to determine if the mucus feels dry or wet, thick or thin, sticky or creamy, or slippery like egg whites. When you pull apart your middle finger and thumb, does the fluid stretch? Does it crumble or gum up? Does the fluid remain on your fingers or does is dry up quickly? What color is it - clear, white or yellow?  Note your findings on your chart.

You should also take notice of any fluid stains left on your underwear. When you are extremely fertile the cervical mucus is abundant and has a high water content which will leave a fluid stain in the form of a circle. Less abundant non-fertile mucus is dryer and tends to form more of a rectangular shape.

Don't be scared or nervous about checking your cervical mucus, once you've done it a few times you'll find that it is very easy and only takes a few extra seconds. The information you will gain is well worth the effort to help you conceive.

Since your temperature readings will rise only after ovulation has taken place, charting temps alone without using cervical fluid and position will not indicate when your most fertile time is until after ovulation has occurred - which is too late to conceive. Therefore, we recommend that you chart all indicators to get a more efficient reading of your most fertile times.

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Cervical Position

A combination of charting your waking temperature, your cervical mucus and your cervical position will indicate when your most fertile time is. 

During your most fertile time, your cervical position rises within your body, your cervix gets soft and the slit becomes open. 

Start checking your cervical position after your menstrual period ends. The position of your cervix will be low within your body and easily reached with your fingertips at this time. The opening to your cervix will be closed and should feel like a small slit or a tiny hole, it will also feel rather hard to the touch. As with checking your cervical fluid, insure that your hands are clean and fingernails are not rough.

With one hand holding back the vaginal lips insert the middle finger of the other hand into your vagina. Move your finger up slowly until you hit your cervix. It should feel like a rounded cylinder shaped mass within your body.

The estrogen increase a day or two before ovulation occurs causes your cervix to rise. You will find when checking your cervical position on a daily basis, that it will move from the lowest point to the middle and then to a high point. At the highest point it may be difficult to reach your cervix with your fingertips. The opening of your cervix increases as well, which makes the slit or tiny hole feel much larger. The cervix will also feel much softer now. These are indications of your peak or most fertile time. The cervix will remain high and soft until you ovulate - after which estrogen subsides and the hormone progesterone is released, which causes your cervix to return to its low, closed and hard position.

You may check your cervical position while sitting on the toilet, squatting on the floor, or with one foot on the bathtub or toilet seat. Choose a position you are most comfortable with and use the same position consistently throughout your cycle. 

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Possible Issues

Charting can help to identify many fertility issues, such as anovulation, low estrogen levels, low progesterone levels, and possible miscarriages.

An anovulatory cycle is a cycle in which ovulation did not occur and it can be identified by charting your waking temperatures. When viewing charted temperatures that have many low and high temps throughout the cycle with no clear separation of a rise from the first phase (pre-ovulation) to the second phase (luteal phase), this is a good indication that ovulation did not occur. Many women who are able to conceive can have an occasional month where no ovulation takes place - however, since this can be an indication of other issues, we recommend that an anovulatory cycle should be followed by a visit to a medical professional for further testing.

Estrogen plays a large part in the ability to conceive as it is the hormone needed for ovulation. Estrogen is produced by the follicles that hold the eggs and it plays a part in determining the amount and quality of cervical mucus that is crucial for the sperm to travel up to the fallopian tubes for conception. An anovulatory cycle along with a low amount or poor quality cervical mucus can be an indication of low levels of estrogen. 

Progesterone is another important hormone within the cycle which is produced by the corpus luteum during the luteal phase. When an egg is released the follicle that held it collapses and becomes a yellow bodied mass called the corpus luteum. The corpus luteum sticks to the ovarian wall and produces progesterone for its life span of about 12 to 15 days. Progesterone ensures that all maturing eggs (15 - 20 within a cycle) are not released, it thickens the uterine lining, and causes some signs of fertility - egg white cervical mucus, and high cervical position to return to a non- fertile state.

Low progesterone levels can be indicated by seeing temperatures close to, on or below the coverline after ovulation through the end of a cycle, or by a shortened luteal phase of less than ten days. Even if ovulation was achieved, low progesterone levels can make it very difficult to obtain a successful conception. Low progesterone levels can be treated in a number of ways, including progesterone shots, pills and suppositories, therefore we highly recommend a visit to a medical professional if your charts indicate low progesterone levels.

As heartbreaking as miscarriages are, they are unfortunately not a rare occurrence - as many as 1 out of 3 pregnancies end in miscarriage. Many miscarriages happen very early so if you were not charting you may confuse it with a late period and never realize that it had occurred. Passing the usual number of days in your luteal phase before a sudden drop in temperatures and bleeding may indicate that a miscarriage has occurred.  Contact a medical professional if you suspect that you are miscarrying.

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