Chart Variations

Lesson 15

Lesson Objectives:

  • To become familiar with a variety of "non-ideal" fertility chart patterns.

Major Points in this Lesson:

  • It is not unusual to have a chart that does not match the regular/ideal pattern. A chart can still be very "normal" and not fit the ideal.

  • Some women will only occasionally have an unusual cycle, while others will rarely see an ideal chart pattern.

  • A bit of extra flexibility is required to interpret charts that do not have "textbook" patterns but it is usually still possible to identify the ovulation date and analyze a chart that does not match the ideal.

  • Charting multiple signs helps to interpret ambiguous signs because you can "cross-check".

  • There are a number of ways that your chart may differ from the ideal pattern. The most common variations from the ideal are: a slow rise temperature shift pattern, a fallback rise pattern, non-correlated signs, an ambiguous thermal shift and erratic temperatures


This lesson will describe the ways in which your chart may differ from the ideal. Your next lesson will illustrate further with example charts.

Common Chart Patterns (Variations)

In many cases, one or more elements of the regular (ideal) ovulation pattern will not be present, will be present in a different variation, or the signs will not perfectly correlate. This is usually not a cause for concern. Your fertile time and your day of ovulation can still be determined by careful analysis- even under less than ideal circumstances.

The pattern may be skewed because of non-ideal data collection methods, problems with manufactured devices or being unable to follow the manufacturer's instructions precisely. Temperatures taken at different times or without enough sleep can alter the pattern, as can the subjective nature of cervical fluid and cervical position observations. Stress, fatigue, travel and illness can also impact your chart.

Additionally, your own unique fertility pattern may not exactly match the ideal. This is the human element of fertility charting and this is just part of charting while living your life. Unless you are not following the basic guidelines of charting, this is largely unavoidable. As you gain experience your chart will also become more reliable. Fortunately, you can usually see your fertility pattern even when your chart does not match the ideal. You can still identify your fertile phase and detect ovulation with a variant of the ideal ovulation pattern.

Here are some ways your chart and your pattern may differ from the ideal and still show ovulation:

  • Slow/Sloping Rise

  • Fallback Rise

  • Sawtooth Rise

  • Staircase Rise

  • Erratic temperatures

  • Out of place temperatures

  • High temperatures during period

  • Erratic temperatures during period

  • Dip Before Rise /Ovulation Dip

  • Multiple patches of fertile cervical fluid

  • Multiple positive OPKs or Positive OPK several days before Ovulation

  • No egg white cervical fluid/No egg white cervical fluid before thermal shift

  • Microscope, OPK, or Fertility Monitor does not correlate

  • Fertile cervical fluid after ovulation

  • Cervical position or cervical fluid does not correlate with temperature signs

  • Temperature shift may be ambiguous

Slow or Sloping Rise

Temperatures may rise in a sloping rise rather than an abrupt shift. The rise may be gentle and curved and may take three to four days to reach the elevated level that clearly shows that ovulation has occurred. A slow rise may show a steady shift in small increments of one tenth of a degree Fahrenheit over four or five days.

Fallback Rise

Temperatures may show a "fallback rise" pattern. In a fallback rise pattern the temperature rises significantly and abruptly as you would expect, but then it drops again immediately before it rises again and is sustained throughout the luteal phase. You may not be able to tell whether you are seeing a fallback rise pattern or whether you are seeing one "fluke" high temperature. Your non-temperature signs, or, retrospectively, your luteal phase length, can help you to determine whether or not you have a fallback rise pattern.

Sawtooth Rise

Temperatures may rise in a "sawtooth" rise pattern. In a sawtooth rise pattern, the temperatures may rise, fall slightly, then rise again for a few days. This is a frequently occurring pattern.

Staircase Rise

In a staircase pattern, the temperature will rise, stay steady or even slightly decrease and then rise and stay steady again until reaching the elevated level. This may occur over a period of a few days.

Long Cycles

Your chart may show increased fertility and ovulation later in your cycle. Often charts with long cycles show signs of increased fertility, such as multiple patches of fertile cervical fluid, more than once before ovulation actually takes place. This may be a usual pattern for you, or, you may from time to time have a cycle with later ovulation. Long cycles can be particularly frustrating when you are trying to conceive because you need to keep on scheduling intercourse until ovulation is confirmed by a sustained thermal shift. It's not unusual to get very impatient or "burn-out" from frequent lovemaking as you wait for the shift.

Erratic temperatures

Even if your temperatures are erratic, going up and down throughout your cycle, and not showing a single sustained shift between pre- and post-ovulation phases, they may still indicate ovulation, especially if there are other signs that can be correlated.

Out of place temperatures

Both in your pre-ovulation phase and your luteal phase, you may have temperatures that just do not seem to "fit". This is usually nothing to worry about since you are looking for trends over time rather than individual temperatures. Seemingly out of place temperatures can be a fluke or can be caused by any number of factors. A few out of place temperatures can usually be ignored without impacting the interpretation of your chart, especially if they are not close to ovulation. There is generally no need to discard out of place temeratures.'s automatic ovulation detector is able to detect ovulation based on the pattern of your chart and all signs, even when some data is not accurate.

High temperatures during period

It is not unusual to have high temperatures during your period due to residual progesterone from your previous cycle. They will usually level off in time to recognize a thermal shift in your current cycle.

Erratic temperatures during period

It is not unusual to have erratic, high and low, temperatures during your period. Usually they will level off in time to recognize a thermal shift in the current cycle.

Dip Before Rise /Ovulation Dip

As estrogen increases before ovulation, you may see a slight temperature dip, sometimes called an "ovulation dip" before your temperature rise. If you are lucky enough to get advanced warning of ovulation like this over several cycles, this can be a good sign to help time intercourse very close to ovulation. You may, however have a dip that is not followed by a sustained rise and mistakenly assume ovulation is imminent when you see the dip. Keep in mind that an individual dip on its own does not tell you anything about ovulation or your fertility. Make sure to wait for the temperature rise before assuming that ovulation has passed.

Multiple patches of fertile cervical fluid

You may get more than one patch of fertile cervical fluid in a given cycle. Though you will only ovulate once, usually just after the last patch of fertile cervical fluid, you need to treat any fertile-like cervical fluid as potentially fertile so you do not miss a chance for conception. If your temperature pattern is very clear and shows that ovulation has passed, you can probably ignore a patch of fertile quality cervical fluid in the luteal phase without hurting your chances.

Multiple positive OPKs or Positive OPK several days before Ovulation

Luteinizing Hormone (LH), which is detected by Ovulation Prediction Kits, may be elevated even when you are not immediately approaching ovulation. This can cause you to see multiple positive OPKs. When this happens, you will probably ovulate just after the last positive OPK if you continue to use the kit, though this may occur in anovulatory cycles as well. Nonetheless, you should treat any positive OPK reading as meaning that you may be about to ovulate.

Some fertility medications may interfere with OPK results. Check with your doctor and/or the OPK manufacturer if you are taking fertility medications and observe unusual OPK results.

No egg white cervical fluid/No egg white cervical fluid before thermal shift

You may not get a patch of fertile cervical fluid just before your thermal shift, even though the shift indicates that you ovulated. If this is a frequent pattern for you, you should try to time intercourse as close to ovulation as possible and treat the cervical fluid that you get closest to ovulation as your most fertile cervical fluid. The vertical line indicating your ovulation day appears dotted when there is no fertile cervical fluid observed around ovulation time. This indicates that the ovulation date is not certain and is meant to alert you to keep on the lookout for fertile signs so you do not miss a chance to conceive.

Microscope, OPK, or Fertility Monitor does not correlate

Sometimes the devices that you can purchase for monitoring your fertility do not agree with your other charting data. In most cases, your temperature data is best able to pinpoint and confirm ovulation since it is the sign that shows you that that ovulation has passed. The tests and devices are useful for indicating increased fertility before ovulation. It is possible to ovulate without any commercial device that you may be using showing you signs of increased fertility. It is thus recommended to pay close attention to other signs and keep having intercourse until ovulation is confirmed by a thermal shift.

Fertile cervical fluid after ovulation

While cervical fluid typically dries up immediately after ovulation, it is sometimes present even after ovulation. This is because the corpus luteum produces some estrogen at this time and this may cause you to see some cervical fluid. If you have already ovulated and temperatures are clearly elevated and the elevation is sustained, this need not be treated as fertile fluid and the ovulation date does not need to be put in question. If the thermal shift is not dramatic, however, you may want to consider that you could still be fertile if you observe fertile cervical fluid later in the cycle, just to make sure you do not miss a chance to conceive.

The vertical line indicating ovulation is dotted when seemingly fertile cervical fluid is observed at this time. This is meant to alert you to keep observing your signs and to consider yourself as potentially fertile if ovulation has not certainly already passed.

Cervical position or cervical fluid does not correlate with temperature signs

Your cervical position or cervical fluid may not correlate with your temperature or other data when they are cross-checked. will offer the most probable assessment of your fertility and ovulation date based on the data available.

Temperature shift may be ambiguous

In some cases it will be clear that ovulation occurred but it will not be possible to pinpoint the date definitively with certainty. In such cases the temperature may rise very slowly, have some dips, or some data may be missing or conflicting in such a way that makes it impossible to tell exactly when ovulation happened.

Though it is frustrating when you cannot pinpoint ovulation with certainty, keep in mind that the most important thing is not to have a perfect chart, but rather to make sure you have had intercourse in your fertile window. When you have an ambiguous chart, it is recommended to consider the latest possible ovulation date to help avoid testing too early. Then, if you turn out not to be pregnant that cycle, you can go back and adjust your chart using your luteal phase length as a guide.

When your chart pattern is not "ideal"

Your own ovulation pattern may include one or more of the above special circumstances. There are a variety of "normal" ovulation patterns and ovulation can usually be detected and your chart can usually be interpreted even when your chart is not "ideal".

An ambiguous fertility chart can be frustrating, especially while trying to conceive. You want to know exactly when ovulation has passed and you want to know the earliest date to take a pregnancy test. Keep in mind, however, that having a beautiful, perfect fertility chart is not the most important thing when you are trying to conceive. Having a clear chart is great, but most importantly, you are trying to maximize your conception odds and your chart is a tool to help you do so. If you get an ambiguous chart while trying to conceive, maximize your conception chances by continuing to consider that you could be fertile any time that you see fertile signs or if ovulation has not already clearly passed.

Next Lesson: Chart Variations: Illustrations

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