As ovulation occurs, the increased production of progesterone generates greater heat in the body and the body-at-rest temperature rises. This is what you must measure to ascertain whether or not ovulation is over and when it occurred. A strong, immediate and sustained rise indicates healthy progesterone level.
If ovulation doesn't occur, then the temperature won't go up, and if menstruation doesn't occur, then the temperature won't come down.
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| Most Fertile Days |
Sloping Rise: Temperatures may rise in a slope 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.
Slow Rise: Similar to a sloping rise, but in even smaller increments, temperatures may rise in a slow rise pattern rather than an abrupt shift. The 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.
Staircase Rise: Temperatures may rise in a staircase rise pattern. 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.
Triphasic: It has been suggested that triphasic charts often turn out to show pregnancy, but just as often, they do not. A triphasic chart shows three levels of temperatures: pre-ovulation, post-ovulation, and then a second rise after ovulation.
Delayed Thermal Shift: Multiple patches indicating increased fertility within your cycle but the thermal shift and ovulation may occur later than expected in a cycle that is longer than usual. A cycle like this may show signs of increased fertility, (egg white cervical fluid, positive OPK, high, soft cervix, peak reading on fertility monitor, ferning on microscope devices) both just before the rise and earlier in the cycle when ovulation did not immediately follow.
Short Cycles (less than 25 days): Your chart may show increased fertility and ovulation earlier in your cycle.
Long Cycles (more than 32 days): Your chart may show increased fertility and ovulation later in your cycle.
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 and show a thermal shift that is recognizable by cervical mucus observation and cervical position.
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 at trends rather than individual temperatures. This can be a fluke or can be caused by any number of factors that can affect your temperatures. 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.
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.
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| Most Fertile Days |
Erratic Temperatures Daring Period: Likewise, 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: You may see a slight temperature dip
