I also wondered about the real "Day 1." As this page was loading, I figured out a practical way to find out. It takes 3 steps to find out.
We know that the luteum corpus is formed as soon as ovulation has ocurred. Then the luteum corpus begins to produce progesterone and this causes the elevations in temperature. This luteal phase is constant and began exactly 14 days before the beginning of the period. The beginning of our period, Day 1, is when the luteum corpus has disintegrated and no longer making progesterone. The low progesterone levels cause our lower temperatures.
So the average temperatures of our follicular phase (before ovulation) should all be lower than the average temperatures in the luteal phase (after ovulation).
Step 1. Pick "Spotting Day 1" as the first day of your menstrual cycle and count 14 days before. That was the day of ovulation and the beginning of the luteal phase according to this sample of temperatures. So take the averages of those two time frames. Before ovulation (follicular phase) and after (luteal phase).
2. Now, ignore the days we spotted and pick "Heavy bleeding Day 1" as the first day of your menstrual cycle and count 14 days before. Again, take the averages of the temperatures before ovulation and after for this sample of temperatures.
3. The averages that show the biggest difference between the two phases is most likely the "real Day 1."
When I did this, my average temperatures were more different when I counted "Heavy Bleeding Day 1" as the first day of my cycle. So for me, my "True Day 1" began on the days my heavy bleeding began and not the spotting.
My Example:
A. "Spotting Day 1": Follicular Phase Average Temperatures 36.23, Luteal Phase Average Temperatures 36.41. The difference = 0.18.
B. "Heavy Bleeding Day 1": Follicular Phase Average Temperatures 36.17, Luteal Phase Average Temperatures 36.52. The difference = 0.35.
P.S. I had three months worth of data to work with.
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I also wondered about the real "Day 1." As this page was loading, I figured out a practical way to find out. It takes 3 steps to find out.
We know that the luteum corpus is formed as soon as ovulation has ocurred. Then the luteum corpus begins to produce progesterone and this causes the elevations in temperature. This luteal phase is constant and began exactly 14 days before the beginning of the period. The beginning of our period, Day 1, is when the luteum corpus has disintegrated and no longer making progesterone. The low progesterone levels cause our lower temperatures.
So the average temperatures of our follicular phase (before ovulation) should all be lower than the average temperatures in the luteal phase (after ovulation).
Step 1. Pick "Spotting Day 1" as the first day of your menstrual cycle and count 14 days before. That was the day of ovulation and the beginning of the luteal phase according to this sample of temperatures. So take the averages of those two time frames. Before ovulation (follicular phase) and after (luteal phase).
2. Now, ignore the days we spotted and pick "Heavy bleeding Day 1" as the first day of your menstrual cycle and count 14 days before. Again, take the averages of the temperatures before ovulation and after for this sample of temperatures.
3. The averages that show the biggest difference between the two phases is most likely the "real Day 1."
When I did this, my average temperatures were more different when I counted "Heavy Bleeding Day 1" as the first day of my cycle. So for me, my "True Day 1" began on the days my heavy bleeding began and not the spotting.
My Example:
A. "Spotting Day 1": Follicular Phase Average Temperatures 36.23, Luteal Phase Average Temperatures 36.41. The difference = 0.18.
B. "Heavy Bleeding Day 1": Follicular Phase Average Temperatures 36.17, Luteal Phase Average Temperatures 36.52. The difference = 0.35.
P.S. I had three months worth of data to work with.
I hope it helps!
October 13, 2012 - 1:35pm-Carmen Gutierrez, Med Student
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