LH Surge question / Marquette Method

We are using the Marquette Method so we are detecting the LH Surge with a Peak reading on a clear blue fertility monitor. We also use mucus signs. We detected a peak on 5/1 and 5/2 and then it went back to high on 5/3. The Marquette Method says to consider three full days after the last Peak (LH Surge) as fertile.

Everything I have read says that you will ovulate withing 48 hours of the LH Surge and that ovulation can last for a maximum of 24 hours. So I have two questions.

  1. Why would you wait until 3 days after the last Peak detection? If ovulation happens within 48 hours of the LH surge then it should happen within 48 hours of the first detection right and not the second day of peak reading?

  2. Why wait 3 full days instead of 48 hours + another 24 for ovulation? Even if I use the last peak day we take the reading in the morning. So 48 hours after that is the morning of the second day after. 24 hours after that is the morning of the 3rd day. Why wait the entire 3rd day?

Thanks for any help you can give and God bless.

I don’t use Marquette, but hopefully I can still help!

  1. The LH surge is the luteinizing hormone, which surges just BEFORE ovulation and helps cause the release of the egg. It is not the start of actual ovulation. It is possible for it to take a little time for the LH to build up (first detection) before it truly SURGES (peak) high enough to induce the release of the egg. Hormones don’t act instantaneously.

  2. You are only taking a reading in the morning. The actual event of “surging” may still happen later in the day. Again, things don’t happen instantaneously and statistically these things can vary from person to person and from month to month. The “48hrs” and “24hrs” aren’t RULES… they’re statistics… and statistics have to taper off before you’re considered 100% safe.

This is all a matter of statistics… have you ever taken a course?
This is a nice representation of a statistically normal curve. The center, where the majority of the cases fall doesn’t cover EVERYONE… it covers most, but not all… you have to wait for the tail ends to truly taper off…

You have to wait because there is always a safety margin in any of the calculations for determining fertile and infertile days.

Also, with Creighton method, you have to wait until END OF 4TH DAY.

Also, with Billings in case of a second ovulation, normally occuring within 24 hours of the first . (fraternal twins)

Something else to consider, is the possibility of ovulating twice. It usually happens close to the first, but waiting a full 3 days would allow continued observation to determine if such an event happened.

I also use Marquette. This “breaks the rules”, but I shave off that third day. Based on my mucus observations, this seems like overkill to me. Have you asked this question on their message board?

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