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How do I Determine my Luteal Phase Length?

Tricia Christensen
Tricia Christensen
Tricia Christensen
Tricia Christensen

There are several ways to calculate luteal phase length. This is the length of time between ovulation and the day prior to menstruation. These methods vary in precision, and those concerned about a short luteal phase, or luteal phase defect may need help from a doctor to get a precise measurement of this interval.

A less “scientific” method is to count back from the date of the period. Since many women have a luteal phase that is about 14 days long, people can determine approximately when ovulation occurred, and how far this occurred after the cycle had begun for a month. This might be enough information to go on for people who have regular periods that are about 28 days in length. It is not always accurate though, since the luteal cycle can range from 10-16 days.

Ovulation kits may help women determine approximate ovulation time.
Ovulation kits may help women determine approximate ovulation time.

What women need to know to figure out luteal phase length a little more accurately is when they ovulated and when they menstruated afterward. It’s pretty easy to figure out when menstruation occurred, but ovulation tracking might be a little more involved. There are ovulation kits available at stores that could help women determine approximate ovulation time. Alternately people could track possible ovulation with basal body temperature readings, or with analysis of vaginal mucus, which is often taught in natural family planning classes.

Blood tests may help in determining exact luteal phase length.
Blood tests may help in determining exact luteal phase length.

With any of these tracking methods, date of ovulation could then be identified. A woman would then count days until she got her period. This time interval would essentially be the luteal phase, and might help determine whether the phase is appropriately long or too short. Anything less than 10 days is considered challenging because the uterus does not build up sufficient lining for a pregnancy to be sustained.

A luteal phase averages 14 days, but can run a few days shorter or longer.
A luteal phase averages 14 days, but can run a few days shorter or longer.

Some women have extremely irregular cycles and they may need greater help in determining exact luteal phase length. This is typically done under doctor’s orders via a blood test. Ovulation time still has to be discovered because the blood test has to take place about seven days thereafter. It evaluates the levels of progesterone in the blood and can much more accurately determine how long a luteal phase length is, and whether this poses a fertility issue that may need to be addressed.

The luteal phase occurs during the days between ovulation and the onset of the next menstrual cycle.
The luteal phase occurs during the days between ovulation and the onset of the next menstrual cycle.

There are fortunately potential treatments for a woman with a short or overly long luteal phase length issues. These can include giving progesterone to stabilize the length. These treatments are not necessarily required unless a woman is trying to get pregnant. Short or long luteal phases may not be medically significant in any woman uninterested in pregnancy

Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent WiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent WiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Discussion Comments

anon311122

I am having 40 days in between periods and am trying to conceive. I had a miscarriage a couple of months ago at 12 weeks gestation. I got diagnosed with hypothyroidism with that pregnancy but my levels have been therapeutic.

Could there be a problem with my progesterone levels because the length is so long between periods? Previously I was charting ovulation and BBT and I was ovulating most months around day 19-23.

anon276580

I have a seven-day menstrual cycle. I want to know the length of my luteal phase.

asha21

My period cycle is 32 days. Can you tell me how long is my luteal phase?

amypollick

@anon201189: Going from a 29-to-32-day cycle really isn't that much of a change. It's only three days, and many women find their cycles change from time to time, as they get older, unless they are on oral contraceptives.

If you're really concerned, then get an ovulation test kit from the drugstore and do the math from there. As another poster noted, I don't think the length of your cycle, long or short, really affects the length of your luteal phase. I'd say get the kit and do the math from there, or see your gynecologist about it.

anon201189

I need your advice. Previously I had a 29 day cycle, and it recently changed to a 32 day cycle but after that 32 day cycle, what is my luteal length?

TunaLine

Regardless of the length of your cycle, does the heaviness of your cycle make a difference in your luteal phase?

I have the normal 28 day period, but I do have a very heavy menstrual cycle.

I really want to get pregnant, can anybody tell me if this makes a difference? I would really appreciate it!

closerfan12

@littleman -- As far as I know, whether you have a long menstrual cycle or short menstrual cycle, your luteal phase length won't vary too much. That is to say, it will probably still be within the 10-12 day range (the average length of the luteal phase).

LittleMan

If you have a long menstrual cycle, do you have a long luteal length? I have a 33 day cycle, and have always wondered if this affected the length of my luteal phase.

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    • Ovulation kits may help women determine approximate ovulation time.
      By: AGL Photoproductions
      Ovulation kits may help women determine approximate ovulation time.
    • Blood tests may help in determining exact luteal phase length.
      By: spflaum
      Blood tests may help in determining exact luteal phase length.
    • A luteal phase averages 14 days, but can run a few days shorter or longer.
      By: auryndrikson
      A luteal phase averages 14 days, but can run a few days shorter or longer.
    • The luteal phase occurs during the days between ovulation and the onset of the next menstrual cycle.
      By: reineg
      The luteal phase occurs during the days between ovulation and the onset of the next menstrual cycle.
    • Potential treatment for a woman with a short or overly long luteal phase length issues includes giving progesterone.
      By: logos2012
      Potential treatment for a woman with a short or overly long luteal phase length issues includes giving progesterone.