Does the moon affect your menstrual cycle?

/Does the moon affect your menstrual cycle?

Does the moon affect your menstrual cycle?

My Hormonology

Chances are, at some point, you’ve heard that menstrual cycles are somehow tied to cycles of the moon.

Of course, as you probably know–primarily from teen werewolf movies–people have long speculated that the changing phases of the moon have an effect on other aspects of human health and behavior, too.

For instance, past research suggests that the full moon may be linked to an increase in unexplained strokesgastrointestinal bleeding and seizures.

However, the link between the moon and humans isn’t exactly clear-cut.

In one recent study, researchers found that on nights when the moon is full, we sleep 20 fewer minutes….only for these results to be completely contradicted by a later study that shows the moon doesn’t affect our sleeping habits at all.

But, perhaps the most surprising revelation to come out of moon research is that, according to the majority of the studies, folks don’t get any crazier around the full moon–despite the many books and movies attesting to it.

Anyway, what about the link between a woman’s menstrual cycle and the lunar cycle? I mean, that’s why we’re all still reading this post, right?

Well, let’s start off with a bit of backstory: For generations, a woman’s monthly cycle has been tied to the moon cycle likely because they’re about the same length–with a “typical” menstrual cycle lasting 28 days and a lunar cycle lasting 29.5 days.

In addition, folklore often suggests that women are more likely to be fertile around the full moon–possibly because the fullness of the moon makes people think of fertility and pregnancy while the darkness of the new moon makes people think of emptiness. Or it may be tied to the idea that farmers who sowed seeds around the full moon had a better harvest.

So, over the years, scientists–a naturally curious bunch–set out to see if there is any true link. And what did they find?

A 1986 study and a 1980 study actually did find that a woman’s menstrual cycle was likely to be in sync with the moon’s phases.

But, don’t go planning a full moon party just yet.

The first study cited found that women were more likely to menstruate during the new moon. Meanwhile, the second study I mentioned found that women were more likely to ovulate during the new moon, completely contradicting the other study.

So, which study was correct? Maybe neither. A 2013 study in the journal Endocrine Regulations that monitored 74 women’s cycles for a full year found no correlation between the menstrual cycle and moon phases. Any link we find can be chalked up to pure coincidence.

Think this is the end of the moon-and-menstrual-link story? Not so fast….

An interesting 1990 study in the journal Psychiatry Research found that bright light at night can help regulate the menstrual cycle. In the study, women with abnormally long cycles of about 45 days who slept with a 100-watt bulb turned on at night in their bedroom from Day 13 to Day 17 of their cycle successfully shortened their periods to about 33 days.

And another intriguing 2005 study out of India found that women who conceive while ovulating during the full moon are more likely to give birth to boys. On the other hand, women who conceive while ovulating three days prior to the full moon are more likely to give birth to girls. The researchers chalk it up to a change in vaginal fluids and basal body temperature brought on by the changing moon phases.

This hints that before electricity and the light bulb, shifts in the amount of light at night during the moon’s various phases could possibly have played a significant role in our menstrual cycle–maybe by affecting certain body processes impacted by light exposure, such as the production of the hormone melatonin, prompting all that folklore tying our menstrual cycle to the moon cycle.

What do you think? Have you noticed any link between your menstrual cycle and the phases of the moon?


By | 2017-10-10T13:34:09+00:00 August 11th, 2014|hormonology tip|65 Comments

About the Author:

Gabrielle Lichterman, founder of Hormonology® and a longtime women’s health journalist, pioneered the growing movement among women to live in sync with their menstrual cycles and know more about all the ways their hormones impact their moods, health and behavior. This movement was launched in 2005 with Gabrielle's groundbreaking book, 28 Days: What Your Cycle Reveals about Your Love Life, Moods and Potential, and her creation of Hormonology®. She offers a variety of tools--including her popular free Hormone Horoscope® app, eBooks, infographics, videos and tips--to share vital information about hormones.


  1. Anonymous January 3, 2018 at 7:53 am

    Did anyone commenting actually read the article?! There’s no link. The only possible link is the light source. So unless you sleep with the moon bearing down on you there is no reason the moon would impact your body or mind.

  2. Anonymous November 3, 2017 at 4:20 am

    Well just 😵😵wow.

  3. Amy May 7, 2016 at 6:46 pm

    I’ve noticed that I’m ovulating when it’s full moon. Thanks to an app where all the info is stored, I can see the statistics and check the history. So, was curious about the link between the menstruation and full moon.

  4. Kati March 11, 2016 at 3:32 pm

    Oh my god, I’m not crazy! My period almost always starts on the full moon and I feel like my cramps are so much worst when it does. I’m even on birth control pills and they don’t change the timing whatsoever. It doesn’t matter if I’m on the placebo pills or not, if it’s a full moon – it’s shark week.

  5. Lisa February 23, 2016 at 9:54 am

    I was reading this because we just experienced a giant full moon and my period came early…

  6. Kitanja.K. January 17, 2016 at 12:48 pm

    Everytime the moon comes my period comes when the blood moon came my period came the morning after the pain was terrible

  7. Lyla December 23, 2015 at 10:51 pm

    When I was a teenager, I used to run away from home BEFORE getting my period. Returning after I got it. Now It seems it does coincide with a the full moon most, but not all of the time. I have been watching. It is very difficult to get over a period if it is a full moon I have noticed.

  8. Barbi Smith December 22, 2015 at 1:12 pm

    No offense, but it’s not rocket science. lol. or Maybe it is……. Our bodys’ are composed of ninety percent water. Think about it… When the moon is full the earths gravitational pull is at its strongest. The moon affects the tides as such.

  9. skarkey November 30, 2015 at 8:40 am

    Joan says that when her altitude is raised she may menstruate early – i would guess that either a drop in air pressure is more likely than being closer to the moon which is on average 239,000 miles away but with a minimum distance of 225,622 miles and a max distance of 252,088 miles giving a whopping 26,465 miles variation.
    The highest plane is only 6 miles high – which is a pitiful distance compared to the annual average change in distance – the change in gravitational effect that an earthbound altitude change brings is not likely to be felt

  10. Carol October 31, 2015 at 7:35 pm

    Why do women lose their menstrual cycle when below ground for extended time periods as well?

  11. Anonymous October 29, 2015 at 5:08 pm

    My period seems to usually start around a full moon, and it could just be a coincidence, but periods that start closer to the full moon seem to be shorter but heaver for the time they last.

  12. Joan October 27, 2015 at 11:41 am

    I’m 54 years old and have had my period almost exclusively on a full moon my entire life. When I was younger, my cycle was much longer, though. I would have a period every other month…but more times than not, on a full moon. So, If I were to be added to a study, I’d say it is pretty conclusive that the full moon does affect a women’s cycle. Maybe it’s the light…maybe it’s the gravitational pull. I don’t know. All I do know is that wow…it’s a full moon and I have my period. So much for romantic walks under a full moon! LOL

    P.S. I’ve also noticed that elevation can play a part in my cycle, too. If I’m close to it starting and go on an airplane, I will get my period or spot. The same thing happens if I drive up to a higher altitude.

  13. Michelle October 24, 2015 at 6:38 pm

    Full moon cycler here. No matter how many times I have been on or off birth control I always end up bleeding during the full moon. I am definitely a “red witch” type persona on top of it

  14. Sarah K. Harm October 19, 2015 at 9:46 am

    Gabrielle, the moon may be linked but perhaps not everyone is linked to the same PHASE the moon is in? I’m not sure. But, in any case, Indian studies might provide more accurate results than American/European ones

  15. Sam October 11, 2015 at 12:28 pm

    The 2015 blood moon in september caused me to miss my period completely. I am in birth control pills that I stop for 7 days to allow my period to come and during the blood moon it did not come that month whatsoever. I had extremely tender breasts to the point I thought for sure I was pregnant…alas, 28 days later my period is here. Thanks blood moon.

  16. Shaye Taylor October 7, 2015 at 5:46 pm

    I have usually been a regular kinda gal, I am on Birth control pills, My cycle has been out of whack with this new blood moon that we had, I started my period 1 week early on that specific day, weird for me cause I was feeling very crampy all week leading up to it and it was a period that lasted 11 days instead of 5 like it usually does.. I don’t think its a coincidence at all, this moon stuff is the real deal!

  17. Nicole September 30, 2015 at 4:38 pm

    I’m also late. Freaking out. I used cyclebeads (app)
    To determine the date i would start and to keep track of my cycle. It also tells you the fertile likely to get pregnant and not likely to get pregnant days, based on if ur 28-32 day cycle. Well I thought I was 28-32 day cycle. I had been starting around the end of month to 1st in May June July. Well app predicted me to start menstual aug. 26 and it was dead on. Then it said I would start this month sept 22 for whatever reason I have not started. It’s the 30. I’m late. And I’m hoping its becuz the blood moon or stress. I don’t no but if I song start tomorrow I’m getting a test. I just read others comments about being late and I’m normally regular except maybe once or twice a year I’ll be a few days off-week at most.

  18. Rand Sheares September 29, 2015 at 9:41 pm

    I got my period on September 1st and then I got my period again on the 27th!!! This was the first time it had ever happened to me and my period was always regular for the most part, give or take a few days. I was starting to get worried about it until I started doing research on the connection between the moon and menses. 🙂 now I’m not worried and I’m convinced that is the culprit. We are some fascinating creatures my GOD!!

  19. Nicki September 28, 2015 at 9:51 pm

    My cycle started a week early due to the supermooon last night and my pains are twice as bad as they usually are….

  20. angie September 28, 2015 at 8:44 pm

    My period is late due yesterday its always on time Iam not pregnant. .. I am 38 ,I think its running late due to the supermoon last night ….

  21. Sarah September 28, 2015 at 10:46 am

    This is freaky reading all of these! I always gave birth ona full moon to all three of my children. My period was a couple of weeks late and I was starting to worry that I was pregnant! I did a test almost two weeks ago which came back negative, then last night (the night of the supermoon/blood moon) my period finally came. Coinsidence?! There must be a real link out there. Sarah

  22. Periods of the Moon | September 28, 2015 at 7:04 am

    […] Source: […]

  23. Jeannie September 28, 2015 at 1:23 am

    Sharing the weirdest experience I had tonight. A bunch of us neighbors were out in the cul-de-sac tonight, just watching the blood moon/eclipse. I am almost 53 and haven’t had a period in nearly a year. Nothing. No spotting or anything. Right at the point where the moon was completely covered by the eclipse, I felt this sudden “gush” down there and thought, “What the heck?!” I rushed inside and found out my period had returned–at exactly the moment that the eclipse was at its peak! No kidding! Completely freaked me out. Add to that, my legal name is Diana–the Roman goddess of the moon. Coincidence? I don’t know, but it sure shook me up.

  24. Super releaved September 26, 2015 at 7:25 am

    I’ve been bleeding for 20 days – really unusual, plus terrible bloating, pain etc. Blood tests all came back normal but I was really worried. Then I just found out there’s a super moon on Sunday! Now I’m convinced this is what’s caused my woes and I’m not worried any more. Also, my girlfriend’s cycle is always in sync with the moon. I think people should talk about this a lot more!

  25. PassinThru September 19, 2015 at 12:52 pm

    If the average menstrual cycle is 28 days, but ranges from 21=35 days, then there are women for whom the cycle is 29.5 days. So they will naturally believe their cycles are tied to the moon. And there are some women who will never really take note except on those occasions where their period comes on a full moon night. Finally, women who believe they are tied to the lunar cycle are more likely to comment on this thread than those who aren’t. So it’s perfectly reasonable that (1) many people believe they’re tied to the lunar cycle and (2) the Moon has nothing to do with it. Drea M and BIGBOUD above are examples who are clearly not tied to the lunar cycle. It’s much easier to see what you want to see in data than it is to see what’s actually there.

  26. Fifi September 7, 2015 at 7:43 am

    Hullo ladies! Im 25 and for the past 10 yrs,my cycle has been typical moon work.Af always showed up exactly at new (after 29 days) but my cycle got disorganised after i had a miscarriage in july this yr.Im praying realy hard so that i can go back to the normal moon cycle bse its a lot easier than predicting when Af will show up.Thank u Ladies.

  27. alexis rios August 24, 2015 at 12:01 am

    I have only wished I knew this all my life to plan my honeymoon * which I lucked out on ;*
    vacations ,and other beachy days!

    I read this article and now this whole year my day falls on a full moon! now I know when to wear a tampon to be safe, or plan vaca because this method of schedule has never failed! every time there’s a full moon mother nature is in full circle in my life too!

    so much scientific studies ha but I knew that already, there is a God he created us the moon and our cycles ! yes scientists you may want to study the bible more hmm and listen to your own bodies I know scientists have to be at lest 1 woman why did she not just follow her own period jeez! I think they like to belive their own non belief jeeberish ,so much they won’t debunk the truth once found what about this study !!
    there is certainly more to life ,the moon, tides , our bodies cycles minds and balance . just by watching nature and my body

  28. Anonymous August 18, 2015 at 5:15 am

    I also had two periods last month for the blue month and I’m normally regular.

  29. River August 9, 2015 at 2:39 am

    We had 2 full moons in July and like clock work my period hit 1 day before each full moon. 2 full moons and 2 periods in 1 month. I’m thinking there is a connection.

  30. Zoe M. Morgan July 24, 2015 at 1:42 am

    Okay, well the father actually decides the sex of the baby. Not the woman. A woman has two ‘X’ chromosomes and a man has an ‘X’ and a ‘Y’.
    The mother always gives one of her X chromosomes to the child, but the father either delivers his X or his Y, delivering an X means a female child and a Y will bring a male.

    So that must also be coincidental.

  31. BigBoud July 19, 2015 at 3:41 pm

    Ok, I’ve read a few articles like this and I have a burning question: what about the women who have a longer (or shorter) cycle? Mine has always been 32 days, so if it happens at the same time as a new or full moon, that’s a coincidence. This is true now when I live in a city with black-out blinds, and it was true when I lived in the country in a bedroom with west-facing windows through which the full moon shone onto my bed. I’m sure I can’t be the only one!

  32. MissC July 4, 2015 at 2:52 pm

    I just googled this as I always start my period bang on the full moon. I’m so glad to see it’s not just me – it seems to be a proper *thing*. Really interesting.

    I was on the Pill for a few years, which obviously changed my cycle – but even then, on full moon day, wherever I happened to be in that artificial cycle I would have a bit of a breakthrough bleed – almost as if my body was trying to stick to its natural rhythm despite the chemicals.

    I came off the Pill recently and next full moon, sure enough, there it was!

  33. Drea M. July 2, 2015 at 2:19 pm

    I’ve charted my cycled on and off for about 10 years of my life.

    Though I’ve never been disciplined enough about it to say for sure, it does seem that my cycles change with the time of year and length of days. I tend to ovulate with the full moon around winter and early spring, then I start my period around the full moon during the summer and fall.

    This cycles with the supermoon my cycle day one, first day of full flow, was yesterday night.

    It was an intensely emotional luteal phase, by the way.

    So, my cycles vary in length throughout the year from 26-28 days.

    The Athena Institute, The Red Web, and the Society for Menstrual Research are all excellent places to support research about this topic.

    Great article, thank you!

  34. Emma July 1, 2015 at 9:48 am

    I ovulate on the full moon , always have but only figured it out while I was doing fertility treatments , instead of ovulating or bleeding when I was supposed to from the drugs, my cycle would line up with the moon x

  35. Emil June 29, 2015 at 7:57 pm

    Wow this is not what I was looking for.. But since you’re talking about the relationship between lunar cycles and menstruation, and have a simple comment system 😉 I’ll take the opportunity to mention why I believe that there IS a relationship between menstruation and the lunar cycles. Feel free to contact me about what you think.

    – When reading about the origin of the moon, the Great Impact Hypothesis is often mentioned as the most believed theory of how the moon was created. In a nutshell it’s about Theia, a Mars-sized planet, partially colliding with “ancient Earth”, sending debris of both entities (or mostly debris of Theia) into a swirl around “new earth”, eventually clumping up and becoming the moon orbiting Earth.

    Adding the theory of lunar cycles affecting menstruation with the theory of two similar sized entities “colliding” and forming a smaller entity with a strong relationship to its “parent”; made me think of (maybe you guessed it) how creatures on earth procreate.
    I strongly believe there is a relationship between the lunar cycles and menstruation…
    Another theory I have concerning all the differences in how, when and for how long a person menstruates or experiences their menstruation, is something like how the moon is/was “aligned” when a person was born or started menstruating.
    Being born in June in Europe would probably have a different effect than being born at the same time in America, because of different gravitation pulls from the alignment of the moon. If it’s instead related to when a person start menstruating it probably gets even more hard to predict the layout of the cycles.

    Sorry for the essay.. This is the first ventilation I’ve had since I started thinking about the matter, and it was the first that popped up when searching for “moon cycle and menstruation” 🙂 It was a very interesting read as well!
    Hope my thoughts has given some new perspective.
    Peace <3
    I'd like to mention that all of my sources are from wikipedia, I'm mostly just expressing my own thoughts and recent believes/theories about the topic.
    More Peace <3<3

  36. Sage June 3, 2015 at 10:19 am

    Definitely been synching up with the full moon for the past months. It’s intense and interesting to see how many women’s cycles have been following this cycle as well

  37. Anonymous June 2, 2015 at 10:52 am

    Today is a full moon, and I just started my period. It’s currently 2 weeks early…

  38. sosicapri May 31, 2015 at 12:26 am

    At the beginning of the month i get all these symPtoms fatigue , anger i can really snap!
    28 days in a cycle and 7 in a period i have seizures for life who do you think is beating my butt lol…

  39. Katie M May 21, 2015 at 9:11 am

    I track my cycle by the moon phases, rather than counting, it’s easier for me to remember and it synchronizes perfectly. I ovulate during the full moon and menstruate during the new->waxing crescent. I have a son, conceived during a full moon cycle.

  40. Anonymous May 1, 2015 at 9:00 pm

    I always had menses during a full moon like clock work no dormitory effect could disrupt it except metapause but I don’t miss it and the price of tam pax has gone up plus the hassle of birth control and under ware so cheer up ladies the best is yet to cum.

  41. Mary Knoles March 22, 2015 at 11:26 pm

    My cycle has always been linked to the full moon almost to the day every time. I really hope they do more research on this, because the moon affects our planet so much (tides etc.) and the littlest things seem to effect evolution greatly. For example, the slight tilt on our axis making seasons and therefore seasonal flowers. I just think that there must be more.

  42. Luna March 21, 2015 at 4:39 am

    I wonder if contraceptive pill has anything to do with some women being out of sync with moon, and if being in sync with moon has any relationship to fertility. It isn’t primitive or superstitious to suspect that our bodily cycles be linked to the cycles of the planet we evolved on, after all, our sleep cycles are regulated by the sun and animals hibernation and migration cycles are linked to cycles of nature.

  43. Kacey Broderick March 7, 2015 at 2:37 am

    I’m male, and I’ve been wondering about this for a couple years. I noticed it seems that some women may be also ovulating at new moon. This possibility of the moon’s influence on hormone levels leads me to believe that medications like birth control, etc. might work more harmoniously if they were designed to sync with the moon cycles.
    I figure that it must be something about gravity and magnetism and the location of the large mass of the moon in relation to the location of the large mass of the sun, and how this tug-of-war may perhaps magnetically polarize hormones or make certain types more active in cycles. This would of course also affect men and animals.

  44. Cathy March 6, 2015 at 8:33 pm

    I am right in the middle of perimedopausal at 48..I had a regular cycle with emotional pms 10 days ago.. today the fullmoon is in full beautiful form ….and yes today i started my cycle again. ..i beleive my body is clean from a healthy lifestyle so nature influences it …Beautiful. …im still a women…

  45. susiaustria March 6, 2015 at 5:49 pm

    Same with me, as long as I can remember and that is 25 years of menstruation I always get my period on full moon, there must be a connection, without daubt.

  46. Alison February 21, 2015 at 12:47 am

    I have journaled my periods for a long time! I have very bad PMS symptoms.
    Over the last couple of years I have studied my periods along with the moon phases. I’ve been menstruating on the full moon!
    Up until September 2015 and I’ve switched over to the new moon!
    There are many differences between my symptoms and the phase of the moon.
    Not sure about anyone else but February the whole month I have been prementrual symptomatic! Is this because of the super moon?

    Help! We need answers!

  47. Nancy February 17, 2015 at 9:22 pm

    As soon its close to a new moon, i begin to feel the pms symptoms such as heavy breasts and a bloated stomach band I bleed on or close a to a new moon, it has always been like that.

  48. Moon cycle and health February 4, 2015 at 6:02 pm

    […] from 21-35 days and is on average 28 days. So they seem quite similar. On the other hand you can discuss on the link between menstruation and moon cycle. Some say it is pure coincidence that the phase has […]

  49. camille February 4, 2015 at 1:34 am

    Full moon, bloated stomach and bloody under garment, sounds about right. Thanks, Mother Moon!

  50. Anne February 3, 2015 at 9:51 pm

    Well for the first time I pay attention to this and as I read other comments I am like most others 😉 menstruating on the fulll moon. Guess that says more than scientific reports 🙂 and also just read that you are then balanced body/mind.

  51. Nadia February 3, 2015 at 6:48 pm

    It’s a full moon and i’m bleeding. So happy to read it’s not just me! Been tracking it for a year now and it has been consistent. In awe of the beauty of nature. Love and Light Ladies 🙂

  52. MS J January 27, 2015 at 7:03 pm

    Yes more research is needed in this field. I too menstuate on a full moon and i just think its amazing and demonstrates our direct planetary connection.

  53. Kj January 2, 2015 at 5:08 pm

    I seem to ovulate with the full moon. I’ve had five boys. No girls. Any coincidence?

  54. Gabrielle Lichterman December 6, 2014 at 10:11 am

    Hmmm….sounds like the researchers need to revisit this moon/cycle connection thing! I’ll keep you posted if I come across any new studies!

  55. Cassie December 6, 2014 at 3:40 am

    I almost always start my period on the full moon. I never really made the connection until I was on more of a late evening schedule when my husband (an ER nurse) began to work evenings. We began taking regular walks at night due to this, and it became apparent that when the moon was full aunt flo was just coming into town. I gave birth to our son close to two weeks early…and yep he was born on the full moon (on a harvest moon, the biggest and brightest full moon of the year).

  56. Donnie December 6, 2014 at 12:49 am

    It’s a sure thing. When the moon becomes full or at its fullest my body starts to do the Watussi and then it hits me like a lightening bolt. I think because our bodies are made up of water. We are effected just like the ocean tides, they come in harder and faster with a full moon. It’s bizarre but factual.
    I guess we just have to go with the flow.

  57. lacey December 4, 2014 at 2:22 pm

    I always start bleeding on a full moon I thought I was crazy when I told people about this because of the looks and responses I got. So today I decided to Google it and ran across this and a few other really good articles. I feel so much better seeing all the other responses and knowing I’m not the only one. .. crazy or not I’m not alone 🙂

  58. Charmaine December 3, 2014 at 4:37 pm

    My period always starts on the full moon. Always. PMT couple days before.

  59. gina November 6, 2014 at 10:25 pm

    For years like clockwork, I always menstruated as soon as the moon became full, and the days leading up to it I had pms. No way could this be coincidental.

  60. Sutherland October 31, 2014 at 9:14 am

    October2014 we had a special moon, I was trying to get pregnant and thought seems like the perfect time so the week of the full moon we baby danced everyday or second day and sure enough I became pregnant sadly at almost five weeks I lost the baby but u can bet I’ll be going off the moon from now on

  61. iesha October 30, 2014 at 12:37 pm

    My husband and I went the beach that night….It was my first time witnessing a blood moon…Beautiful it was!!! But I too woke up that night in a pool of blood….Very Freaky!!!!!

  62. […] has been a lot of discussion of the “full moon effect“: specifically whether the light of the full moon obscures the light of the Northern Lights. […]

  63. Renee October 9, 2014 at 4:03 am

    My monthly menstruation began on the blood moon, help I’m a werewolf!! lol

  64. mary e. October 8, 2014 at 6:30 pm

    I had the worst PMS. And i do not get PmS i cried every day 1 2 3 4 5 and 6 I got my period am on 7 October all is fine no crying and very productive went like 37 no i am not pregnant in my cycle is this some kind of super moon this year as it was couple with an eclisp this morming?!

  65. Laura October 8, 2014 at 1:56 am

    My cycle has snapped to the moon cycle, to the minute. I begin menstruation within an hour of the full moon, depending on where I am on the planet. When I am moving across country, or just travelling, my cycle tends to be disrupted by a couple of days. I have often attributed this to stress and other factors (particularly in August when we had the super moon). But when I’m in one place for a few weeks, it never fails: I start my period when the moon is full. Crazy.

    I’ve also noticed that when other planetary influences are at play, particularly the blood moon this October, my PMS and other pre-menstrual symptoms intensify. I wish we had more research about this phenomenon.

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