The Cramp Arrived on Schedule. The Period Did Not.

Body  ·  The Reading Room  ·  9 min read  ·  Why the ovary can still send the cramp after it has stopped sending the period on time, and the short list of reasons that need a doctor instead

Based on the published research of Jerilynn C. Prior, MD, FRCPC, Professor of Endocrinology and Metabolism, University of British Columbia, and founder and Scientific Director of the Centre for Menstrual Cycle and Ovulation Research. CeMCOR biography  ·  Wikipedia  ·  her review in the BC Medical Journal

The cramp is a message from a system that is still running. It just stopped running on a calendar.

It starts in the second hour of the budget review. That low, familiar pull, the one you have known since you were thirteen, the one that means tomorrow you will need to plan around.

Except tomorrow comes and nothing happens. Nor the day after. You count back on your phone in the parking lot and the last period was fifty-one days ago.

So you type it, the way everyone types it at that point: cramps but no period. And the results give you pregnancy, ovarian cysts and cancer in the first three lines, which is a lot to take in between the car and the kitchen.

Here is the calmer and more accurate version. Informational, not medical advice, and worth taking to your clinician rather than instead of one.

This is a reading of published research. We are not clinicians; the findings belong to the researchers named below, and the plain-English version is ours.

The short answer: in your forties, the most common reason for cramps but no period is perimenopause. The hormones that build and shed the uterine lining are no longer arriving in their old order. Estrogen can run higher and more erratically than it did at thirty, progesterone often runs lower, and many cycles no longer release an egg at all.¹² The uterus still responds to those signals, so you can feel the build-up without getting the bleed on time. A shorter list of other causes, including pregnancy, fibroids and bowel trouble, needs ruling out, and one pattern of pain belongs with a doctor within weeks, not months.³

In this article: Why it happens · The estrogen part nobody mentions · The other causes, side by side · When it belongs with a doctor · The one move · FAQ

Why do I have cramps but no period?

Because the two halves of the cycle have stopped arriving together.

For most of your adult life the sequence was reliable enough to plan a vacation around. Estrogen builds the lining. An egg is released. Progesterone follows and holds the lining steady. Progesterone drops, the lining sheds, you bleed, and the prostaglandins that make the uterus contract produce the cramp you feel on day one.

In perimenopause, parts of that sequence start happening without the rest. Estrogen can rise and build the lining. If no egg is released, the progesterone half never shows up on schedule, so the signal to shed arrives late, or arrives in pieces. The uterus is doing what it has always done with the messages it is given. The messages have changed.

Henry Burger, the Melbourne endocrinologist who spent decades mapping this stage, put the scale of it plainly: in the late transition, somewhere between 40 and 60 percent of cycles are anovulatory, meaning no egg is released at all.² A woman who spent twenty-five years with a period you could set a clock by is now running a system where half the cycles skip a step.

That is why the cramp and the bleed have separated. It is not that something new has gone wrong. It is that the old timing has gone.

Isn’t estrogen supposed to be dropping?

Eventually. Not first, and not smoothly.

This is the part of the story most of us were never told, and it is Jerilynn Prior’s central contribution. Prior is an endocrinologist at the University of British Columbia who founded the Centre for Menstrual Cycle and Ovulation Research in 2002, and she has spent much of her career arguing that perimenopause is not a slow fade of estrogen. In her words, the levels are chaotic before they settle.¹

In the comparison she reports, follicular-phase estradiol averaged 175 pmol/L in premenopausal women and 225 pmol/L in perimenopausal women. Higher, not lower. Progesterone, meanwhile, tends to fall, with more cycles that never ovulate and shorter luteal phases in the ones that do.¹

High, erratic estrogen alongside falling progesterone is the combination Prior connects with heavier flow and more cramping. Her list of the signs that perimenopause has begun reads like a description of the last six months for a lot of women reading this: new heavy or longer flow, cycles of 25 days or less, new sore or swollen breasts, increased menstrual cramps, waking in the middle of the night, night sweats, migraines and mood swings.¹

Her centre has also described a hormonal pattern it calls a luteal out of phase event: a second estrogen surge in the second half of a cycle, when levels should be settling, which often lands around the start of the next flow.⁴ You do not need to remember the name. You need to know that a cramp with no bleed is one of the documented shapes this stage takes.

If the cramps are one item on a list that has quietly grown all year, the sleep, the heat, the shorter fuse, it helps to see the whole list at once rather than one symptom at a time. Start here.

Cramps but no period: the other causes, side by side

Perimenopause is the most likely explanation in your mid-forties. It is not the only one, and the point of this table is to make the rest of the list feel manageable instead of frightening.

Five of those six rows are common, treatable or harmless. The sixth is rare, and it has a clear rule attached, which is a great deal more useful than a vague worry.

Who else has measured this

Prior is not a lone voice on the chaos of this stage, and the most important safety line here comes from a different specialty altogether.

Henry G. Burger, AO, MD, FAA (in memoriam), was an endocrinologist at Melbourne’s Prince Henry’s Institute, now the Hudson Institute of Medical Research, and one of the founding figures of menopause research in Australia. His 2011 review in Menopause International estimated that 40 to 60 percent of late-transition cycles are anovulatory, and warned that FSH and estradiol measurements are of little diagnostic value in this stage because of their unpredictable variability.² He died in 2024.
Monash Health, in memoriam · Australian Academy of Science · his writing for The Conversation · the 2011 review on PubMed

Barbara A. Goff, MD, is Professor and Chair of Obstetrics and Gynecology at the University of Washington and an affiliate researcher at Fred Hutchinson Cancer Center. Her 2007 study in Cancer found that a small set of symptoms was predictive of ovarian cancer, work that fed the symptom guidance clinicians now use, because there is still no screening test for the general population.⁶
UW Medicine profile · ResearchGate · the 2007 symptom index on PubMed · interview, Ovarian Cancer Research Alliance

The U.S. Office on Women’s Health puts the fibroid figure in context: somewhere between 20 and 80 percent of women develop fibroids by 50, and they usually shrink after menopause, because they depend on the same hormones that are now changing.⁵
womenshealth.gov, uterine fibroids

The system is still running. It just stopped running on a calendar.

When cramps with no period belong with a doctor

Most of the time, this is the transition doing something untidy. The job is to know the handful of patterns that are not, so you can stop scanning for them every time.

The one move: give the cramp a date

Two months. Thirty seconds a day. The notes app you already use for everything else.

Each day, one line: cramp yes or no, bleeding yes or no, and anything else that showed up, a bad night, a hot flash, sore breasts. Nothing more elaborate than that. You are not meant to interpret it tonight.

The reason this beats a blood test is Burger’s point. In this stage, a single hormone result is a photograph of weather.² Two months of lines is the climate. It shows your clinician whether the cramps travel with a cycle that is lengthening, whether the symptoms cluster, and whether anything sits outside the pattern and deserves a closer look.

And it does something else, which is harder to measure. It turns a thing you keep worrying about into a thing you are keeping track of. For a woman who runs everything else on a spreadsheet, that is often the moment the worry gets smaller.

Common questions

Is it normal to have cramps but no period in perimenopause?

It is common. Estrogen in perimenopause often runs high and erratic while progesterone falls, and many cycles release no egg, so the uterus can respond to the hormonal build-up without shedding on time. Increased cramps appear on Jerilynn Prior’s list of early perimenopause signs.¹²

Could cramps but no period mean I am pregnant at 45?

It can. Pregnancy remains possible in perimenopause until you have gone twelve months without a period. If you have had sex since your last period, a home test is the quickest way to take that question off the table.

Can a blood test tell me if it is perimenopause?

Not reliably on its own. Henry Burger’s review found that FSH and estradiol swing so unpredictably during the transition that single measurements are of little diagnostic value.² A record of your cycles and symptoms is usually more informative.

When should cramping without a period worry me?

See a doctor promptly for severe or one-sided sharp pain, fever, a positive pregnancy test, or any bleeding after a full year without periods. Book within weeks if bloating, pelvic pain or feeling full quickly is new and happens more than 12 times a month.³

Can fibroids cause cramping without a period?

They can cause pain, pressure and heavy or painful bleeding. Somewhere between 20 and 80 percent of women have fibroids by 50, and they usually shrink after menopause.⁵ An ultrasound can show whether they are part of the picture.

Nothing went wrong on day fifty-one. The clock you had for thirty years has simply been handed back.

Related reading: why the week before your period got harder, what the transition does to the midlife brain, and the night sweats that arrive alongside it.

On the researchers. Jerilynn Prior is an endocrinologist and researcher, not your clinician; her reviews describe patterns across groups of women and cannot explain any individual symptom. Henry Burger, who died in 2024, is cited for his 2011 review of the endocrinology of the transition. Barbara Goff is a gynecologic oncologist cited for her work on ovarian cancer symptoms, not as a source on perimenopause.

References
1. Prior, J. C. “Clearing confusion about perimenopause.” British Columbia Medical Journal, 2005, 47(10). bcmj.org. See also Prior, J. C. “Perimenopause: the complex endocrinology of the menopausal transition.” Endocrine Reviews, 1998, 19(4):397–428. academic.oup.com
2. Burger, H. G. “Unpredictable endocrinology of the menopause transition: clinical, diagnostic and management implications.” Menopause International, 2011. PubMed
3. American Cancer Society, “Signs and Symptoms of Ovarian Cancer”.
4. Centre for Menstrual Cycle and Ovulation Research, “Luteal Out of Phase Event (LOOP)”.
5. U.S. Office on Women’s Health, “Uterine fibroids”.
6. Goff, B. A., Mandel, L. S., Drescher, C. W., et al. “Development of an ovarian cancer symptom index: possibilities for earlier detection.” Cancer, 2007. PubMed

Written by Nora Whitfield for Blue Leaf Journal. Updated: 15 September 2026.