IBS Before Your Period: What to Log Across Your Cycle

A few days before your period your gut gets restless, and diarrhea arrives with the bleeding. Many women with IBS know this pattern. In Sam's symptom diary you log abdominal pain, bloating or diarrhea per day as mild, moderate or severe, and bleeding goes into cycle tracking; Health History then shows symptom days and period days on one month calendar. Whether your symptoms follow your cycle is for your doctor to judge.

How IBS is diagnosed, and what a doctor asks in general, is covered in IBS and your doctor: what to write down. Which blood tests and scopes belong to the work-up is in What kind of doctor for IBS? Colonoscopy and blood tests. What Sam keeps for IBS is on the IBS page. This post is about the days before and during your period.

Why does IBS often get worse around your period?

A 2010 systematic review points that way; 13 of the studies it pooled looked at the menstrual cycle. Women with and without IBS reported more bowel symptoms during their period than at other times of the cycle. The studies most often found looser stools, bloating, abdominal pain and more frequent bowel movements. Symptoms were stronger in women with IBS.

The reason is not fully clear. The German S3 guideline on IBS says newer studies suggest that sex hormones play a part in IBS, because it is more common in women before menopause. It links estrogen to how the gut moves and how sensitive it is to pain. A 2014 review describes hormone changes across the cycle affecting gut function in women with and without IBS. The review says the hormones are not a cause of IBS, but they likely shape when it starts and how it feels. It also calls the mechanisms poorly understood.

Then there is the period itself. IQWiG, Germany's health information institute, says period cramps trigger nausea, vomiting or diarrhea in some women. The NHS also lists stress and anxiety as IBS triggers. No study can tell you which applies to you.

Is diarrhea during your period normal with IBS?

It is common, even without IBS, but not automatically harmless. A Canadian study surveyed 156 healthy women who had not reached menopause. 73 percent had at least one gut symptom in the five days before or during their period. Abdominal pain was reported by 58 percent before and 55 percent during the period. Diarrhea was reported by 24 percent before and 28 percent during. The study was small, recruited at gynecology clinics and relied on memory.

Reviews also find more diarrhea than constipation around the period. New or worsening symptoms, and any sign under "When should you not wait for the next cycle?", need a doctor.

When could cyclical gut pain be something else?

Period-linked pain is not always from the bowel. IQWiG says endometriosis patches can sit on the bowel and cause problems and pain when passing stool. The pain often comes with the period. The NHS lists irritable bowel syndrome among the conditions with symptoms similar to endometriosis.

The European ESHRE guideline names these, among others, as reasons to consider endometriosis:

• Period pain.
• Deep pain during sex.
• Pain when passing urine.
• Pain when passing stool.
• Painful bleeding from the rectum, or blood in the urine.
• Fatigue.

This list is not a self-test and not complete; whether endometriosis is a possibility is for a gynecologist to judge.

The German IBS guideline lists gynecological causes among conditions that can look like IBS. Its basic work-up includes a gynecological check. Your doctor works out where your symptoms come from, not your diary.

So log period pain and painful bowel movements apart from general tummy pain. ESHRE finds no evidence that a diary leads to a faster diagnosis, but it can prepare the conversation. For how to describe endometriosis symptoms, see endometriosis: prepare your symptoms for the doctor. More on bloating and diarrhea with endometriosis or IBS is on the endometriosis overview.

What should you log across a cycle?

Give every day an entry, including days without bleeding and without symptoms:

• Bleeding: yes or no, and how heavy.
• Gut: abdominal pain, cramps, bloating, each rated on the same scale.
• Bowel movements: how often, what they looked like, diarrhea or constipation. The appointment post above explains the Bristol stool scale.
• Pain when passing stool, and period pain, kept apart from tummy pain.
• What it cost you: days off, cancelled plans, nights you were awake.
• What you took, including over-the-counter remedies, and whether it helped.
• What else changed: stress, short sleep, an infection.

What does one cycle look like in a diary?

Here is one way a cycle could look on paper. "Pain" is pain strength from 0 to 10; "Stools" is the number of bowel movements and the Bristol type.

This example is invented: not a real person, not a benchmark, not a result. Do not put off an appointment because a diary looks harmless. If things get worse or a sign from the last section appears, go sooner, even mid-cycle.

Over several cycles you can count the days with gut symptoms around your period and on the other days. Whether that pattern fits IBS, something else or both is for your doctor to judge.

The sources set no number of cycles for IBS. For a PMS diary, IQWiG suggests at least two to three months. Ask your doctor what period they want to see.

How do you log your period and gut days in Sam?

In Sam's cycle tracking you pick the flow for each day, from Spotting to Heavy. Under "How it went" you tap set options, such as "Changed my plans" or "Woke me at night". There is no free-text note field. Periods already in Apple Health come in when you open cycle tracking, up to two years back, if you allow access. The import never overwrites a day you logged yourself.

The same sheet has an "Also noticing" section with Abdominal cramps, Bloating, Headache, Mood changes and Breast pain. Tapping Abdominal cramps or Bloating saves it as moderate. "More symptoms" opens the full list. There you find Abdominal pain, Diarrhea, Constipation and Pelvic pain and set mild, moderate or severe. These entries go into the symptom diary like any other symptom. Period pain has no ready-made entry, so add it under "Other" as your own symptom.

In Health History, the month calendar shows symptom days and period days as dots. A dot does not say which symptom or how strong.

For the appointment there are two PDFs. The Cycle report shows your cycles, their length, bleeding days per period and bleeding between periods, but no gut symptoms; the summary heading in the PDF mentions symptoms but contains none. You create the monthly report yourself. It is not a doctor report, and there is no doctor report for IBS. The monthly report shows your symptom days on a calendar and your five most logged symptoms, but no period days. It needs notifications allowed, Apple Health access and your answer about chronic conditions saved. From the second report on, you must also have logged how you felt on at least 15 of the last 30 days: Good, A bit off or Sick. Symptom entries do not count toward that.

In the calendar, the statistics and the reports, Sam does not place your gut symptoms on cycle days and calculates no link. When you log, Sam can offer to copy the symptoms from yesterday or from the same day of your last period; that is an entry shortcut you tap yourself. You compare the two reports yourself. Stool type and the number of bowel movements are not recorded in Sam, so those stay on paper.

What changes in perimenopause?

For IBS, not much is known. The 2010 review found too little data to judge how menopause affects IBS symptoms. The 2014 review describes conflicting studies. In one, abdominal pain increased after menopause. In another, it was lower in women over 50.

The NHS says periods may become irregular, lighter or heavier during perimenopause. So log the days you actually bleed. Any vaginal bleeding after more than 12 months without a period needs a doctor's check, even if it is only spotting. For tracking this stage, see menopause symptom diary: what to track.

When should you not wait for the next cycle?

These signs need an urgent appointment today, even if you already have an IBS diagnosis and even if they only appear around your period:

• Blood in your stool, bleeding from your bottom or bloody diarrhea.
• Losing a lot of weight for no reason.
• A hard lump or swelling in your tummy.
• Symptoms that suddenly get much worse.
• Tummy pain with unusual bleeding or abnormal discharge from your vagina.
• Shortness of breath with palpitations and paler skin than usual.

Outside practice hours, use your local out-of-hours service (NHS 111 in the UK).

Also get these checked before anyone calls it IBS, and if you already have an IBS diagnosis:

• Fever.
• Anemia on a blood test.
• Unusual paleness.
• Symptoms that keep getting worse.
• Diarrhea that wakes you at night.
• Symptoms that first started after age 50.
• Smaller unintended weight loss.
• Bowel cancer, inflammatory bowel disease or celiac disease in your family.

These lists are not complete and are not a self-test. New or lasting bowel symptoms are worth a doctor's visit even without any of these signs. The first list follows the signs for which the NHS advises an urgent GP appointment or NHS 111. IQWiG says blood in the stool should as a rule be checked by a doctor. The German S3 guideline names, among others, fever and other signs of inflammation, anemia, weight loss, blood in the stool and steadily worsening symptoms. A summary of the American Gastroenterological Association guideline adds nocturnal diarrhea, onset after 50, iron deficiency anemia and the family history.

Call your local emergency number (112 in the EU, 999 in the UK, 911 in the US) for stomach pain that starts suddenly and is severe. The same applies to a lot of blood from your bottom, black sticky stool, or vomiting blood or vomit that looks green or like ground coffee. Not being able to pass stool or wind at all, struggling to breathe, and sudden chest pain or pressure also need an emergency call. Do not wait for it to pass. Emergency signs for pelvic pain are in the endometriosis post above. Sam replaces neither an emergency call nor an examination.

Log gut days and your period in Sam and see them in one calendar

You bring gut days and bleeding days across several cycles instead of "it's always bad before my period".

• Instead of separate notes: bleeding goes into cycle tracking, cramps or bloating into the same sheet; "More symptoms" sets mild, moderate or severe.
• Instead of typing in old periods: once you allow access, Sam brings in up to two years from Apple Health and never overwrites your entries.
• Instead of tally marks: the month calendar in Health History shows symptom days and period days as dots, not which symptom; the Cycle report and monthly report come as PDFs.

Sam keeps no stool type or stool count, cycle tracking and the symptom diary have no free-text note field, and the calendar, statistics and reports calculate no link. The monthly report has requirements, listed above. More on the IBS page.

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Sam is a wellness companion, not a medical device. The app does not diagnose, treat, cure or prevent any condition or health state. Always consult qualified professionals for medical decisions.

Related reading

• IBS and your doctor: what to write down
• What kind of doctor for IBS? Colonoscopy and blood tests
• Endometriosis: prepare your symptoms for the doctor
• Menopause symptom diary: what to track and for how long
• Seizures and your menstrual cycle: what to track

Sources

Updated: October 2026

• Adeyemo MA, Spiegel BM, Chang L: Meta-analysis: do irritable bowel syndrome symptoms vary between men and women? Aliment Pharmacol Ther 2010;32(6):738-755
• Meleine M, Matricon J: Gender-related differences in irritable bowel syndrome: potential mechanisms of sex hormones. World J Gastroenterol 2014;20(22):6725-6743
• Bernstein MT et al.: Gastrointestinal symptoms before and during menses in healthy women. BMC Womens Health 2014;14:14
• ESHRE Endometriosis Guideline Group: ESHRE guideline: endometriosis. Human Reproduction Open 2022(2):hoac009, chapter on diagnosis
• NHS: Endometriosis (reviewed 27 August 2024)
• NHS: Symptoms of menopause and perimenopause (reviewed 19 May 2026)
• NHS: Irritable bowel syndrome (IBS) - Symptoms (reviewed 17 March 2025)
• NHS: Stomach ache (reviewed 20 October 2026) and Chest pain (reviewed 8 August 2023)
• Arnold MJ: Summary of the AGA guideline on irritable bowel syndrome. Am Fam Physician 2023;108(5):527-529, Table 1
• DGVS and DGNM: S3 guideline on irritable bowel syndrome, 2021 update (PDF). Layer P et al., Z Gastroenterol 2021;59:1323-1415, AWMF 021-016 (as of June 2021, being updated per DGVS; in German), section a13 (p. 1341), tables 3-2 and 3-3 (pp. 1346 and 1348)
• IQWiG (gesundheitsinformation.de, in German): Regelschmerzen (period pain) (updated 22 March 2023), Prämenstruelles Syndrom (PMS) (updated 6 April 2022), Endometriose (updated 18 December 2024), Reizdarmsyndrom (updated 22 February 2023)