The AUB medical abbreviation stands for abnormal uterine bleeding, a broad label for bleeding from the uterus that is unusual in how often it comes, how long it lasts, how heavy it is, or when it happens. It names a pattern rather than a final diagnosis, so a note that says AUB usually goes on to name a likely cause or a plan to find one.
You will see it in gynecology and primary care visit notes, ultrasound orders, patient portal summaries and referral letters. It often sits near LMP, the last menstrual period, and lab orders such as a CBC to look for blood loss. This page explains what clinicians mean by it, how the cause is sorted, and how to decode it in chart notes.
At a glance
Stands for
Abnormal uterine bleedingUsed in
Gynecology, primary care, emergency care, ultrasound reportsOlder wording
Dysfunctional uterine bleeding (DUB) and menorrhagia, now used lessCause system
PALM-COEIN, nine groups of possible causesForms
AUB, AUB-L (fibroids), AUB-O (ovulatory), acute or chronic AUBDo not confuse with
AUD, alcohol use disorder, one letter apart
What the AUB medical abbreviation describes
Clinicians use AUB when bleeding from the uterus falls outside the usual pattern for that person. A typical cycle is often described as coming roughly every 24 to 38 days and lasting up to about 8 days, but what counts as unusual also depends on age, pregnancy status, and how the bleeding affects daily life. Heavy flow that soaks through pads quickly, bleeding between periods, bleeding after sex, and very irregular cycles can all be grouped under this label.
Bleeding after menopause is usually written separately as postmenopausal bleeding, because it is handled with its own set of checks. Bleeding in pregnancy is also a separate topic. AUB mainly refers to people of reproductive age who are not pregnant.
How the causes are sorted: PALM-COEIN
Gynecology groups the reasons for AUB into a memory aid called PALM-COEIN. The first four letters are structural causes that can often be seen on imaging or with a biopsy. The last five are causes that do not show up as a structure.
| Letter | Group | Plain meaning |
|---|---|---|
| P | Polyp | Small growth in the uterine lining |
| A | Adenomyosis | Lining tissue growing into the uterine muscle |
| L | Leiomyoma | Fibroid, a noncancerous muscle growth |
| M | Malignancy or hyperplasia | Cancer or thickened, precancerous lining |
| C | Coagulopathy | A bleeding or clotting disorder |
| O | Ovulatory dysfunction | Irregular or absent ovulation |
| E | Endometrial | A problem within the lining itself |
| I | Iatrogenic | Caused by a medicine or device |
| N | Not yet classified | Rare causes that fit no other group |
A note may add the letter as a suffix, such as AUB-L for bleeding linked to fibroids or AUB-O for ovulatory causes.
Reading AUB in a chart note
An assessment line often pairs the label with the suspected group and the next steps. The sample assessment at the top of this page, for example, says the clinician thinks irregular ovulation is the likely reason and wants a blood count and a thyroid test.
Referral letter: "32 yo G0 with chronic AUB, heavy menses x 6 mo, Hgb 10.2, TVUS shows 3 cm intramural fibroid." Read in plain words: a 32 year old who has never been pregnant has had heavy periods for six months, her hemoglobin is a little low, and a transvaginal ultrasound found a fibroid in the uterine wall. The writer is pointing toward the L group.
Acute AUB means a sudden heavy episode that may need prompt care. Chronic AUB means the pattern has been present for most of the past six months.
Tests that often follow an AUB entry
Because AUB is a starting point, the plan section usually lists ways to narrow it down. Common choices include a pregnancy test, a complete blood count to check for anemia, thyroid tests, and a pelvic or transvaginal ultrasound. Depending on age and risk, a sample of the uterine lining may be taken. When heavy bleeding has been present since the first periods, clotting tests may be added to look for a bleeding disorder.
Every lab sets and prints its own normal limits, so a hemoglobin or thyroid value makes sense only beside the limits on that same sheet.
Talking it over at your next gynecology visit
If you see AUB in your own record, it can help to ask which PALM-COEIN group your clinician suspects, which tests are planned, and what each result would change. You might also check whether your blood count shows anemia and what the options are for managing heavy or irregular bleeding while the cause is being worked out.
This page explains a chart label in general terms. Your own gynecologist, nurse practitioner or family doctor knows your history and can say how this label fits your situation.
Frequently asked questions
What does AUB stand for in a medical note?
AUB stands for abnormal uterine bleeding. It covers bleeding from the uterus that is unusual in timing, length, amount or regularity, and it is usually followed by a likely cause or a testing plan.
Is AUB the same as a heavy period?
Not exactly. Heavy menstrual bleeding is one kind of AUB, but the label also covers bleeding between periods, very frequent or very infrequent cycles, and bleeding after sex.
What does AUB-O mean?
AUB-O means abnormal uterine bleeding linked to ovulatory dysfunction, where ovulation is irregular or absent. It is one of the nine groups in the PALM-COEIN system.
Why did doctors stop saying DUB?
Dysfunctional uterine bleeding was a vague term that meant different things to different people. The newer AUB system names the suspected cause with a letter, which makes notes clearer and easier to compare.
Does AUB mean cancer?
No. Most AUB has noncancerous causes such as fibroids, polyps or irregular ovulation. Malignancy is one group in the system, which is why some people are offered a lining biopsy as part of the workup.