Blood stains on your underwear when your period isn't due for another two weeks. Light bleeding after sex. Persistent brown discharge. These types of bleeding between periods, also called metrorrhagia or spotting depending on their amount, affect up to 30% of women at some point in their lives. Reassuring for some, alarming for others, these bleeding episodes can have dozens of different causes. Most are benign (change in contraception, ovulation, stress), but some warrant prompt medical attention. This article reviews all the possible causes of bleeding between periods, the warning signs to watch out for, and solutions to stop it when it becomes bothersome.
The main thing to remember
- On bleeding between periods affect up to 30% of women and often have benign causes.
- Le ovulation spotting (5% of women) is normal and occurs mid-cycle
- On hormonal contraceptives are the most frequent iatrogenic cause (25% of users in the first 3 months)
- Bleeding and intense pain require prompt consultation (ectopic pregnancy, ruptured cyst, infection)
- Le copper IUD may cause intermenstrual bleeding in the first few months
- After menopause, Any bleeding is abnormal and requires medical advice
- Hormonal treatments (the pill, progestins) can stop functional bleeding.
Unusual Bleeding: What Exactly Are We Talking About?
Before delving into the causes, let's clarify what we mean by "bleeding between periods". Not all vaginal bleeding is the same, and its medical name varies depending on its amount and duration.
Spotting vs. Metrorrhagia
Doctors distinguish between two main types of bleeding between periods, based on their intensity.
Spotting (light bleeding)
- Medical definition Light vaginal bleeding that does not require period protection (or just a panty liner)
- Aspect A few drops of blood, often pinkish, brown, or light red
- Duration Generally, a few hours to 2-3 days
- Frequency Very common, rarely a cause for concern
Metrorrhagia (heavy bleeding)
- Medical definition Significant vaginal bleeding occurring outside of menstruation
- Aspect Bright red bleeding requiring periodic protection
- Duration Variable, from a few days to several weeks
- Frequency Less common, deserves more medical attention
The PALM-COEIN Classification System
In medicine, the causes of abnormal uterine bleeding are classified according to the international PALM-COEIN system, adopted by the International Federation of Gynecology and Obstetrics (FIGO).
The Most Common Causes of Bleeding Between Periods
Let's review the most common reasons for intermenstrual bleeding, from the most benign to the most concerning.
1. Hormonal Contraception (Iatrogenic Cause)
This is the The number one cause of bleeding between periods In women of childbearing age using contraception, approximately 25% of pill users experience spotting during the first 3 months.
Contraceptive pill
- first 3 months Frequent spotting due to adaptation, generally benign
- Forgotten pill Sudden hormonal drop causing rupture bleeding
- Pill with too low a dose The endometrium is unstable and bleeds regularly
- Continuous pill After 3-4 consecutive birth control pills, the endometrium may bleed spontaneously.
- Drugs interactions Antibiotics and St. John's wort reduce effectiveness.
Hormonal IUD (Mirena, Kyleena, Jaydess)
- Spotting during the first 3-6 months Very frequent, usually transient
- Irregular bleeding May persist in some women
- After adaptation, 50% of women no longer have periods at all.
Copper IUD
- Intermenstrual bleeding in the first few months Related to local inflammation
- Heavier periods Known side effect of the copper IUD
- If bleeding persists beyond 6 months, consult a doctor to check the position.
2. Ovulation Spotting (Physiological)
Approximately 5% of women experience light bleeding around the time of ovulation, usually around day 14 of a 28-day cycle. This is a normal and harmless phenomenon.
How to recognize ovulation spotting
- Precise timing Occurs mid-cycle, approximately 12-16 days before the next period.
- Short duration From a few hours to a maximum of 1-2 days
- Color Pink, light red, or light brown
- Quantity Very light, just a few drops
- Associated to Abundant and clear cervical mucus, mild pain on one side (mittelschmerz)
- Recurrence Occurs at the same time each cycle
Mechanism: The sudden drop in estrogen just after ovulation and before the rise in progesterone can cause slight shedding of the endometrium.
3. Ovulation Disorders (Ovulatory Dysfunction)
Hormonal imbalances are the most common cause of abnormal gynecological bleeding, aside from contraception. When ovulation is delayed or absent, the endometrium becomes unstable and bleeds erratically.
- Polycystic ovary syndrome (PCOS) Irregular cycles with unpredictable bleeding
- severe stress Disrupts the hypothalamic-pituitary axis and delays ovulation
- Rapid weight loss or gain Temporary hormonal imbalance
- Intensive sport Suppresses ovulation in elite athletes
- Thyroid disorders Hypothyroidism or hyperthyroidism
- hyperprolactinemia Excess prolactin disrupts the cycle
4. Implantation Bleeding (Early Pregnancy)
About 25% of pregnant women experience light bleeding when the embryo implants in the uterus, usually 6-12 days after fertilization.
Characteristics of implantation bleeding
- Timing 7-10 days after ovulation, a few days before the expected date of menstruation
- Duration A few hours to a maximum of 2 days
- Color Light pink or brown
- Quantity Very lightweight, no protection required
- May be accompanied by mild cramps
5. Post-Coital Bleeding
Bleeding after sexual intercourse affects approximately 9% of women. The most common causes are benign but warrant investigation.
- Cervical ectropion (19-34%): Fragile cells of the cervix that bleed on contact
- Vaginal dryness (15-25%): Lack of lubrication causing microtrauma
- Cervical polyps (5-18%): Benign growths
- Infections Cervicitis, vaginitis
- Mechanical trauma : Penetration too rapid or too deep
6. Uterine Polyps and Fibroids
These benign tumors of the uterus are very common and can cause intermenstrual bleeding.
Uterine polyps Prevalence of 8-35%, increases with age. Often asymptomatic, but can cause light intermenstrual bleeding.
Fibroids (leiomyomas) Affecting 20-40% of women of reproductive age, submucosal fibroids (which distort the uterine cavity) cause heavy and irregular bleeding.
7. Coagulation Disorders
Approximately 20% of women experiencing heavy menstrual bleeding have an underlying clotting disorder. This proportion is even higher among adolescent girls.
- Von Willebrand disease The most common genetic bleeding disorder
- Platelet dysfunction
- Taking anticoagulants (aspirin, oral anticoagulants)
Unexpected bleeding? Protect yourself discreetly.
Period Panties are perfect for managing spotting and light bleeding between periods, without the discomfort of disposable panty liners.
Bleeding + Worrying Symptoms: When to Seek Emergency Medical Care
While bleeding between periods is often benign, certain combinations of symptoms require prompt, or even urgent, medical attention.
Bleeding + Intense Pelvic Pain
This association can report gynecological emergencies requiring immediate attention.
Possible urgent causes
- Ectopic pregnancy Severe pain on one side + bleeding + positive pregnancy test or missed period
- Ruptured ovarian cyst Sudden, sharp pain on one side, nausea, malaise
- Ovarian torsion Intense and sudden pain, vomiting
- Pelvic infection (salpingitis) Pain + fever + foul-smelling discharge
- Miscarriage in progress Heavy bleeding + intense cramps
If you experience these symptoms, call 15 or go to the emergency room.
Bleeding + Bloated Stomach
The combination of bleeding and an abnormally swollen abdomen can have several explanations.
- Premenstrual syndrome Bloating and spotting before menstruation (benign)
- Large uterine fibroid May cause abdominal bloating and bleeding
- Ascite Fluid accumulation in the abdomen (rare, requires further investigation)
- Large ovarian cyst : Sensation of heaviness
- Pregnancy If the stomach swells and there is light bleeding, take a test
Heavy Bleeding Outside of Menstruation
Very heavy bleeding requiring changing protection every 1-2 hours is abnormal and requires prompt medical attention.
Signs of acute uterine hemorrhage
- Bleeding requiring more than one pad/tampon per hour
- Large blood clots
- Dizziness, malaise, extreme fatigue (signs of anemia or shock)
- Paleness, rapid heart rate
- Bleeding that does not stop after 7 days
Irregular Bleeding According to Age and Situation
The causes of bleeding vary considerably depending on age and stages of reproductive life.
Adolescence and the Onset of Menstruation
Irregular cycles are the norm for the first 1-2 years after menstruation begins. Ovulation is often absent or irregular, resulting in unpredictable bleeding.
Normal during adolescence Cycles of 21 to 45 days, irregular bleeding, occasional spotting
To monitor Very heavy bleeding requiring more than one pad per hour (may indicate a clotting disorder)
Reproductive Age (20-45 Years)
This is the period when the causes are most varied. First consider contraception, pregnancy, then structural causes (polyps, fibroids).
Perimenopause (45-55 Years)
Menstrual cycles become irregular as menopause approaches. Hormone levels fluctuate, causing erratic bleeding.
- Normal in perimenopause Cycles that lengthen or shorten, occasional spotting
- To check Very heavy or prolonged bleeding (risk of endometrial hyperplasia)
- An assessment including ultrasound and endometrial biopsy is often recommended
After Menopause
It's simple, Any vaginal bleeding occurring more than 12 months after the last period is abnormal and requires prompt medical advice to rule out the possibility of endometrial cancer.
After menopause, even light spotting requires a pelvic ultrasound and often an endometrial biopsy to rule out cancer.
How to Stop Bleeding Between Periods?
Treatment depends entirely on the identified cause. Here are the most common medical approaches.
Hormonal Treatments
For bleeding related to hormonal imbalance or ovulatory dysfunction, hormones are the first-line treatment.
Non-Hormonal Medications
- Tranexamic acid An antifibrinolytic that reduces bleeding by 40-50%. Effective for heavy periods and spotting.
- Anti-inflammatory drugs (NSAIDs) Ibuprofen and naproxen reduce blood flow by 20-30%.
- Iron Supplement if anemia is due to prolonged bleeding
Surgical Treatments
Reserved for structural causes or failures of medical treatment.
- Polypectomy Hysteroscopy: Removal of polyps
- Myomectomy Surgical removal of fibroids
- Endometrial ablation Destruction of the endometrium (if pregnancy is not desired)
- Hysterectomy A final solution as a last resort
- Dilation and curettage (D&C) Endometrial scraping, temporary effect
Natural Solutions and Lifestyle
For light bleeding related to stress or a minor hormonal imbalance, some approaches may help.
- Stress management Meditation, yoga, sufficient sleep
- Balanced diet Avoid restrictive diets
- Stable weight Sudden changes disrupt hormones
- Reduce intensive exercise If you are an athlete
- Iron and vitamin C To prevent anemia
Important: These measures help for mild functional causes, but do not replace medical treatment if bleeding persists or worsens.
Diagnosis: What Tests Are Needed to Identify the Cause?
If you experience persistent or worrying bleeding outside of your period, your doctor will proceed step by step to identify the cause.
Interview and Clinical Examination
The doctor will ask you detailed questions about your bleeding, your cycle, your contraception, your medical and family history.
Initial Examinations
- Pregnancy test Systematic for all women of childbearing age
- Blood count : Anemia screening
- Hormonal assessment TSH (thyroid), prolactin, LH, FSH, estrogen, progesterone
- Coagulation assessment : If very heavy bleeding or a history of bleeding
- Pelvic ultrasound : Visualizes the uterus, ovaries, and endometrial thickness
Second Intention Examinations
- Hysteroscopy Camera inside the uterus to visualize polyps, fibroids, abnormalities
- Endometrial biopsy Tissue sampling for analysis (cancer, hyperplasia)
- Pelvic MRI To characterize fibroids, adenomyosis
- Hysterosonography Ultrasound with injection of saline solution into the uterus
When to Consult a Doctor for Bleeding Outside of Menstruation?
Not all bleeding outside of menstruation requires an emergency consultation, but certain warning signs should not be ignored.
Consult an emergency service (15 or emergency room)
- Very heavy bleeding (more than one pad per hour for several hours)
- Severe pelvic or abdominal pain
- Malaise, dizziness, fainting
- Fever + bleeding + pain (suspected infection)
- Positive pregnancy test + bleeding + pain (suspected ectopic pregnancy)
Consultation within 48-72 hours
- Repeated bleeding between periods over several cycles
- Bleeding that lasts more than 7 days
- Recurrent post-coital bleeding
- Bleeding + extreme fatigue (suspected anemia)
- Any bleeding after the menopause
Possible observation
- Light spotting for 1-2 days mid-cycle (probable ovulation)
- Spotting during the first 3 months of a new contraceptive
- Light and single spotting after a report
- Minor bleeding that occurred once without any other symptoms
But if this happens again, consult a doctor to identify the cause.
You Are Not Alone in the Face of Irregular Bleeding
Nearly one in three women will experience bleeding between periods at some point in their lives. If this happens to you, know that the vast majority of causes are benign and perfectly treatable. This bleeding can be unsettling, especially when you don't understand its origin, but your body isn't "broken" by it. Whether it's a hormonal adjustment, stress, ovulation spotting, or a side effect of your contraception, most of the time there's a reassuring explanation.
Trust your instincts. If these bleeding episodes are accompanied by intense pain, become very heavy, or recur without a clear explanation, consult a doctor without feeling guilty. Keeping a simple menstrual calendar can help you identify a pattern and facilitate communication with your doctor. You deserve to be heard, understood, and supported in finding solutions tailored to your situation.
Sources & Scientific References
This article is based on published scientific studies and international recommendations.
Studies on abnormal uterine bleeding
- Munro MG, et al. (2018). FIGO classification system (PALM-COEIN) for causes of abnormal uterine bleeding. International Journal of Gynecology and Obstetrics. DOI: 10.1016/j.ijgo.2010.11.011
- Davis E, Sparzak PB. (2025). Abnormal Uterine Bleeding. Stat Pearls. NCBI Bookshelf
- Whitaker L, Critchley HO. (2016). Abnormal uterine bleeding. Best Practice & Research Clinical Obstetrics & Gynaecology. DOI: 10.1016/j.bpobgyn.2015.11.012
- Maybin JA, Critchley HO. (2022). Uterine bleeding: how understanding endometrial physiology underpins menstrual health. Nature Reviews Endocrinology. DOI: 10.1038/s41574-021-00629-4
Studies on ovulation and intermenstrual spotting
- Crawford NM, Steiner AZ. (2015). A prospective evaluation of the impact of intermenstrual bleeding on natural fertility. Fertility and Sterility. PMC4853238
- Reed BG, Carr BR. (2018). The Normal Menstrual Cycle and the Control of Ovulation. Endotext. NBK279054
International recommendations
- American College of Obstetricians and Gynecologists. (2013). Management of Acute Abnormal Uterine Bleeding in Nonpregnant Reproductive-Aged Women. Committee Opinion No. 557. ACOG
- Sweet MG, et al. (2019). Abnormal Uterine Bleeding in Premenopausal Women. American Family Physician. AAFP extension
- Ameli (Health Insurance). Bleeding between periods or very heavy, long periods: what are the causes? Ameli Link
- High Authority of Health (HAS). (2022). Heavy uterine bleeding in young women with rare or acquired bleeding disorders. Ameli Link
Note: The links provide direct access to scientific publications and official recommendations.
Medical Warning: This article is for informational purposes only and is not a substitute for professional medical advice. In case of heavy bleeding, severe pain, or any other concerning symptoms, consult a doctor, gynecologist, or midwife immediately.
