Bleeding Between Periods: What You Need to Know


Unusual bleeding between periods can be called spotting, intermenstrual bleeding and metrorrhagia. While it’s not an uncommon experience, there’s also a wide variety of reasons abnormal vaginal bleeding may occur.

Many of these reasons are not concerning, so don’t jump to anxious conclusions if this is happening to you. However, it’s worth understanding what might explain any bleeding you’re experiencing. This will help you determine whether to seek help.

First, though, let’s take a moment to distinguish unusual or abnormal vaginal bleeding from your regular period or menses.

Understanding Bleeding Between Periods

Monthly menses typically includes lighter and heavier days. Some describe the lighter days at the start or end of their period as spotting. However, although it can be difficult to tell the difference, menstruation and non-period bleeding are different.

In general, spotting is any kind of light bleeding that occurs outside of menstrual bleeding (i.e. the shedding of the lining of the uterus). While spotting has a lot of different causes (see below), it is generally lighter and does not require more than a panty liner or a pair of Leakproof Underwear. 

If you experience heavy bleeding that is not your period, you should seek immediate medical care. Here’s an overview to help you tell the difference:

Common Causes of Bleeding Between Periods

This next section might prove a little overwhelming. The truth is there are many possible explanations of bleeding between periods. Some of these you’ll be able to rule out on your own (e.g. if you’re not on medication or know you're not pregnant). But others will require a doctor’s visit. 

This list is not exhaustive, but these are the most common causes of bleeding between periods.

Birth Control Causes

  • Birth Control: According to Medical News Today, bleeding often occurs in the first 6 months of taking a new birth control pill. Doctors sometimes refer to this as breakthrough bleeding.
  • Morning-After Pill: According to the Mayo Clinic, the morning-after pill can cause bleeding between periods or heavier menstrual bleeding.
  • Intrauterine Device (IUD): Some women with an IUD for birth control may also experience non-period bleeding.

External Causes

  • Trauma or Medical Examination: If you’ve experienced rough sex or a medical exam like a Pap test, you may experience vaginal bleeding.
  • Medications: Certain medications may cause abnormal vaginal bleeding. Your pharmacist should advise you of any side-effects of medication.
  • Stress: Stress can trigger many reactions.

Common Infections

The following infections can cause spotting between periods. It’s worth noting that most infections are treatable. However, infections can become more serious if ignored.

  • Sexually Transmitted Infection (STI), including chlamydia, gonorrhea, and genital warts.
  • Pelvic Inflammatory Disease (PID), an infection of the upper part of the female reproductive system.

Pregnancy-Related Causes

  • Ovulation: When the ovaries release the egg, a tiny follicle ruptures to allow the egg to be released. This can be a cause of bleeding for a day or so.
  • Implantation bleeding: After a sperm fertilizes an egg, the egg implants in the womb. Sometimes, implantation causes light bleeding known as implantation bleeding.
  • Ectopic Pregnancy: Signs and symptoms of an ectopic pregnancy include abdominal pain and vaginal bleeding.
  • Pregnancy: According to the American Pregnancy Association, 20% of women experience spotting during the first 12 weeks of being pregnant.
  • Miscarriage: Heavy spotting is one of the symptoms of miscarriage.
  • Breastfeeding: Depending on the frequency of breastfeeding and your own individual hormones, spotting may occur before full periods return.

Other Causes

  • Fibroids or Polyps: These benign tumours can cause irregular or heavy periods and vaginal bleeding between periods.
  • Endometriosis: According to the Mayo Clinic, women with endometriosis may experience occasional heavy menstrual periods or bleeding between periods (intermenstrual bleeding).
  • Polycystic ovary syndrome (PCOS): PCOS can cause cysts in the ovaries and make it difficult to get pregnant. It can also cause irregular vaginal bleeding.
  • Blood clotting disorders, like von Willebrand disease.
  • Other health conditions, like hypothyroidism, liver disease, or chronic kidney disease.
  • Cancer: Cancer or pre-cancer of the cervix, uterus, or (very rarely) fallopian tubes can cause spotting or abnormal bleeding.

Perimenopause & Menopause

  • Perimenopause: The time before menopause is known as perimenopause. During perimenopause, hormones fluctuate greatly. These hormonal shifts can have an effect on ovulation and your entire menstrual cycle. Some women notice irregular or skipped periods and abnormal bleeding between periods during perimenopause. 
  • Vaginal dryness, especially due to lack of estrogen after menopause, can cause bleeding.
  • Cancer: According to the Dana-Farber Cancer Institute, spotting in post-menopausal women can, in some cases, be an early sign of cancer and should always be investigated further.

When to Seek Medical Help

If you experience vaginal bleeding outside your period that is heavy (requiring a tampon or pad), we advise seeking medical advice.

If you’re experiencing light spotting but no other symptoms or pain, we recommend monitoring your cycle by keeping a period diary. You may find it occurs on a regular cycle (e.g. during ovulation). 

If bleeding is is accompanied by any of the following symptoms, it warrants a trip to the doctor:

  • Heavy periods with a lot of clotting.
  • Irregular periods.
  • Abdominal pain or cramping.
  • Pain or a burning sensation when peeing.
  • Unusual vaginal discharge and/or redness and itchiness.

Even if you don’t have any of the above symptoms, don’t ever ignore abnormal vaginal bleeding or abnormal uterine bleeding in the following situations:

  • If you think you’re pregnant: You should always see a doctor as soon as you think you may be pregnant to be administered a pregnancy test.
  • When it happens inconsistently: If spotting seems to happen frequently and randomly, you should definitely look into it.
  • It begins after unprotected sex: Unprotected sex can put you at risk for STIs and other infections so if you notice spotting after unprotected sex, it’s wise to visit a doctor.
  • You are on medication that may cause spotting: If spotting can be a side-effect of any medication you are on, you should seek out professional help.
  • Spotting occurs post-menopause: It is never considered normal for anybody post-menopause to experience spotting or vaginal bleeding.

If you're at all anxious or losing sleep over any experience related to your health, it's always worth checking with a medical professional. Even if they simply reassure you that there's nothing to worry about, you'll be able to move on from fear and anxiety. 

And if there is a cause for concern, you'll be glad you investigated it early so that you can move through the steps of diagnosis and treatment with your doctor!