Spotting is a very light form of bleeding that occurs outside of your regular menstrual cycle. It can occur mid-cycle, before or after your period, or during menopause. It may even occur during pregnancy for some women.

You may notice spotting by seeing a few drops of red or brown on your underwear or on toilet paper after using the bathroom. Spotting may occur sporadically throughout the month, or you may have daily spotting. Spotting doesn’t produce enough blood to fill up a sanitary pad.

There are many causes of spotting and other types of abnormal uterine bleeding. The causes can range in severity and may result in a variety of treatment outcomes.

You should discuss spotting that occurs regularly or lasts for an extended period of time with your doctor.

Read on to learn why you may have spotting for a month, and when to seek help from a doctor.

Hormonal changes can cause spotting. You may experience spotting if you’re starting puberty and just getting your period or if you’re entering menopause and nearing the end of your menstrual cycles. Puberty typically begins between the ages of 10 and 14. Perimenopause often starts between ages 45 and 55.

During puberty, your hormones are constantly adjusting and your menstrual cycle can be irregular. During perimenopause, the lining of your uterus may thicken, resulting in spotting or irregular bleeding.

There are several reasons you may experience lengthy spotting if you use hormonal contraception. Some types of hormonal contraception include:

You may experience spotting when you begin using birth control pills or have a birth control injection or implant inserted by your doctor. Nearly 30 percent of women experience abnormal bleeding during the first month of taking birth control pills.

About 70 percent of women with an injectable and 80 percent of women with an implant experience abnormal bleeding in the first year. This type of should go away as your body adjusts to the hormones.

You may also experience spotting if you forget to take your birth control pills on a regular basis.

Polycystic ovary syndrome (PCOS) is caused by hormonal imbalances. It can lead to irregularities with your periods.

Some symptoms of PCOS include:

  • cysts that grow on your ovaries
  • hair growth on the body, including facial hair
  • acne
  • thinning hair on the scalp
  • difficulty with weight management

Endometriosis occurs when your body produces uterine tissue in other places in your reproductive system, such as your ovaries and fallopian tubes. Your body can’t remove this unwanted tissue, which can lead to complications.

Some symptoms of endometriosis aside from spotting or irregular bleeding include pain:

  • in your pelvis
  • during your period
  • during sex
  • when using the bathroom

Long-term spotting could be the result of fibroids or polyps. Fibroids occur on the uterus and are the result of overgrowing muscles. Polyps are overgrowths that occur in the uterus or cervix.

Both of these conditions are benign, but they can cause discomfort when you urinate as well as cause irregular bleeding.

STIs can cause long-term spotting. You’re susceptible to an STI if you’re sexually active. You’re also at higher risk for contracting an STI if you have unprotected sex.

Some STIs that can cause spotting or bleeding between your periods include chlamydia and gonorrhea.

Human papillomavirus (HPV) is another STI that can cause spotting or bleeding after sex. If you engage in frequent sexual activity, this could result in regular and extended spotting.

See a doctor if you suspect you may have an STI.

STIs or other bacteria may spread to your reproductive system and cause pelvic inflammatory disease (PID). This could result in spotting.

Other symptoms of PID include:

  • abdominal pain
  • unusual or foul-smelling vaginal discharge
  • pain when urinating

There is a chance long-term spotting is a sign of a more serious condition, such as cancer. Some risk factors for cancers related to spotting include:

  • family history
  • age
  • obesity
  • history of past pregnancies

It’s not unusual to experience spotting during pregnancy. When it occurs, the amount of time it lasts and any other associated symptoms could signal complications.

The March of Dimes states that up to 50 percent of pregnant women experience bleeding or spotting.

It’s more common to experience spotting during the first trimester of pregnancy. Two reasons you may have spotting during the first trimester are:

  • implantation bleeding, which is when a fertilized egg attaches to your uterine lining a few weeks after fertilization
  • an increased number of blood vessels in your cervix, which may cause spotting after sex or during a pelvic examination; this may continue into later months of pregnancy as well

Spotting that occurs in the second and third trimesters could be caused by serious conditions such as:

Contact your doctor if you experience more than 24 hours of spotting during your first trimester or any spotting in your second and third trimesters.

Call your doctor right away if your spotting gets heavier or you have other concerning symptoms such as abdominal pain, cramping, or dizziness.

Bleeding in early pregnancy may be the sign of a miscarriage or ectopic pregnancy. Bleeding in later pregnancy may be the sign of a serious condition that needs medical attention.

Talk to your doctor if you have prolonged spotting. You may find out that this spotting isn’t serious, but if it’s caused by an underlying condition, it’s important to find out the cause and if there’s anything you can do to treat it.

Contact your doctor right away if you experience spotting after menopause, when you’re 8 years old or younger with no signs of puberty, or if you’re pregnant.

Prolonged spotting could be caused by one of many conditions. Your doctor could perform a range of tests and procedures to diagnose your condition. These include:

Spotting may be treated in a variety of ways, depending on the cause. Your doctor may recommend that you try birth control pills to regulate your hormones. They may prescribe antibiotics if you have an infection or a medication to treat fibroids, for example. In some cases, you may need surgery.

Your doctor will give you the best advice for managing long-term spotting. You may wish to wear low-flow sanitary pads, though there shouldn’t be enough blood to soak through a pad.

Your doctor may recommend that you change your diet or take supplements to make up for iron deficiencies caused by blood loss.

Occasional spotting between periods shouldn’t be a cause for concern unless you’re prepubescent, pregnant, or postmenopausal.

However, long-term spotting that lasts a month or longer should be discussed with a doctor. Your doctor can determine the cause of your spotting and recommend a treatment plan to reduce spotting and other symptoms.