Common Reasons for Abnormal Bleeding in Teenagers

This post was written by Sarah Cox, a third year medical student at UTHSCSA studying to become an OBGYN. 

Do you want to learn more about common reasons for abnormal bleeding in teenagers? Here are some of the most common reasons: 

Developmental (most common): 

During the first 2-3 years after starting your period, your body is still undergoing puberty development of the brain-ovary-uterus connections. As a result, having irregular period intervals, duration, and bleeding during this time is expected, and these periods can be infrequent and rather heavy. The abnormal bleeding in these cases do resolve with time and typically don’t need treatment. However, if your bleeding is more than 1 pad per hour or interfering with daily activities, you have reason to seek out a doctor

The “Female Athlete Triad”: 

Not having periods or having irregular, infrequent periods in teens with uteruses that are not eating enough for their activity level can be a sign of the “female athlete triad.” This is a term used to describe the brain’s response to body stress by not having enough nutrients, causing the hormones needed to have periods to decrease. Stress fractures and overuse injuries are also common in this population. Those at risk include teens that play sports with emphasis on thinness, those who are dieting or have eating disorders, or feeling pressure to lose weight. Visiting the doctor can help with diagnosis and treatment. 

Bleeding Disorders: 

For some menstruators, heavy periods can be due to bleeding disorders, such as von Willebrand disease, platelet disorders, and blood coagulation disorders. Other signs can be frequent gum bleeding, frequent nose bleeds, and easy bruising. These bleeding disorders are often genetic, so ask your family members if anyone else has a bleeding disorder. Lab work and a doctor's visit can diagnose bleeding disorders. 

Medical Conditions: 

Other medical conditions can lead to irregular menstrual bleeding, including hypothyroidism (low thyroid output), hyperprolactinemia (too much of a hormone called prolactin), and Polycystic Ovary Syndrome (imbalance of certain reproductive hormones, often with symptoms of severe acne, facial hair growth, and weight gain). All of these conditions can be diagnosed by a doctor with lab work and sometimes an ultrasound. 


Sometimes infections such as chlamydia and gonorrhea (two of the most common sexually transmitted infections) can lead to a pelvic infection that has symptoms of fever, abnormal vaginal discharge, and pelvic pain, in addition to abnormal bleeding. There is no shame in having a sexually transmitted infection; these infections are very common and your doctor is happy to help you! Both infections are treated with prescription antibiotics. 

Birth Control: 

If you are on a form of birth control, your period bleeding could be increased, reduced, irregular, or absent, depending on the type. This is likely a normal side effect of the contraceptive method. For example, copper IUDs often cause increased bleeding, and hormonal IUDs, the Depo shot, Nexplanon, and birth control pills often cause decreased bleeding. 

Early Pregnancy Loss (Miscarriage): 

If it is possible that you are pregnant, heavy vaginal bleeding and cramping can be a sign of having a miscarriage. Going to the emergency room if your bleeding is very heavy and painful, or scheduling a doctor’s appointment if your bleeding is manageable, can lead to diagnosis and care. 

Are you wondering if what your are experiencing would be considered normal? You can read more here

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