Despite differences across the world and within the US population, the middle menarche age remained relatively constant among well-nourished populations in developed countries – between 12 and 13 years. Environmental factors such as socioeconomic conditions, nutrition, and access to preventive health services can affect the timing and progression of adolescence. Some medical conditions can cause abnormal uterine bleeding characterized by unpredictable timing and variable amount of flow. Clinicians should educate girls and their caregivers (eg parents or guardians) about what to expect from the first menstrual period and the normal cycle length range of the next periods. Identifying abnormal menstrual patterns in adolescence can improve early detection of potential health problems for adulthood. It is important for clinicians to understand the menstrual cycle of adolescent girls, to distinguish between normal and abnormal periods, and to know how to evaluate the adolescent girl patient. By including an assessment of the menstrual cycle as an additional vital sign, clinicians reinforce its importance in assessing overall health for patients and caregivers.
Based on the following information, the American College of Obstetricians and Gynecologists provides these results and recommendations:
Clinicians should educate girls and their caregivers (eg parents or guardians) about what to expect from the first menstrual period and the normal cycle length range of the next periods.
When girls begin menstruating, clinicians should ask about the first day of the patient’s last menstrual period and their period at each preventive care or comprehensive visit.
Identifying abnormal menstrual patterns in adolescence can improve early identification of potential health problems for adulthood.
It is important for clinicians to understand adolescent girls’ menstrual patterns, to distinguish between normal and abnormal menstruation, and to know how to evaluate adolescent girls.
Teenage girls and their caregivers (eg parents or guardians) often have difficulty assessing what constitutes normal menstrual cycles or bleeding patterns. Patients and their caregivers may not be familiar with what is normal, and patients may not be able to inform their caregivers about menstrual irregularities or missed periods. In addition, although the patient may trust another adult they trust, the patient is often reluctant to discuss this issue with a caregiver. Some adolescent girls may seek medical attention for cycle variations that actually remain within the normal range, or may not be aware that their bleeding patterns are abnormal, and long-term health consequences can be attributed to major medical problems with potential.
Clinicians may also be unsure about the normal intervals for menstrual cycle length and the amount of menstrual bleeding during puberty. Clinicians who are confident that they understand early menstrual bleeding patterns will be able to convey information to their patients more frequently and with less guidance; Girls who have been trained in menarche and early periods will experience less anxiety when it occurs.
By including an assessment of the menstrual cycle as an additional vital sign, clinicians reinforce its importance in assessing overall health for patients and caregivers. While abnormal blood pressure, heart rate or respiratory rate can be key to diagnosing potentially serious health conditions, identifying abnormal menstrual patterns in adolescence can improve early identification of potential health problems for adulthood.
Normal Menstrual Cycles
Despite differences around the world and within the U.S. population, the middle menarche age remained relatively constant (between 12 and 13 years) in well-nourished populations in developed countries.
. The U.S. National Health and Nutrition Examination Survey has not found any significant change in median age in menarche over the past 30 years, with the exception of the non-Hispanic black population, whose average age is 5.5 months earlier than 30 years ago.
. Studies have shown that a higher gain in body mass index during childhood is associated with the early onset of puberty. This may be due to reaching the minimum required body mass index at a younger age. Environmental factors such as socioeconomic conditions, nutrition, and access to preventive health services can affect the timing and progression of adolescence.
Normal Menstrual Cycles in Adolescent Girls
Menarche (median age): 12.43 years
Average cycle interval: 32.2 days in the first gynecological year
Menstrual cycle range: Typically 21-45 days
Menstrual flow length: 7 days or less
Use of menstrual products: Three to six pads or tampons a day
Menarche typically occurs 2-3 years after telarche (breast budding) in Tanner stage IV breast development and is rare before Tanner stage III development.
. By age 15, 98% of women will have had menarche
. Not reached the menarche level by the age of 15 or for 3 years after the alarm
Assessment for primary amenorrhea should be considered for any adolescent who has not arrived. The absence of breast development until the age of 13 should also be evaluated.
Cycle Length and Ovulation
Menstrual cycles are irregular, especially during puberty, especially during the time from the first cycle to the second cycle. Most women bleed for 2–7 days in their first period
. The immaturity of the hypothalamic-pituitary-ovarian axis in the first years after menarche often results in anovulation and cycles may be somewhat longer; however, 90% of the cycles will be in the 21-45 day range
Short cycles shorter than 20 days and long cycles longer than 45 days can occur. In the third year after menarche, 60-80% of menstrual cycles last 21-34 days, as in adults.
Abnormal Uterine Bleeding
Some medical conditions can cause abnormal uterine bleeding characterized by unpredictable timing and variable amount of flow. Although a long interval between cycles is common due to anovulation during adolescence, it is statistically rare for girls and adolescents to remain amenorrheic for more than 3 months or 90 days (95th percentile for cycle length). Girls and adolescents with more than 3 months between periods should be evaluated. Although experts typically report that the average blood loss per menstrual period is 30 mL per cycle and chronic loss of more than 80 mL is associated with anemia, this has limited clinical use because most women cannot measure blood loss. Menstrual flow that requires changing one product every 1-2 hours is considered excessive,
Abnormal uterine bleeding can be caused by ovulation dysfunction, and bleeding patterns can range from amenorrhea to irregular heavy menstrual bleeding. Although ovulatory dysfunction is somewhat physiological in the first few years after menarche, it may be associated with endocrinopathies due to mental stress and eating disorders, as well as hypothalamic-pituitary-ovarian axis disorders such as polycystic ovary syndrome and thyroid disease.
. It has been commonly associated with heavy menstrual bleeding associated with anovulation, coagulopathy (including von Willebrand disease, platelet dysfunction and other bleeding disorders) or other serious problems (including liver failure), and rarely with a diagnosis of malignancy.
For a list of possible causes of abnormal uterine bleeding in adolescents. Even if the history suggests that the patient is not sexually active, diagnosis of pregnancy, sexual trauma and sexually transmitted infections should be excluded.
Causes of Abnormal Uterine Bleeding in Adolescent Girls
Immature hypothalamic-pituitary-ovarian axis
Hyperandrogenic anovulation (eg polycystic ovary syndrome, congenital adrenal hyperplasia or androgen producing tumors) *
Coagulopathy (eg von Willebrand disease, platelet dysfunction, other bleeding disorders or liver failure) †
Hypothalamic dysfunction (eg eating disorders [obesity, poor weight or significantly rapid weight loss] or stress-related hypothalamic dysfunction)
Primary pituitary disease
Primary ovarian failure
Iatrogenic (eg secondary to radiation or chemotherapy)
Medicines (eg hormonal contraception or anticoagulation therapy)
Sexually transmitted infections (eg cervicitis)
Malignancy (eg estrogen-producing ovarian tumors, androgen-producing tumors or rhabdomyosarcoma)
Clinicians should include adolescent development in their forward-looking guidance for children and caregivers, starting with 7-year and 8-year visits.
. Clinicians must take a continuous history and perform a full yearly examination, including examination of the external genitalia.
It is important to educate girls and their caregivers about the normal progression of puberty and the development of the menstrual cycle. Clinicians should convey that women will start menstruating approximately 2–3 years after breast development begins. Adolescent girls should understand that menstruation is a normal part of development and be informed about the use of feminine products and what is considered normal menstrual flow. It is preferred that caregivers and clinicians participate in this training process.
Preventive health visits should begin during adolescence to initiate a dialogue and create an environment where the patient can feel good about taking responsibility for their reproductive health and be confident that their concerns will be addressed in a confidential environment.
. As menarche is a very important milestone in physical development, clinicians should educate adolescent girls and their caregivers about what to expect from the first menstrual period and the normal cycle length range of subsequent periods. After adolescent girls begin menstruating, clinicians should ask about the first day of the patient’s last menstrual period and their menstrual pattern at each preventive care or comprehensive visit. By adding this information along with other vital signs in the Systems Review and Current Disease History, clinicians highlight the important role of menstrual patterns in reflecting overall health status.
Asking the patient to schedule their periods can be helpful, especially if the menstrual history is very uncertain or thought to be wrong. The importance of the correct schedule should be emphasized and the patient should be educated about what might be considered an abnormal menstrual cycle. Clinicians should explain that the length of the cycle from the first day of the menstrual period to the first day after the first day is counted and can vary by cycle, as this often leads to miscommunication between patients and clinicians. The use of technology can make it easier to create graphics; There are a number of easy-to-use smartphone apps designed for this purpose.
It is important for clinicians to understand adolescent girls’ menstrual patterns, to distinguish between normal and abnormal menstruation, and to know how to evaluate adolescent girls. Menstrual anomalies suggesting further evaluation are listed below.
Menstrual Abnormalities That May Require Evaluation
Has not started within 3 years
Did not start with symptoms of hirsutism at the age of 14
Not started with a history or examination suggestive of excessive exercise or eating disorder at the age of 14
Did not start at the age of 15
Occurs every 21 days or less frequently than 45 days
occurs 90 days apart, even for one cycle
Lasts more than 7 days requires frequent pad or tampon change (multiple soaking in 1-2 hours) is severe and is associated with a history of excessive bruising or bleeding, or a family history of bleeding disorder