Menstria · menarche
Is she on track?
Puberty runs on a wide schedule, and most of what looks alarming is ordinary. But a short list of findings genuinely should not wait — and they are the ones most often waved through, because everyone expects the early years to be irregular anyway.
This checks pubertal progress and early cycles against the criteria a clinician uses, and tells you which of four situations you are in.
Stop and get help now — do not finish this — if any of these apply:
Monthly lower abdominal pain that comes and goes in a cycle, with no bleeding ever having happened. Severe pelvic pain with difficulty passing urine. Soaking through a pad or tampon every hour for two hours in a row. Feeling faint, dizzy or breathless with bleeding. New headaches with vision changes or seizures alongside early breast development.
What this does
It applies the ACOG adolescent thresholds — which are deliberately wider than the adult ones — rather than judging a 13-year-old against adult reference ranges. It handles three questions: whether puberty has started too early, whether periods are late in arriving, and whether the cycles that have started look the way early cycles are supposed to look.
Nothing you enter leaves your browser.
One honest limitation, stated up front
This tool asks whether breast development has started and roughly when. It does not ask you to grade it, because grading it from the outside does not work: when girls rated their own breast stage against a blinded physician examination, only about 45% were correct, and accuracy drops further with higher body weight. Parents do somewhat better on the simple started-or-not question than on grading.
So the timing answers here carry real uncertainty, and the tool is built to tolerate that. It errs toward suggesting a conversation rather than toward reassurance. A hands-on examination answers in two minutes what no questionnaire can.
Step 1
Which describes her?
Periods not started
Pubertal progress
Urgent features
Tick anything that is true.
Age and development
Even a small firm lump under the nipple counts. This is the first sign of puberty, and it usually comes well before any bleeding.
Breast budding, Tanner B2 or beyond. Self- and parent-reported staging is unreliable; only the binary is used here.
Other findings
Tick anything that applies.
Periods have started
Are these cycles normal?
Early cycles are supposed to be irregular. The question is whether they are irregular within the expected range, or outside it.
Urgent features
Timing
This tool uses the adolescent ranges. Past about 18, with periods established, the adult ranges apply instead and the tool will say so rather than give you the wrong answer.
This matters more than her age — the expected pattern is counted from the first period, not from a birthday.
Flow and other symptoms
Result
What this suggests
What produced this
Every line below came from one of the answers. Nothing else was weighted.
Read this alongside the result
The timing of breast development is the weakest input here, because it depends on recall and on a judgment that is hard to make from outside. If the result hinges on it, treat the result as a prompt to have someone examine her rather than as an answer.
Self-assessed breast Tanner staging is concordant with blinded physician examination in under half of girls, with κ around 0.28, and specificity falls further with higher BMI. Only the B1-versus-B2+ binary and approximate interval were used in this output.
Evidence base
Sources
Every threshold in this tool traces to one of these. Vancouver format, numbered in order of first use.
- American College of Obstetricians and Gynecologists' Committee on Adolescent Health Care. Committee Opinion No. 651: Menstruation in girls and adolescents: using the menstrual cycle as a vital sign. Obstet Gynecol. 2015;126(6):e143–e146. doi:10.1097/AOG.0000000000001215 Endorsed by the American Academy of Pediatrics. Supplies every cycle threshold used here: median menarche between 12 and 13 years; 98% have started by 15, within 3 years of thelarche; the threshold moves to 14 with hirsutism, disordered eating or excessive exercise; most bleed 2 to 7 days at the first menses; 90% of early cycles fall between 21 and 45 days; by the third year 60 to 80% are 21 to 34 days; and an interval of 90 days or more is the 95th percentile and uncommon even in adolescence.
- American College of Obstetricians and Gynecologists' Committee on Adolescent Health Care. Committee Opinion No. 785: Screening and management of bleeding disorders in adolescents with heavy menstrual bleeding. Obstet Gynecol. 2019;134(3):e71–e83. doi:10.1097/AOG.0000000000003411 Basis for the coagulopathy pathway: heavy bleeding from menarche onward, easy bruising, frequent nosebleeds, bleeding after dental work or a family history all raise the index of suspicion, and serum ferritin is part of the assessment. Adolescents with severe heavy menstrual bleeding should be screened rather than treated symptomatically alone.
- Rasmussen AR, Wohlfahrt-Veje C, Tefre de Renzy-Martin K, et al. Validity of self-assessment of pubertal maturation. Pediatrics. 2015;135(1):86–93. doi:10.1542/peds.2014-0793 898 children and 1,173 parents assessed against blinded physician staging. Breast stage was assessed correctly by 44.9% of girls, κ = 0.28; pubic hair performed considerably better at 66.8%, κ = 0.55. The reason this tool asks only whether breast development has started rather than asking anyone to grade it, and the reason the output is deliberately conservative. Author list abbreviated; verify full order before formal citation.
- Peng Y, Huang W, Zhang Z, et al. Validity of web-based self-assessment of pubertal development against pediatrician assessments. Pediatr Investig. 2018;2(3):159–165. doi:10.1002/ped4.12050 Independent confirmation of the same pattern: breast self-assessment reached only moderate agreement with pediatrician assessment (weighted κ 0.495) while pubic hair reached 0.878. Also documents that excess adipose tissue degrades breast staging accuracy for self-raters and examiners alike. Author list abbreviated; verify before formal citation.
- Teede HJ, Tay CT, Laven JJE, et al. Recommendations from the 2023 international evidence-based guideline for the assessment and management of polycystic ovary syndrome. J Clin Endocrinol Metab. 2023;108(10):2447–2469. Source of the adolescent caution applied here: in adolescents both hyperandrogenism and ovulatory dysfunction are required, and neither ultrasound nor AMH should be used within 8 years of menarche because normal pubertal physiology overlaps too heavily. This tool therefore flags the pattern for discussion and never suggests the diagnosis.
- Mountjoy M, Ackerman KE, Bailey DM, et al. 2023 International Olympic Committee's (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs). Br J Sports Med. 2023;57(17):1073–1097. doi:10.1136/bjsports-2023-106994 Basis for the energy-availability pathway: delayed menarche and both primary and secondary amenorrhea are recognised indicators of low energy availability, and early intervention limits the skeletal and cardiovascular consequences. Author list abbreviated; verify before formal citation.
- Wang Z, Asokan G, Onnela JP, et al. Menarche and time to cycle regularity among individuals born between 1950 and 2005 in the US. JAMA Netw Open. 2024;7(5):e2412854. doi:10.1001/jamanetworkopen.2024.12854 Context for the falling age at menarche: mean fell from 12.5 to 11.9 years across the birth cohorts studied, early menarche before age 11 rose from 8.6% to 15.5%, and the proportion reaching cycle regularity within two years fell from 76% to 56%. The lengthening time to regularity is why this tool weights gynecologic age rather than chronological age.
- Kaplowitz PB, Oberfield SE; Drug and Therapeutics and Executive Committees of the Lawson Wilkins Pediatric Endocrine Society. Reexamination of the age limit for defining when puberty is precocious in girls in the United States: implications for evaluation and treatment. Pediatrics. 1999;104(4 Pt 1):936–941. The 1999 proposal to lower the evaluation threshold to age 7 in White girls and 6 in Black girls, following the Pediatric Research in Office Settings survey. This tool does not apply those thresholds — see the note in the output on why. Cited so the disagreement is visible rather than hidden.
- Latronico AC, Roberts SA, Alonzo M, et al. Central precocious puberty: an Endocrine Society clinical practice guideline. Presented at: ENDO 2026; June 2026; Chicago, IL. ⚠️ NOT VERIFIED against the published document. Secondary reporting indicates 4 to 6 months of observation for girls under 7 with isolated Tanner B2 development before extensive testing, with immediate evaluation for B3 or above, growth velocity above 6 cm per year, documented progression, or neurological symptoms. This tool does not implement those recommendations, because they have not been verified here. Listed so the reader knows current guidance exists that this tool does not yet reflect.
What this tool deliberately does not do. It does not stage puberty, estimate adult height, predict when periods will start, or name a diagnosis. It sorts into four levels of urgency, shows its reasoning, and stops there.