Abstract

Research Article

Fiesta vs. Stress Condition the Incidence and the Age at Menarche. Forty Years of Research

Carlos Y Valenzuela*

Published: 05 August, 2025 | Volume 8 - Issue 3 | Pages: 069-073

Introduction: The annual rhythm of menarche was proposed to be due to climatic annual variations. The discovery that peaks of incidence of menarche were found in the same months in the North and the South Hemispheres made us to think this hypothesis was not correct. Then we proposed that periods of study (stress) and vacation (relaxation, fiesta) were better factors for this rhythm. If this is so, days of fiesta should present more menarches than current days. In the second hypothesis the age at menarche should be modified by the vacation-study rhythm. Thus, I tested two hypotheses: I) This rhythm and the age at menarche are conditioned by climate factors mostly seasonal variations. II) the contrast between expectancy of fiesta (relaxation) and stress is the main factor of the rhythm and the variation on the age at menarche during the year.
Method: The monthly incidence and age at menarche were obtained from samples of girls in Santiago (Chile), Medellín (Colombia), Debrecen (Hungary), Chennai (India) with data collected directly in these countries. A sample from Barrinhas (Riberao Preto, Brazil) was taken from literature. The climatic hypothesis was tested knowing the main climatic parameters by the latitude of these cities. The annual study-vacation rhythm was obtained from the academic calendar at any city and from direct information of our colleagues working in these cities. A correlate between the climatic rhythm and the study-vacation rhythm with the incidence or age at menarche complete the refutation or affirmation of the hypotheses. Also, the expected peaks of menarche at significance fiesta-days or the birthday were studied directly form the calendar of holidays or the cultural information given by our colleagues. 
Results: In the five samples taken individually or together there were clear contradictions with the climatic hypothesis. On the contrary the fiesta-stress hypothesis shows a clear correlation with the monthly incidence and the age at menarche. Days of national, religious fiesta or the birthday showed greatly significant peaks of menarche. 
Conclusion: Data refute the climatic hypothesis of the annual rhythm of menarche and agree with the fiesta (vacation)-stress (study) hypothesis.

Read Full Article HTML DOI: 10.29328/journal.cjog.1001190 Cite this Article Read Full Article PDF

Keywords:

Menarche; Annual rhythm; Seasonal factors; Fiesta-stress expectancy

References

  1. Bojlen K, Bentzon WW. Seasonal variation in the occurrence of menarche. Dan Med Bull. 1974;21:161–8. PMID: 4605089. Available from: https://pubmed.ncbi.nlm.nih.gov/4605089/
  2. Gueresi P. Monthly distribution of menarche in three Provinces of North Italy. Ann Hum Biol. 1997;24:157–68. Available from: https://doi.org/10.1080/03014469700004892
  3. Matchock RL, Susman EJ, Brown FM. Seasonal rhythms of menarche in the United States: correlates to menarcheal age, birth age, and birth month. WHI. 2004;14(6):184–92. Available from: http://dx.doi.org/10.1016/j.whi.2004.07.007
  4. Patri A, Valenzuela CY, Morales I, Saavedra I, Figueroa L. Age at menarche of girls from public schools of the Northern Area of Santiago. Cuad Med Soc (Santiago, Chile). 1980;21:12–20.
  5. Valenzuela CY, Nuñez E, Tapia C. Month at menarche: a re-evaluation of the seasonal hypothesis. Ann Hum Biol. 1991;18:383–93. Available from: https://doi.org/10.1080/03014469100001682
  6. Valenzuela CY, Srikumari CR, Gopinath PM, Ghose N, Gajalakshmi P, Csoknyay J. New evidence of non-seasonal factors in the menarche rhythm. Biol Res. 1996;29:245–51. Available from: https://pubmed.ncbi.nlm.nih.gov/9278715/
  7. Valenzuela CY. The monthly rhythm of incidence and age at menarche: Thirty-five years of research. The circa-vacation-study expectancy rhythm of incidence and age at menarche. Biol Res. 2013;46:21–6. Available from: http://dx.doi.org/10.4067/S0716-97602013000100003
  8. Valenzuela CY. Scientific Epistemology. Saarbrücken, Alemania: Editorial Académica Española; 2016. Available from: https://sochigen.cl/valenzuela-carlos-2016-epistemologia-cientifica-editorial-academica-espanola/
  9. Valenzuela CY, Pineda N, Olarte G, Vásquez G. Annual rhythm of menarche in Medellín, Colombia. Rev Med Chile. 1996;124:437–41. Available from: https://www.bibliotecadigital.uchile.cl/discovery/fulldisplay?vid=56UDC_INST:56UDC_INST&docid=alma991001246869703936&context=L
  10. Valenzuela CY, Srikumari CR, Csoknyay J, Pineda N. Annual school rhythms (study holidays) and menarche. Rev Med Chile. 1999;127:143–50. Available from: https://pubmed.ncbi.nlm.nih.gov/10436693/
  11. Valenzuela CY. Menarche day, party expectation and memory bias. Rev Med Chile. 2004;132:299–306. Available from: http://dx.doi.org/10.4067/S0034-98872004000300004
  12. Valenzuela CY. Confirmation of the vacation-study expectation as a main factor in the annual incidence rate and age of menarche. Rev Med Chile. 2006;134:606–12. Available from: http://dx.doi.org/10.4067/S0034-98872006000500009

Figures:

Similar Articles

Recently Viewed

Read More

Most Viewed

Read More

Help ?