Periodogram analysis of menstrual cycles

Abstract

Periodogram analysis of long‐term menstrual calendars of women shows that there is an individual dominant frequency of the onsets of menstrual bleeding. In the cases under study, corresponding dominant periods range from 24.2 to 30.2 days. The individual dominant period slightly varies with age, probably rhythmically. Ten menstrual calendars were analyzed. Total number of recorded episodes was 1,235. Results were compared with the periodograms of two simulated cases: one case represented a perfectly regular girl and the other represented a girl whose cycle length varied randomly between 21 and 40 days. Periodogram analysis appears to be more appropriate tool for study of menstrual cycles than conventional statistical measures such as mean, mode, variation and standard deviation.

Abstracting keywords:

• Circamensial rhythm
• menstrual cycle
• time series analysis

Notes

Dept of Physics, The American University, Washington, D. C. 20016, U.S.A.