Hostname: page-component-8448b6f56d-mp689 Total loading time: 0 Render date: 2024-04-25T06:26:59.076Z Has data issue: false hasContentIssue false

Cycle day of ovulation

Published online by Cambridge University Press:  31 July 2008

William H. James
Affiliation:
Gallon Laboratory, University College, London

Extract

The length of the post-ovulatory phase in a composite sample of menstrual cycles increases linearly with cycle length until cycle length reaches about 30 days, but thereafter it ceases to increase (Vollman, 1953; Bailey & Marshall, 1970). By contrast, plotted against the mean cycle length of the individual, the length of the post-ovulatory phase continues to increase roughly linearly with mean cycle length. It is concluded (a) that many long cycles are aberrant occurrences among cycles of normal length and are due to lengthening of the pre-ovulatory phase and (b) that where the mean cycle length is long, ovulation, as in shorter cycles, occurs just before the middle of the cycle, so that the post-ovulatory phase is longer than usual.

The most fertile day seems to be the one before mid-cycle. These conclusions are the basis for the following formula for calendar rhythm:

If x is the shortest and y the longest cycle in a woman's menstrual record, the ‘unsafe’ days start on Day (½x − 5) and last for (yx + 8) days.

Type
Research Article
Copyright
Copyright © 1972, Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bailey, J. & Marshall, J. (1970) The relationship of the post-ovulatory phase of the menstrual cycle to the total cycle length. J. biosoc. Sci. 2, 123.CrossRefGoogle Scholar
Barrett, J.C. & Marshall, J. (1969) The risk of conception on different days of the menstrual cycle. Popul. Stud. 23, 455.CrossRefGoogle ScholarPubMed
Cary, W.H. (1948) Results of artificial insemination with an extra-marital specimen (semiadoption). Am. J. Obstet. Gynec. 56, 727.Google Scholar
Farris, E.J. (1956) The period of human ovulation and a consideration of the fertile and infertile periods. Acta endocr. Suppl. 28, 114.Google Scholar
James, W.H. (1963) The arithmetic of the rhythm method of contraception. J. Obstet. Gynaec. Br. Commonw. 70, 470.CrossRefGoogle ScholarPubMed
James, W.H. (1965) Parameters of the menstrual cycle and the efficiency of rhythm methods of contraception. Popul. Stud. 19, 45.CrossRefGoogle Scholar
James, W.H. (1968) A note of correction with reference to parameters of the menstrual cycle and the efficiency of rhythm methods of contraception. Popul. Stud. 22, 409.CrossRefGoogle ScholarPubMed
Matsumoto, S., Nogami, Y. & Ohkuri, S. (1962) Statistical studies on menstruation: a criticism on the definition of normal menstruation. Gunma J. med. Sci. 11, 294.Google Scholar
Murray, D.S. (1959) Statistical method for determination of ovulation time in women. J. Am. med. Ass. 170, 42.Google Scholar
Pommerenke, W.T. (1953) Phenomena correlated with ovulation as guides to the appraisal of the so-called safe period. J. Obstet. Gynaec. Br. Emp. 60, 519.CrossRefGoogle Scholar
Potter, R.G. (1957) Farris's formula for predicting fertile days. Symp. quant. Biol. 22, 175.CrossRefGoogle Scholar
Potter, R.G., Burch, T.K. & Matsumoto, S. (1967) Long cycles, late ovulation and calendar rhythm. Int. J. Fert. 12, 127.Google Scholar
Raboch, J. & Mellan, J. (1966) Cycle day of conception by single therapeutic donor insemination. Int. J. Fert. 11, 281.Google Scholar
Sevag, M.G. & Colton, S.W. (1959) Simple chemical method for the determination of ovulation time in women. J. Am. med. Ass. 170, 13.Google Scholar
Torrano, E.F. & Murphy, D.P. (1962) Cycle day of conception by insemination or isolated coitus. Fert. Steril. 13, 492.CrossRefGoogle ScholarPubMed
Vollman, R. (1953) Über Fertilität und Sterilität der Frau innerhalb des Menstruationcyclus. Arch. Gynäk. 182, 602.Google Scholar
World Health Organisation Scientific Group (1967) Biology of fertility control by periodic abstinence. Tech. Rep. Ser. Wld Hlth Org. No. 360.Google Scholar
Yoshida, Y. (1960) Studies on single insemination with donor's semen. J. Jap. obstet. gynaec. Soc. 7, 19.Google Scholar