In the medical literature these two terms, pre-menopause and peri-menopause are now called the ‘menopausal transition’. The two criteria for measuring the beginning of the menopausal transition are:
- The onset of irregular cycle lengths
- The change in hormone levels, specifically of FSH
One definition states the menopausal transition begins with variations in menstrual cycle length in a woman who has levels of FSH in the early follicular phase that are increased above levels found in regularly menstruating women under the age of 35, and ends with the final menstrual period1. The median age of onset of transition in one study was quoted as 45.5 years, with a median duration of 4.8 years.7
STRAW REPORT -The definition of the menopausal transition
In order to reach agreement as to when the menopause transition begins, a consensus document was issued in 2001 by the STRAW Report5 (Stages of Reproductive Aging Workshop), which proposed that reproductive life could be characterized by seven stages. Before menopause the reproductive life could be divided into the reproductive years (three stages) and the transition years (two stages: early and late transition). Postmenopause (two stages) follows the final menstrual period, (FMP).
STRAW uses two criteria to assess menopausal transition- cycle length and FSH level. STRAW proposes an elevated FSH level obtained in the early follicular phase that exceeds 2SDs of the mean level for a sample of normal women of peak reproductive age (25-30 years).5 According to STRAW in the early menopausal transition (stage -2), a woman’s menstrual cycles remain regular but the duration changes by 7 days or more (e.g. her regular cycles are now every 24 instead of 31 days).5 According to STRAW the late menopausal transition (stage -1) is characterized by two or more skipped menstrual periods and at least one intermenstrual interval of 60 days or more.5
An article by Harlow et al7 which reviewed the work of STRAW and others suggests that the onset of early menopausal transition may be best described by ovarian activity consistent with the persistent >6 day difference, i.e. the length of the cycle is >6 day different from the previous cycle and this magnitude of difference is observed again within ten cycles.7
- Liu JH, Gass ML; ‘Management of the perimenopause’; 2006; Pub. McGraw-Hill, ISBN 0-0-142281-1
- Odeblad Erik; ‘The discovery of different types of cervical mucus and the Billings Ovulation Method’; Bulletin of the Ovulation Method Research and Reference Centre of Australia, Vol 21, No3; 3-35; Sept 1994. (on the internet if you google ‘Erik Odeblad, cervical mucus’).
- Odeblad E, ‘Investigations on the physiological basis for fertility awareness’ page 7; Bulletin for the Ovulation Method Research and ReferenceCentre of Australia, vol 29, no 1, p2-11, march 2002, (internet, Billings Ovulation Method)
- Flynn A, Brooks M; ‘The Manual of Natural Family Planning’; pages 74-80; 1996; ISBN 0 7225 3115 X
- Soules MR, Sherman S, Parrot E et al; Executive summary: Stages of Reproductive Aging Workshop (STRAW). Fertil Steril. 2001; 76: 874
- Flynn A, Worthington W; ‘Teachers Training Manual’; ‘symptothermal multiple index method’ of natural family planning.
- Harlow S D, Mitchell ES, Crawford S; ‘The ReStage Collaboration: defining optimal bleeding criteriafor onset of early menopausal transition’; Fertil Steril; vol 89, No1, Jan 2008.
- Alvero Ruben, Schlaff William D; ‘Reproductive endocrinology and infertility, The Requisites in Obstetrics and Gynecology’; 2007, page 229; ISBN-13:978-0-323-04054-9
- McKinlay SM; ‘The normal menopause tradition: and overview ‘; Maturitas; 1996; 23:137
- Wallace RB, Sherman BM et al; ‘Probability of menopause with increasing duration of amenorrhea in middle-aged women’; Am. J. Obstet. Gynecol. 135: 1021, 1979.
- Richardson SJ, Senikas V, Nelson JF; ‘Follicular depletion during the menopausal transition: evidence for accelerated loss and ultimate exhaustion’; J Clin Endocrinol Metab. 1987; 65:1231
- Brown JB; ‘Types of ovarian activity in women and their significance: the continuum (a reinterpretation of early findings)'; Human Reproduction Update; Vol 17; No 2; p141-158. (this is a classic article which gives a greater understanding of the menstrual cycle throughout the reproductive life).
- Cynthia A. Stuenkel, MD, Margery Gass MD et al; ‘A decade after the Women’s Health Initiative – the experts agree'; Fertility and Sterility; vol 98, no 2; August 2012; p313-314.