What is the definition of perimenopause according to the Stages of Reproductive Aging Workshop (STRAW) classification?

Definition of Perimenopause According to STRAW Classification

According to the Stages of Reproductive Aging Workshop (STRAW) classification, perimenopause is defined as the stage when menstrual irregularities occur, with cycles extending by 7 or more days, corresponding to option C.

STRAW Classification of Perimenopause

The STRAW classification provides a standardized framework for understanding reproductive aging in women. According to the evidence:

• Perimenopause (also called menopausal transition) is characterized by menstrual cycle irregularities, specifically cycles that vary from the normal range of 21-35 days 1
• It represents a reproductive transition period with declining fertility that occurs before the final menstrual period 2
• The perimenopause has two distinct stages:
  1. Early menopausal transition: Characterized by mostly regular menstrual cycles with relatively few interruptions
  2. Late menopausal transition: Characterized by more prolonged amenorrhea lasting at least 60 days 3

Key Diagnostic Features of Perimenopause

• The primary defining characteristic is the change in menstrual cycle length (extending by 7 or more days)
• This stage is marked by wide hormonal fluctuations rather than simply declining estrogen levels 4
• Contrary to common belief, perimenopause is not defined by:
  • The onset of hot flashes (although these may occur)
  • Heavier periods (although menorrhagia may affect 25% of perimenopausal women) 5
  • A specific age (although it typically begins in a woman's mid-30s to 40s)

Hormonal Changes During Perimenopause

Perimenopause involves complex hormonal changes:

• Erratically higher estradiol levels (averaging 26% higher than in regular reproductive years)
• Decreased progesterone levels due to insufficient ovulation or anovulatory cycles
• Disturbed ovarian-pituitary-hypothalamic feedback relationships 4
• Approximately one-third of perimenopausal cycles have a major surge in estradiol during the luteal phase (LOOP event) 4

Clinical Implications

• Women in perimenopause can still ovulate and become pregnant, requiring continued contraception until menopause is confirmed 2
• Perimenopause is associated with increased risk for various symptoms including vasomotor symptoms (80%), menorrhagia (25%), and mastalgia (10%) 5
• This stage represents a systemic inflammatory phase that may increase risk for later neurodegenerative diseases 3

Important Distinctions

• Perimenopause is not the same as menopause, which is defined as 12 consecutive months without menstruation 6
• FSH and Inhibin B levels are not effective for predicting proximity to menopause 4
• The median age of natural menopause (not perimenopause) is 51 years in the United States 6

Understanding the STRAW classification helps clinicians accurately identify women in perimenopause and provide appropriate counseling regarding symptoms, fertility, and treatment options.