What Happens During Perimenopause
Perimenopause is characterized by fluctuating ovarian hormone production beginning years before complete cessation of menses, leading to irregular menstrual cycles, vasomotor symptoms, sleep disturbances, mood changes, and accelerated bone loss. 1, 2
Hormonal Changes
Ovarian production of estrogen and progesterone begins to decrease years before the complete cessation of menses, with hormone levels fluctuating greatly rather than declining in a linear fashion. 1, 2 This fluctuation is the hallmark of perimenopause and explains why symptoms can be unpredictable and variable in intensity. 3
- Estrogen levels fluctuate dramatically during perimenopause, with periods of both high and low levels, contributing to menstrual irregularity. 1, 3
- Testosterone production also declines, though it can convert to estrogen through the aromatase enzyme in peripheral adipose tissue. 4
Physical and Metabolic Consequences
Bone Health
Lower circulating estrogen levels contribute to accelerated bone loss, with bone density decreasing by approximately 2% per year during the first 5 years after menopause, followed by 1% annual loss thereafter. 1
Cardiovascular and Metabolic Changes
- Increased low-density lipoprotein (LDL) levels occur around menopause due to declining estrogen's protective effects. 1
- Increased prevalence of obesity and metabolic syndrome develops during this transition. 5
Common Symptoms and Their Timeline
Vasomotor Symptoms
Hot flashes are experienced by most women and are moderately to severely problematic for approximately one-third. 3 The duration varies significantly:
- Women experiencing hot flashes in early perimenopause have a median duration of 11.8 years. 6
- Women whose symptoms begin only after menopause experience a median duration of 3.4 years. 6
Sleep Disturbances
Sleep problems become more common during perimenopause, affecting 80-90% of women through multiple mechanisms. 7
- Vasomotor symptoms directly disrupt sleep architecture. 7
- Fluctuations in estrogen and progesterone independently affect sleep quality. 7
- Decreased melatonin production and circadian rhythm changes compound the problem. 7
Mood and Cognitive Changes
Depressed mood and increased anxiety show an abrupt rise in prevalence as women approach later stages of the menopausal transition with longer bouts of amenorrhea. 3
- Women report "not feeling like myself anymore" with symptoms including brain fog, panic attacks, mood swings, and palpitations. 6
- These symptoms can occur even years before menopause and in the presence of still adequate estrogen levels. 6
- In one online study, 20% of women reported unexplained symptoms during the menopausal transition. 6
Genitourinary Symptoms
Vaginal dryness and dyspareunia affect approximately one-third of women as they enter the latter stages of transition. 3
- Unlike hot flashes and mood issues, vaginal symptoms will not resolve without treatment. 3
- These symptoms comprise genitourinary syndrome of menopause (GSM), which can strongly affect quality of life. 6
Additional Symptoms
Perimenopause may present with a wide constellation of symptoms including:
- Mastalgia, joint pain, vertigo, and headache. 6
- Sleep disturbances, including insomnia and sleep-related breathing disorders. 7
- Movement disorders during sleep. 7
Clinical Pitfalls
Nearly 90% of women seek healthcare provider advice for menopausal symptoms, yet many symptoms go unrecognized as perimenopausal in origin. 3, 6
- Extensive medical work-ups may be pursued if perimenopause is not considered as the cause of vague symptoms like palpitations, panic attacks, or brain fog. 6
- Symptoms often interact with one another: depressed women tend to experience worse hot flashes and worse sleep. 3
Long-Term Health Implications
Women will live up to one-third of their lives being either peri- or postmenopausal, making understanding this transition essential. 2
The lifetime risk for chronic diseases in postmenopausal women includes: