Many of us have come to expect irregular cycles or hot flashes as the tell-tale signs that perimenopause has begun. But the transition can be harder to recognize when your periods are still regular and the changes show up elsewhere first. In a 2026 international survey of more than 17,000 women, hot flashes were the most widely recognized symptom. However, among respondents aged 35 and older, 83% reported fatigue and physical or mental exhaustion, alongside irritability, mood changes, sleep problems, digestive issues and anxiety. These symptoms can have many possible causes, but the findings help show why the changes women experience during midlife may not always match the symptoms they associate with perimenopause.
What Is Perimenopause, and When Does It Start?
Perimenopause is the transition leading up to menopause, when ovarian function and reproductive hormone patterns become increasingly variable. It usually begins during a woman's 40s, although timing varies. Menopause is confirmed after 12 consecutive months without a period, assuming another medical explanation is absent.
The 2024 CMAJ review, Perimenopause, explains that reproductive staging relies on persistent changes in menstrual cycle length. However, symptoms associated with hormonal changes may appear before these formal criteria are met. The European Society of Endocrinology guidelines also emphasize considering symptoms within a woman's broader clinical picture.
Can You Be in Perimenopause if Your Periods Are Still Regular?
Symptoms associated with the menopause transition can occur while periods remain regular, although formal reproductive staging makes an important distinction.
Healthcare professionals use STRAW+10, the Stages of Reproductive Aging Workshop framework, to describe reproductive aging. It identifies entry into the early menopause transition through persistent changes in menstrual cycle length. Women with regular cycles may remain in the late reproductive stage in this framework, even though symptoms associated with hormonal changes are present.
The 2025 Australian Women's Midlife Years study found that women with regular cycle timing, changed menstrual flow and vasomotor symptoms, such as hot flashes or night sweats, reported a greater burden of bothersome symptoms than women without vasomotor symptoms. However, a 2026 follow-up found that changes in menstrual flow without vasomotor symptoms were not a reliable indicator of entering the menopause transition.
Together, these findings suggest that symptoms deserve consideration alongside menstrual history, even when formal staging criteria have not been met.
What Are the First Signs of Perimenopause?
The first signs of perimenopause vary between women. There is no single established first sign of perimenopause or a fixed order in which symptoms appear. Some women notice changes in sleep, mood or energy, while others experience vasomotor or menstrual changes first. As the international Flo survey illustrates, the range of reported symptoms is broad. Since many have other possible causes, their timing, severity, and impact on daily life are important considerations.
Fatigue and Exhaustion
Fatigue may appear as reduced stamina, mental exhaustion or difficulty managing familiar activities. A 2026 study of psychological symptoms during perimenopause found that women who self-identified as perimenopausal reported greater exhaustion than premenopausal participants, even after adjustment for several other factors.
Since thyroid conditions, anemia, poor sleep and mental-health concerns can produce similar symptoms, a broader assessment is needed.
Sleep Changes
Sleep difficulties during midlife may involve waking frequently, struggling to return to sleep or feeling less rested in the morning. Sleep problems are common during the menopause transition and may occur with or without night sweats.
Stress, anxiety, sleep apnea and other medical conditions may also contribute, making an individualized assessment valuable.
Mood and Mental Health Changes
Changes in mood may include increased irritability, anxiety, emotional sensitivity or feeling less able to manage everyday stress.
In a 2024 systematic review and meta-analysis researchers found higher odds of depressive symptoms among perimenopausal women compared with premenopausal women. Similarly, the previously mentioned study of psychological symptoms of perimenopause found greater depressive mood, anxiety and irritability among women identifying as perimenopausal.
These associations suggest that a woman’s reproductive stage may be one factor worth considering when emotional changes arise during midlife. However, personal circumstances, previous mental-health concerns and other medical factors also need to be considered as part of the assessment.
Brain Fog and Cognitive Changes
Forgetting familiar words, losing your train of thought or finding multitasking more difficult can feel frustrating. A 2025 review of cognitive, sleep and mood changes during the menopause transition describes how these experiences can overlap with fatigue, sleep disturbances and emotional symptoms. Considering these factors together may help identify ways to support cognitive well-being.
Changes in Headaches and Migraines
Migraine patterns can change during perimenopause as reproductive hormone levels become more variable. Research suggests that some women experience changes in migraine frequency, severity or predictability, particularly those with a history of menstrual migraine. A 2026 review of migraine across the menopause transition describes how fluctuating estradiol and progesterone may influence migraine patterns during perimenopause.
Because headaches and migraines can also change for many other reasons, new or worsening symptoms should be assessed in the context of the woman’s overall health and migraine history.
Hot Flashes and Night Sweats
Hot flashes cause sudden warmth, sometimes accompanied by flushing or sweating, while night sweats can disrupt sleep. One survey of Australian women found that bothersome hot flashes increased substantially between premenopause and late perimenopause.
In this study, hot flashes showed a clearer association with reproductive stage than symptoms such as low mood or poor memory, although individual experiences vary.
Vaginal, Urinary and Sexual Changes
Vaginal dryness, irritation, discomfort during sex and urinary symptoms may emerge as estrogen exposure declines. The 2025 International Menopause Society recommendations recognize these concerns as important aspects of midlife healthcare. Sexual desire may also change, influenced by sleep, mood, relationships, medications and overall health. Discussing these experiences can help identify appropriate care.
Menstrual Changes
Changes in menstrual flow, cycle length, skipped periods or longer intervals between periods may develop during the menopause transition. Persistent changes in cycle length are central to formal reproductive staging. Researchers are also exploring whether changes in flow, particularly alongside hot flashes, provide additional information about earlier hormonal changes. Tracking menstrual patterns alongside other symptoms can help inform a clinical assessment.
Why Is Perimenopause Sometimes Missed?
Perimenopause can be difficult to recognize because fatigue, anxiety, sleep difficulties and concentration problems have several possible causes. In a 2026 survey of 7,640 American women, 34% of respondents aged 35 and older were unsure of their reproductive stage, rising to 42% among those aged 40 to 44. Among respondents explaining their uncertainty, 56% reported difficulty interpreting symptoms or distinguishing them from other causes.
A 2024 observational study also identified overlap between the age range associated with the menopause transition, mental-health diagnoses and psychiatric medication prescribing. Menopause stage was not consistently documented, so the study cannot determine whether the symptoms were menopause-related.
The findings reinforce the value of considering hormone health alongside other medical and mental-health factors when new symptoms arise during midlife.
How Do I Know if I'm in Perimenopause?
Recognizing perimenopause involves reviewing your symptoms, menstrual history and overall health rather than relying on a single test.
A healthcare provider may consider:
Menstrual timing, flow and recent changes
Hot flashes, night sweats
Sleep quality
Mood, anxiety, fatigue and concentration
Vaginal, urinary and sexual symptoms
Medical history, medications and other possible causes
FSH and estradiol levels fluctuate during the menopause transition, limiting the usefulness of a single hormone test. The European Society of Endocrinology guidelines generally recommend clinical assessment for women over 45 with typical symptoms.
Testing may be helpful when menopause is suspected unusually early, symptoms are atypical or another condition requires investigation. Thyroid disease, iron deficiency, pregnancy, sleep disorders and mental-health concerns may also be considered.
Can HRT Help During Perimenopause?
Hormone replacement therapy (HRT) can be considered during perimenopause when clinically appropriate. A woman does not have to wait until she has reached menopause to discuss treatment.
The European Society of Endocrinology clinical practice guidelines support an individualized approach that considers symptoms, medical history, personal risks and treatment preferences.
The International Menopause Society recognizes menopausal hormone therapy as the most effective treatment for bothersome hot flashes and night sweats. Systemic therapy also reduces bone loss during treatment.
Treatment decisions consider symptoms, medical history, bleeding patterns, contraception needs and individual risks. Women with a uterus generally require progestogen alongside systemic estrogen to protect the uterine lining. Care may include hormone therapy, non-hormonal treatments or a combination of approaches.
When Should I Talk to Someone About Perimenopause?
Changes affecting your sleep, mood, energy, or daily life are good reasons to seek guidance, even while your periods remain regular.
Emotional exhaustion, frustration, and feeling overwhelmed can be particularly difficult. Heavy bleeding, bleeding between periods, bleeding after sex and bleeding after menopause also warrant medical evaluation.
At Rosie Health, we assess your symptoms in the context of your overall health and help you understand which treatment options may be appropriate for you. Book a consultation today to learn more.
This article provides general educational information and does not replace individualized medical advice. Speak with a qualified healthcare provider about your specific circumstances.
Frequently Asked Questions:
How long does perimenopause last?
Perimenopause commonly lasts several years, although duration varies. Symptoms and menstrual patterns may change throughout the transition.
Can perimenopause symptoms come and go?
Yes. Sleep difficulties, mood changes, hot flashes and fatigue may fluctuate in frequency and intensity over time.
Can I still get pregnant during perimenopause?
Yes. Ovulation may continue, making pregnancy possible. Discuss contraception with your healthcare provider, since menopausal hormone therapy does not prevent pregnancy.
Does everyone need treatment for perimenopause?
No. Treatment depends on symptoms, their effect on quality of life, medical history and personal preferences. Some women need minimal support, while others benefit from clinical treatment.
Sources:
Alsugeir et al. Common mental health diagnoses arising from or coinciding with menopausal transition and prescribing of SSRIs/SNRIs medications and other psychotropic medications, Journal of Affective Disorders (2024),
https://pubmed.ncbi.nlm.nih.gov/39142573/
Aras et al. Clustering of >145,000 symptom logs reveals distinct pre, peri, and menopausal phenotypes (2025),
https://pubmed.ncbi.nlm.nih.gov/39753725/
Islam, Bond, Ghalebeigi et al. Prevalence and severity of symptoms across the menopause transition: Cross-sectional findings from the Australian Women's Midlife Years (AMY) Study (2025),
https://pubmed.ncbi.nlm.nih.gov/40720963/
Badawy et al. The risk of depression in the menopausal stages: A systematic review and meta-analysis, Journal of Affective Disorders (2024),
https://pubmed.ncbi.nlm.nih.gov/38642901/
Balasubramanian et al. Prevalence and incidence of depressive, anxiety, and insomnia symptoms in perimenopausal and postmenopausal women: Systematic review and meta-analysis (2026),
https://pubmed.ncbi.nlm.nih.gov/41946603/
Dreisler et al. Perimenopausal abnormal uterine bleeding, Maturitas (2024),
https://pubmed.ncbi.nlm.nih.gov/38412750/
European Society of Endocrinology. Clinical practice guideline for evaluation and management of menopause and the perimenopause, European Journal of Endocrinology (2025),
https://pubmed.ncbi.nlm.nih.gov/41082911/
Global Perspectives on Perimenopause: A Digital Survey of Knowledge and Symptoms Using the Flo Application (2026),
https://pubmed.ncbi.nlm.nih.gov/41603602/
International Menopause Society. Recommendations and key messages on women’s midlife health and menopause, Climacteric (2025),
https://pubmed.ncbi.nlm.nih.gov/41433054/
Korn & Bernstein. Migraine across the menopausal transition and beyond: A narrative review, Headache (2026),
https://pubmed.ncbi.nlm.nih.gov/41934093/
Lega & Jacobson. Perimenopause, CMAJ (2024),
https://pmc.ncbi.nlm.nih.gov/articles/PMC11482657/
Maki, Panay & Simon. Sleep disturbance associated with the menopause, Menopause (2024),
https://pubmed.ncbi.nlm.nih.gov/38916279/
Psychological Symptoms During Perimenopause: A Global Perspective (2026),
https://pubmed.ncbi.nlm.nih.gov/42517353/
Symptom profiles in the late reproductive stage, earlier premenopause and early perimenopause in the absence of vasomotor symptoms (2026),
https://pubmed.ncbi.nlm.nih.gov/41813093/
Williams & Maki. A Review of Cognitive, Sleep, and Mood Changes in the Menopausal Transition: Beyond Vasomotor Symptoms, Obstetrics & Gynecology (2025),
https://pubmed.ncbi.nlm.nih.gov/40403308/