Set Text Size: S   M   L

Article |


by Dr. Jerilynn C. Prior, Scientific Director, Centre for Menstrual Cycle and Ovulation Research

What's Normal?

During perimenopause women are often most engaged in work or vocation or may be just getting back to full time work after childcare years. Many changes in relationships, home life and the needs of parents characterize women’s mid-life.

Perimenopause lasts from six to 10 years for most women. This stage begins gradually during regular cycles and ends when a year has passed since the final menstrual period. The onset of perimenopause is different for different women but is characterized by cycles that become closer together. Approximately 25% will begin to have night sweats. An unknown percentage of women with regular cycles will have increased breast tenderness and enlargement. About 20-30% will have abnormally heavy flow for one or more cycles. Most women experience some middle of the night sleep disturbances, mood swings and less ability to predict flow. Some women will experience nausea, new or recurrent and severe migraine headaches, weight gain and palpitations.

Later stages of perimenopause begin with irregular cycles that may involve alternating short and long cycles. During this portion of perimenopause more women will have night sweats and some will start having daytime hot flushes. Sleep disturbances may increase and rapid bone loss begins with the onset of irregular cycles. The final year of perimenopause is from the final menstrual period for one year. By then breast tenderness is improving, and hot flushes for some, but sleep disturbances and night sweats/hot flushes are at their maximal.

What Can Go Wrong?

Women early in perimenopause may present with severe fatigue, sleep disturbances and other symptoms and commonly are diagnosed as having fibromyalgia or chronic fatigue syndrome. Women with persistent heavy bleeding during early perimenopause include those with ineffectively treated anovulatory androgen excess since adolescence, who are overweight and who have had chronic anovulation without androgen excess. Women with anovulatory androgen excess or who have been inactive or overweight for many years may develop insulin resistance or frank Type 2 Diabetes Mellitus.

Severe nausea may cause investigations for liver problems, severe migraine headaches cause evaluation for the possibility of a brain cancer and palpitations, hyperventilation and chest pressure investigations for heart disease. Increased abdominal cramps and varying bowel movements may lead to the diagnosis of spastic bowel disease. Sometimes women who wake fatigued or who have insomnia are investigated for sleep apnea or restless leg syndrome but more often are diagnosed with and treated for depression. Often anxiety or panic diseases are diagnosed in perimenopause.

Breast cancer is most prevalent in perimenopause, often beginning when women still have regular periods.


The myth of perimenopause is that it is a time of dropping estrogen levels and estrogen deficiency. This idea arose because a separate phase of perimenopause as distinct from menopause was not described until recently and because hot flushes commonly begin in perimenopause. In reality perimenopause estrogen levels average about 20-30% higher than premenopausal values and often swing widely.

Resources and Tools


We Rely On Your Support

If you find these materials helpful, and if you are able, please consider making a donation to cover our costs and support the research and education objectives of the Centre for Menstrual Cycle and Ovulation Research. 

Donate now »