How does perimenopause affect menstruation?

As women enter perimenopause, the first symptom they usually notice is a change in their menstrual cycle. Periods become irregular and hard to predict. They may be short or last longer than usual. The time between periods may also get longer or shorter. The menstrual flow may be lighter or heavier than usual. Over a period of several years, menstrual periods gradually get lighter and further and further apart until they stop altogether. After 12 months without a period, you are in menopause.

Dr. Julia Schlam Edelman
OBGYN (Obstetrician & Gynecologist)

Irregular menstrual periods are the most frequent sign of perimenopause. Ninety percent of women experience changes in their menstrual cycle for 4 to 10 years preceding postmenopause. Menstrual cycles in perimenopause often disappear, only to reappear without warning. I have heard horror stories about the sudden, unexpected return of a menstrual period that can involve bleeding through clothes in a public setting. If this happens to you, rest assured: you are not alone!

During perimenopause, your menstrual flow may become lighter or heavier. You may bleed for longer or shorter periods of time. You may miss periods or bleed more often.

Not all changes in menstrual periods are due to perimenopause alone. Sometimes there is a medical cause for the change in menstrual periods, whether the periods become heavier and longer, or lighter and less frequent. Thyroid disease is one common cause of these changes. Growths in the uterus such as polyps or fibroids may alter bleeding patterns. Finally, pre-cancer (endometrial hyperplasia) or cancer can also cause heavy or prolonged bleeding even after skipping several menstrual periods. Discuss changes in your menstrual cycle with your clinician to identify the cause.

Perimenopause is the time when menstrual cycles become more irregular due to changing hormones. Because our hormones are not following a consist pattern as they have in the past, those changes in our periods can range from shorter, more frequent cycles to longer, more spaced out cycles. They can include heavier, more painful periods or skipping periods for a month or two, all depending on what our hormones levels are at a time.
Perimenopausal symptoms are explained by the waxing and waning of ovarian function. This is all normal, but understanding what may not be normal is just as important. Periods every 21-35 days during perimenopause are normal, while bleeding at intervals less than 21 days or bleeding more than eight days at a time is not normal. If you experience this kind of bleeding, you should see your gynecologist.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.