Estrogen in perimenopause rarely declines in a straight line. Instead of a slow, predictable fall it often swings sharply from month to month. These peaks and troughs are the engine behind many of the symptoms women notice first: mood volatility, shorter cycles, heavier bleeding, and the sudden warmth of a hot flush.
Why the swings happen
Your ovaries are winding down their egg supply, and the brain responds by pushing follicle-stimulating hormone (FSH) higher to coax the ovaries along. Some months your ovaries still produce a strong estrogen surge; other months they barely respond. The result is an erratic hormone profile rather than a steady downward line.
What you can do
Tracking your cycle and symptoms is the most useful thing you can do. Patterns show up over two or three months that are invisible day to day. Bring that record to your clinician. A page of dates beats a vague "I feel off".
Lifestyle foundations matter too: consistent sleep, regular movement and stress regulation all help with the troughs. When symptoms get in the way of daily life, NICE's guideline NG23 and the Pakistan Menopause Society's 2026 recommendations both list HRT as a first-line option to ask about. The picture NICE gives of its risks is not the one-size-fits-all danger the 2002 headlines made of it. Whether it suits you is your doctor's call. Talk to a menopause-aware clinician, not any GP who happens to be free.