The question
You have always been someone who managed anxiety reasonably well. Or perhaps you have dealt with it before, but it settled. Now, in your 40s, it is back and feels different: more physical, more pervasive, more difficult to reason with. You are wondering what has changed.
The answer, for many women in this situation, is hormonal. The perimenopause transition begins, on average, in the mid to late 40s, and one of its most common, least discussed, and most frequently misattributed effects is anxiety.
The short answer
Feeling more anxious in your 40s is very often a sign of perimenopause, not just life circumstances or personal fragility. Oestrogen and progesterone both play significant roles in regulating the brain’s emotional and stress systems, and when they fluctuate during the perimenopause transition, anxiety is a frequent and predictable consequence.
Why hormones and anxiety are so closely connected
Oestrogen influences serotonin, the neurotransmitter most associated with mood stability. It also modulates the amygdala, the brain’s threat-detection centre. When oestrogen fluctuates during perimenopause, the brain’s anxiety threshold lowers: situations that were previously manageable now trigger a more intense response.
Progesterone, which declines early in perimenopause, supports GABA, the brain’s primary calming neurotransmitter. With less progesterone, the nervous system operates in a more alert, reactive state. This shows up as generalised anxiety, difficulty settling, racing thoughts, and a feeling of not being able to relax properly.
Add chronic poor sleep, which reduces the brain’s emotional regulatory capacity, and the anxiety common in perimenopausal women is entirely predictable from a physiological standpoint.
Other possible explanations
Not all anxiety in the 40s is hormonal. High sustained stress, significant life transitions, a history of anxiety that has re-emerged, thyroid dysfunction, and inadequate sleep all independently produce anxiety. For many women in midlife, several of these factors are present simultaneously, and the hormonal contribution is adding to an already elevated baseline.
What to do next
You do not have to identify perimenopause with certainty before seeking support. A nurse practitioner at My Clinic can help you understand what is likely driving your anxiety and explore what an appropriate response looks like for your specific situation.