Not necessarily—menopause is primarily characterized by hormonal fluctuations. During perimenopause, estrogen levels may even be temporarily higher than before, before they drop permanently. It is not until postmenopause that estrogen levels drop to a permanently lower level.
Many typical menopausal symptoms, such as hot flashes, sleep disturbances, or mood swings, are caused not only by low estrogen levels but also by an imbalance between the two female sex hormones, estrogen and progesterone. The term “estrogen deficiency” is therefore not always entirely accurate, but it is frequently used as a general term for the hormonal changes that occur during menopause.