Estrogen is considered to stimulate serotonin, a brain chemical that improves mood. Estrogen shortage can lead to a decrease in serotonin, which can lead to mood swings or sadness. As your body produces more estrogen, your serotonin levels will increase. The link between estrogen and mood has to do with more than just serum levels of the hormone. Serotonin is found not only in the brain but also in other parts of the body, such as the gut and the spinal cord. Thus, changes in estrogen status can have effects on the way you feel everywhere in your body, not just in the brain. For example, when estrogen levels are high, menopausal women tend to experience less anxiety and depression than pre-menopause women of a similar age. Women's emotions often change during their menstrual cycles. The lowest levels of estrogen occur at the start of menstruation and the highest levels at the end. Between these two extremes, there is a gradual rise in estrogen that causes typical female feelings such as sensitivity to pain, warmth, and pleasure. During perimenopause, the body begins to show signs of aging without the onset of menopause, such as changes in the uterus, breasts, and ovaries. In postmenopause, the absence of menstruation and fertility signals, the body fully transitions into menopause.