Paleopathology (palaeopathology, traditional British spelling) is the study of ancient health and disease. The field is interdisciplinary, stretching from art history to paleontology and from parasitology to genomics.
Less common symptoms of low estrogen levels include: 1  Thinning hair. 2  Weight gain. 3  Arthritis. 4  Difficulty concentrating.
In addition to menopause, many factors can contribute to a decrease in estrogen levels, including low body fat, extreme exercise, eating disorders, hypogonadism, hypopituitarism, pregnancy failure and polycystic ovarian syndrome, according to WebMD.