Similar to other hormones, the onset of perimenopause and menopause cause the decline in production of testosterone (by at least 50%) in women. Again, hysterectomy with or without removal of the ovaries will cause a more significant decline in testosterone levels . Also, high levels of stress can divert the precursors for testosterone hormone production in women over to cortisol production and create a further reduction. High stress levels can also contribute to symptoms earlier in the perimenopause when a woman is in her late thirties or early forties. This means less energy, brittle hair, less bone and muscle strength, and a diminished sexual drive. A hysterectomy and some prescription drugs can also result in lower levels of testosterone for women .
"Well-defined reference ranges are at the heart of clinical practice and without them clinicians can make erroneous diagnoses that could lead to patients receiving costly, lifelong treatments that they don't need or deny treatments to those who need them," said Shalender Bhasin, MD, of Brigham and Women's Hospital, Harvard Medical School in Boston, MA and lead author of the study. "Our data establish a reference range for testosterone. These data also show that variations in assays is an important contributor to variation in testosterone levels in cohorts from different geographic regions. Clearly we need standardization in all hormone assays."