Excluding pregnancy, hyperprolactinemia accounts for
approximately 10-20% of cases of amenorrhea. Women
with oligomenorrhea, amenorrhea, or galactorrhea should
have a serum prolactin measured.
Polycystic Ovary Syndrome
Polycystic ovary syndrome (PCOS), the most common cause of infertility, is seen in 6-10% of women of reproductive age. Presenting symptoms include irregular menstrual periods, acne, facial or body hirsutism, male-pattern alopecia and occasionally weight gain. PCOS is also associated with insulin resistance and obesity. It was once felt that all women with PCOS are overweight or obese; however, it is now known that, in fact, up to 15-40% of women with this condition are of normal body weight and may even be lean or underweight. This condition generally presents with a history of irregular and unpredictable inter-menstrual intervals beginning at menarche. Women will usually give a history of having always had irregular menses, generally occurring between every 35 days and every few months. Occasionally women will note that their periods were more regular when they were younger, but as they got older (and gained weight) their menses became less predictable. PCOS is characterized by anovulatory menstrual cycles (consequently irregular) and high levels of testosterone. Incidentally, most assays for testosterone consider a value less than 80 ng/dL to be normal for a post-pubertal female; however, a value greater than 50 ng/dL should be considered abnormal in a woman who is experiencing other symptoms consistent with PCOS. While other laboratory abnormalities, including an elevated LH/FSH ratio, are often seen in PCOS, to make a definitive diagnosis, a woman must have irregular menses and an elevated testosterone. It is also important to understand that PCOS is often a diagnosis of exclusion because a number of other endocrine abnormalities can present in a similar fashion with almost identical laboratory findings. These other disorders, including Cushing?s syndrome and a variety of adrenal abnormalities, need to be ruled out, as the treatment interventions are entirely different.