Abnormal vaginal bleeding in adolescents.

1. Susan Hayden Gray, MD* 2. S. Jean Emans, MD† 1. *Department of Pediatrics, Boston Medical Center, Boston University School of Medicine, Boston, Mass 2. †Division of Adolescent Medicine, Children's Hospital Boston, Department of Pediatrics, Harvard Medical School, Boston, Mass After completing this article, readers should be able to: 1. Describe normal and abnormal patterns of vaginal bleeding in adolescents. 2. Discuss the differential diagnosis of abnormal vaginal bleeding in adolescents. 3. Outline a strategy for diagnosis and management of abnormal vaginal bleeding. Many young women experience irregular or heavy vaginal bleeding in the course of their development. In most cases, the abnormal bleeding is due to anovulation and immaturity of the hypothalamic-pituitary-ovarian feedback mechanisms. However, abnormal bleeding may be the presenting sign of multiple medical illnesses that require long-term treatment and follow-up, and pediatricians must recognize and exclude other potential causes of bleeding. It is essential to review normal menstrual physiology before discussing abnormalities. An ovulatory menstrual cycle is comprised of three phases: follicular, ovulatory, and luteal. The follicular phase of the menstrual cycle typically lasts about 2 weeks but may vary from 7 to 21 days or longer. In the follicular phase, the hypothalamus releases pulses of gonadotropin-releasing hormone, stimulating the pituitary to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH and LH stimulate the development of ovarian follicles and the synthesis of steroid hormones. FSH increases the number of granulosa cells in the ovary, promotes estrogen secretion by increasing aromatase, and increases the number of FSH receptors on the granulosa cells. LH stimulates the ovarian theca cells to enhance the secretion of both estrogen and androgens, which are converted to testosterone and estrogen in ovarian and peripheral tissue. Rising estrogen concentrations stimulate proliferation of the endometrial lining and exert a negative feedback effect on FSH. They also exert a positive feedback effect on LH, resulting in the midcycle LH surge that stimulates ovulation. Both negative and positive feedback mechanisms must be functional for ovulation to occur. At ovulation, the ovary releases an oocyte, and the remaining ovarian follicle becomes …