Self-Assessment Questions

12. Puberty in girls

• A mother brings her 14-year-old daughter to see you in clinic. She is concerned because her daughter started her menstrual periods almost 2 years ago, and is still reporting heavy and irregular bleeding even with a healthy diet, good sleep and no medical conditions. The mother demands an explanation, as she remembers that it only took 9 months for her own periods to become regular. Explain to this worried mother the physiologic basis for the daughter's irregular menstrual periods. What additional information would you tell her to ease her fears that her daughter is abnormal?

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  Correct answer:
  During the first years after menarche occurs, many of the menstrual cycles do not result in ovulation. This is due to incomplete maturation of the hypothalamus and imperfect hypothalamic response to feedback by estrogen, a hormone secreted by the ovaries. Progesterone is normally secreted by the corpus luteum, the structure that is left in the ovary following ovulation. Because the daughter's reproductive system has not fully developed appropriate estrogen responses, many of her cycles may not result in ovulation. Her bleeding patterns continue to be irregular due to a lack of corpus luteum formation and continuous exposure of the inner lining of the uterus, the endometrium, to estrogen. This process, while a nuisance, is very common and normal. The vast majority of girls will have regular, ovulatory cycles by 5 years after the onset of menstruation, so it may take longer than the mother had anticipated.