Development of adolescent fertility post-menarche

Follow-up to class discussion 10/15

Metcalf et al (1983) examined the menstrual cycles of 209 females living with their parents and 59 living away from their parents using urine weekly urine analysis over a three month period to establish ovulation by the presence of hormones in the urinary output.  They found that most young women established a regular pattern of ovulatory cycles after 5 years.  The proportion of young women living away form home who had anovulatory cycles was elevated within 5-8 years post menarche, but was not significantly different from the young women living with their parents by 9-12 years after their menstrual cycles began.

Why does it take time?

Although a girl’s normal pubertal development is often considered complete when she experiences her first menstrual period, “sexual maturity is not attained until the onset of regular ovulatory cycles, which may take a number of months to years to accomplish. This maturation process is orchestrated by a neuroendocrine cascade and modified by autocrine and paracrine events in the ovary. The control of these complex relationships takes time and could not be expected to be fully functional with menarche. During the first menstrual months, the hypothalamic-pituitary-ovarian axis is immature, resulting in the secretion of only estrogens from the developing follicles; positive feedback to trigger ovulation develops later. Consequently, estrogen secretion is variable and unopposed by progesterone, which would normally be produced in ovulatory cycles. Estrogen-only primed endometrium often leads to irregular menstrual cycles with variable flow. Surprisingly, most adolescents do well and have few complaints in spite of these anovulatory cycles” (Spence, 1997, p. 173). 

Metcalf, M.G., Skidmore, D.S., Lowry, G.F. & Mackenzie, JA. (1983). Incidence of ovulation in the years after the menarche.  Journal of Endocrinology, 97, 213-219.

Spence, J.E. (1997).  Anovulation and monophasic cycles. Annals of the  New York Academy of Science, 816, 173-176.