Reproductive Age in Women

In today’s society, the first pregnancy delay phenomenon led to increased infertility rates associated with maternal age (Stephen and Chandra, 2006). Thus, a high percentage of couples depend on assisted reproductive techniques to achieve a pregnancy. Increasing infertility incidence correlated with female age is primarily caused by changes in ovarian function, otherwise attested by decreasing ovarian reserve. Ovarian reserve may be defined by the number and quality of oocytes and follicles in both ovaries existing at a certain age. The decline in the number of follicles dictates the installation of irregular periods and menopause, while their low quality results in decreased fertility (TeVelde and Pearson, 2002).

Variability of reproductive age

As for the menopause, there is a substantial individual variability in terms of female age, this ranging between 40 and 60 years, with a mean age of 51 years. This variation was found to be rather constant over time in the general population (Morabia and Constanza, 1998). Female fecundity is considered to decrease after age 31 years, a decrease that may accelerate after age 37 years, leading to sterility in an average age of 41 years. As for the menopause, fertility decline rate may vary considerably between women of the same age. This means that a woman at the age of 35 years may either be close to natural sterility or have normal fertility comparable to the age of 25 years. Correct prediction of menopause provides important information about women’s reproductive life and helps in preventing future infertility.

What is ovarian aging?

Ovarian aging is defined by the reduction of the quantity and quality of oocytes in the ovaries. Although the average age of menopause is 51 years, about 1 in 10 women reach menopause at age 45 and 1 in 100 women reach menopause before the age of 40 years. It was established that fertility is reduced 13 years before menopause, for example 1 in 10 women will have reduced fertility around the age of 32 years (Nikolic Templeton, 2003).

Prediction of ovarian reserve

A series of tests of ovarian reserve were used to predict ovarian aging or insufficient ovarian reserve. Thus, knowing the ovarian aging process involves ovarian reserve testing before initiating treatment with assisted human reproduction techniques. Woman’s age remains a predictor at first choice. Availability of tests that provide solid information on ovarian reserve at a certain age gives physicians the opportunity to provide individualized treatment plan. For example, older women who are discovered a  high level ovarian reserve  will be recommended for assisted reproduction treatment, while young women with a low ovarian reserve may receive indication of assisted human reproduction procedures earlier than is provided in standard protocols.

References:

• Morabia A and Costanza MC. International variability in ages at menarche, first livebirth, and menopause. World Health Organization Collaborative Study of Neoplasia and Steroid Contraceptives. Am J Epidemiol. 1998;148:1195-1205.
• Nikolaou, D. and Templeton, A. (2003) Early ovarian ageing: a hypothesis. Detection and clinical relevance. Hum. Reprod., 18, 1137–1139
• Stephen E, et al. Declining estimates of infertility in the United States: 1982-2002. Fertility and Sterility 2006;86(3):516-523
• TeVelde, E.R. and Pearson, P.L. (2002) The variability of female reproductive ageing Hum. Reprod. Update., 8, 141–154.