Sistemas

Human Reproduction Update, Vol.11, No.3 pp. 261–276, 2005 Advance Access publication April 7, 2005

doi:10.1093/humupd/dmi006

Fertility and ageing
ESHRE Capri Workshop Group*
* A meeting was organized by ESHRE (Capri, September 4 –5, 2004) with financial support from Institut Biochimique SA to discuss the above subjects. The speakers included D.T.Baird (Edinburgh), J.Collins (Hamilton),J.Egozcue (Barcelona), L.H.Evers (Maastricht), L.Gianaroli (Bologna), H.Leridon (Paris), A.Sunde (Trondheim), A.Templeton (Aberdeen), A.Van Steirteghem (Bruxelles). The discussants included: J.Cohen (Paris), P.G.Crosignani (Milano), P.Devroey (Brussels), K.Diedrich (Lubeck), B.C.J.M.Fauser (Rotterdam), L.Fraser (London), A.Glasier (Edinburgh), I.Liebaers (Brussels), G.Mautone (Lugano), G.Penney(Aberdeen), B.Tarlatzis (Thessaloniki). The report was prepared by J.Collins (Hamilton) and P.G.Crosignani (Milano).

The late 20th century trend to delay birth of the first child until the age at which female fecundity or reproductive capacity is lower has increased the incidence of age-related infertility. The trend and its consequences have also stimulated interest in the possible factors in thefemale and the male that may contribute to the decline in fecundity with age; in the means that exist to predict fecundity; and in the consequences for pregnancy and childbirth. In the female, the number of oocytes decreases with age until the menopause. Oocyte quality also diminishes, due in part to increased aneuploidy because of factors such as changes in spindle integrity. Although older maleage affects the likelihood of conception, abnormalities in sperm chromosomes and in some components of the semen analysis are less important than the frequency of intercourse. Age is as accurate as any other predictor of conception with assisted reproductive technology. The decline in fecundity becomes clinically relevant when women reach their mid-30s, when even assisted reproduction treatmentcannot compensate for the decline in fecundity associated with delaying attempts at conceiving. Pregnancies among women aged > 40 years are associated with more non-severe complications, more premature births, more congenital malformations and more interventions at birth.
Key words: ageing/demographics/fecundity/fertility/infertility

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Introduction
Two fertility trends of the 21st century are already evident in the Western countries; women are having fewer children and they are delaying births to a later age than in previous centuries (Daguet, 2002). Populations are ageing at a rate that is without precedent because not only are there fewer children, but the decline in mortality rates at age .60 years has also increasedthe number of older people. A further consequence is that women who choose to delay their attempts at conception may encounter delays and/or disappointment due to decreased fecundity. Decreased fecundity with increasing female age has long been recognized from demographic and epidemiological studies, which consistently found that fertility declined beginning as early as the middle of the thirddecade (Figure 1) (Menken et al., 1986; Leridon, 2004). The biological basis of this decline in fecundity with increasing female age appears to involve several factors; germ cells in the female are not replenished during life, attrition and utilization of follicles leads to a decline in the number of oocytes from birth to menopause, the quality of existing oocytes diminishes with age and on anaverage, intercourse frequency declines with age.

The demographic fertility trend and the individual woman’s fecundity are usually studied by different methods. Demographic studies of fertility involve indicators such as the fertility rate, average age at birth and time to pregnancy. However, in the management of infertile couples, it is hoped that the chronological age of the individual does not...