Fertility and ageing

Abstract

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 the female 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 male age 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 treatment cannot 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.

Between a rock and a hard place: The reasons why women delay childbearing

“…[3,17,20,24] However, despite significant medical advances in technology, ARTs cannot fully compensate for age-related fertility decline. [27,28] Given the relatively low success rates of IVF for women in their late 30s and early 40s, and estimated success rates of between 2% and 12% using cryopreserved eggs [29] these advanced reproductive technologies may be giving women of AMA false hope about their ability to safely delay childbearing. [10][11][12][13] Some have suggested that, in relying on ARTs to extend the reproductive lifespan, women may indeed be "sleepwalking into infertility".…”

Analyzing the risk factors for a diminished oocyte retrieval rate under controlled ovarian stimulation

“…This study revealed that the oocyte retrieval rate declines significantly with age. There is an evident gradual decline in female fecundity with age, particularly noticeable in those who are older than 30 years, accelerating between the ages of 35 and 40, and reducing to almost zero by 45 years 4, 5. There is also a decrease in the ovarian reserve with age, caused by the decreased number of oocytes and the concomitant increase in the rate of oocyte aneuploidy and subsequent reduced reproductive potential 6.…”

Maternal age and in vitro culture affect mitochondrial number and function in equine oocytes and embryos

“…However, endometrial degeneration is probably not the primary contributor to the age-related decline in mare fertility. Embryos flushed from the oviducts of mares $20 years of age have been reported to undergo delayed cleavage and to contain fewer cells than those from younger mares (Carnevale and Ginther 1995), analogous to the situation in older compared with younger women (Baird et al 2005). Combined with studies demonstrating that embryos from mares .18 years show lower survival rates than embryos from mares ,6 years after transfer to young recipients (Ball et al 1989), this indicates that the loss of developmental potential is intrinsic to the ovulated oocyte or arises during very early (intra-oviductal) embryo development.…”