Aging and infertility in women

Abstract

Female fertility begins to decline many years prior to the onset of menopause despite continued regular ovulatory cycles. Although there is no strict definition of advanced reproductive age in women, infertility becomes more pronounced after the age of 35. A classic report on the effect of female age on fertility found that the percentage of women not using contraception who remained childless rose steadily according to their age at marriage: 6% at age 20 to 24, 9% at age 25 to 29, 15% at age 30 to 34, 30% at age 35 to 39, and 64% at age 40 to 44 (1). Similarly, a sharp decline in pregnancy rate with advancing female age is noted with donor insemination studies (which control for fertility of the male partner and coital frequency) (2) and with assisted reproductive technologies (ART) including in vitro fertilization (IVF). The risk of spontaneous abortion increases with female age (3). According to the 1999 Assisted Reproductive Technology Success Rates, the percentage of clinical pregnancies (gestational sac as imaged with sonography) that failed to result in a live birth rose according to the woman's age: 14% for patients under age 35, 19% at age 35 to 37, 25% at age 38 to 40, and 40% after age 40 (4).