There is no universal definition of advanced reproductive age in women, in part because the effects of increasing age occur as a continuum, rather than as a threshold effect. Fertility clearly declines with advancing age, especially after the mid-30s, and women who conceive are at greater risk of pregnancy complications [1-4]. However, studies have generally observed that most women over 45 years of age [5-10] or over 50 years of age [1-3,11] have good pregnancy outcomes and are able to cope with the physical and emotional stresses of pregnancy and parenting . With use of assisted reproductive techniques (ART), births have been reported to several women 66 years of age and one woman age 70 years of age. The oldest woman to achieve a naturally conceived pregnancy was 57 years of age.
The effects of a woman's age on fertility and pregnancy will be reviewed here. Reproductive concerns related to advanced paternal age are discussed separately. (See "Effect of advanced paternal age on fertility and pregnancy".)
Advancing age is associated with prolongation in the average time for achieving conception . Fecundability (ie, the probability of achieving a pregnancy in one menstrual cycle) begins to decline significantly in the early 30s (about age 32 years), with a more rapid decline a few years later (about age 37) . Several lines of evidence from both natural and assisted cycles support this finding:
●In historical cohorts in whom deliberate fertility control was rare and conception did not generally precede marriage, the rate of involuntary childlessness in women who married at age 20 to 24, 25 to 29, 30 to 34, 35 to 39, and 40 to 44 was 6, 9, 15, 30, and 64 percent, respectively . In other similar groups, the average age of last birth ranged from 40.9 to 45.7 years and 87 to 99 percent of women were infertile at age 45 [15,16].
●A large well-designed study reported the probability of clinical pregnancy following intercourse on the most fertile cycle day in women of average fertility aged 19 to 26 years, 27 to 34 years, and 35 to 39 years was approximately 50, 40, and 30 percent, respectively, if the male partner was the same age .