As we age, many aspects of our body and health change. This includes many subtle but important changes in the reproductive process for women. The impact of age on fertility is becoming an increasingly significant issue as more women choose to delay childbearing until later in life.
The most important factor for all women and their partners to understand is that a woman’s reproductive potential declines with age (fig. 1). When this decline begins, often around age 30, most women do not even realize that it is happening. Even though a woman may continue to have regular menstrual cycles until she reaches menopause, the ability to have children may be lost 7 to 12 years prior to menopause. Nearly one third of couples that include a woman age 35 or older will have problems with fertility. And less than 30% of women over age 40 are able to become pregnant naturally. In addition to increased difficulty with fertility, a woman’s chance of having a miscarriage also increases with age (fig. 2).
fig.1 – For most women, the ability to conceive and carry a baby to term begins to decline at age 30, and declines most rapidly after age 40.
fig. 2 – Women are more likely to have a miscarriage as their age increases.
The main factor associated with infertility in women is egg quality. As women age, their egg quality declines (fig. 3).
fig. 3 – The percentage of eggs with abnormal chromosomes increases as a woman ages.
fig. 1: Abstracted from National Bureau of Health Statistics, 2000
fig. 2: Gindoff and Jewelweicz, Fertil Steril 46:989, 1986
fig. 3: Munne S, Cohen J. Hum Reprod Update 4:842, 1998