Even though most women are aware of this fact, many underestimate the extent of the decline in fertility with age. Some women think that because they are in good health and take care of their body, they are not as susceptible to the effects of age on fertility. Perhaps that’s due to maternal optimism. But on a practical note, such a misconception can make it harder to conceive later in life. It is estimated that a woman aged 25 or younger take two to three months to get pregnant, whereas it takes a woman aged 35 or older six months. This is also born out in women having artificial insemination, with a 25-year-old or younger having an 11 percent monthly chance of pregnancy while a woman 35 or older has only a 6.5 percent chance. There are several reasons for this decline in fertility.
- Dr. Seang Lin Tan, MD
The simple answer is yes: rates have been rising over the long term. We find a little more complicated answer in two recent studies. One by the World Health Organization (WHO) shows that worldwide rates of infertility have remained essentially static over the past 20 years. A 2012 Canadian study indicates that rates in this country appear to be on the rise.
Studies can show different results for different reasons. For instance, the WHO study used a definition of infertility as a couple attempting to get pregnant over a five-year period. Most doctors, including myself, consider a one-year period to be a clear indicator of infertility. Should we throw the WHO study out the window? Not necessarily, perhaps just take it with a grain of salt.
- Seang Lin Tan, MD