Age does predict egg quality with greater accuracy than any other factor. That’s why IVF success rates are usually sub-categorized by the woman’s age.
The oldest patient I helped achieve pregnancy through a fresh IVF cycle with her own eggs was 45 when she delivered; a colleague of mine diagnosed a (very surprised) 51 year old with “stomach flu” as being in her second trimester. So there is a lot more to fertility success than age. But it’s an inescapable variable, and such stories remain the exception.
But let’s dig a little deeper.
Studies have shown that cycle fecundity – the odds of getting pregnant in a given cycle – starts to fall from the age of 27 years.
Now, don’t freak out too much about that. The number 27 is a statistical average. In fact, for nearly all women, when fertility does start to change, it doesn’t fall very fast at all. Most women will have no troubles with egg quality when they are less than 35 years old. (If you’re young, and have been told that you have egg quality issues, you may wish to look into the tests associated with premature ovarian failure.)
Once they’re 35 years old, a few women will have difficulties with egg quality. But most won’t. In fact, most women can count on good eggs until at least 38 – but there are enough 35-year-old women with egg quality issues that we can start to make generalizations based on age. As a population, when comparing women over 35 to those under 35:
- It takes longer to get pregnant
- There’s an increased chance of having an early miscarriage
- There’s an increased risk of Down’s syndrome
Again, for most women, these effects will not be immediately apparent at first.
However, by age 38, most women will be affected by the realities of decreasing egg quality. The average age beyond which a woman will be unable to have a healthy pregnancy is 42.
Again, “42″ is a statistical number only: there are many women who can achieve pregnancies at age 43 or older. However, these pregnancies are matched by an equal number of women younger than 42 who cannot.
The bottom line is this: over age 38, it is reasonable to assume that age will be playing a role in egg quality. It may not matter, for example, if a woman at age 32 decides to put off her family for another two years. But for someone 40 years old, two years matters.