WHAT DO YOU THINK OF THIS NEW DATA? HOW OLD WERE YOU WHEN YOU CONCEIVED YOUR FIRST CHILD?
Whether you are aware of your incessantly ticking biological clock or not, the absolute last thing that any woman of steadily advancing childbearing age wants to hear when she flips on the morning news shows is: Women lose 90 percent of their eggs by age 30.
Thirty? Life has hardly begun at 30! Gulp.
The hard truth is that decades of research have proved that a woman’s fertility declines over time. But now it appears that the old biological clock may start ticking much earlier—and faster—than once thought.
A study from the University of St. Andrews and Edinburgh University, published last month by PLoS ONE, tracked the human ovarian reserve—or a woman’s potential number of eggs—from conception through menopause. Using a mathematical model and data from 325 women, the researchers found that the average woman is born with around 300,000 eggs and steadily loses them as she ages, with just 12 percent of those eggs remaining at the age of 30, and only 3 percent left by 40.
“That’s a greater percentage of loss at an earlier age than had previously been reported,” says reproductive endocrinologist Robert Stillman, of Shady Grove Fertility in Rockville. “One might be able to argue whether there are 12 percent remaining at age 30 or 22 percent or even 40 percent, but it is still clear that there’s a very rapid loss in the number of eggs available as women age and that the smaller pool of [older] eggs is also more likely to” contain a higher proportion of abnormal eggs, he adds, pointing out that from the mid-30s on, the decline in fertility is much steeper with each passing year.