According to a recent study from researchers in Scotland, by the time women hit 30, up to 95 percent of them have already lost about 88 percent of their eggs—a full five years earlier than the "fertility drop off" point women commonly worry about reaching in their mid-30s.
Published online January 27, 2010, by the Public Library of Science, a peer-reviewed science journal, the study looked at 325 women of different ages in the US, UK, and other parts of Europe. Not only was the news not good for women at age 30, by age 40, the vast majority of women had only 3 percent of eggs remaining.
Researchers also noted a dip in the quality of eggs as the women aged. Commenting on the study to ABC News, Dr. Marie Savard, a Good Morning America medical contributor, noted that "Women lose eggs a lot faster than we thought."
Your biological clock will always tick, but there are certain factors under your control that can have a big impact on your fertility. Stopping smoking, keeping your weight down, and controlling stress may all slow fertility loss, recommends Savard. Women who have more pregnancies tend to be fertile longer and some women may be simply born with more eggs than others.
Still, the takeaway message from studies like this one may be simple. "[Conceiving is] much more difficult [as you age]. Even all those assisted reproductive techniques are challenges," said Savard. "Women should have children earlier, if possible. Healthy women in their late 30s and early 40s who think they can postpone pregnancy may be jeopardizing their chance of conceiving," she added.