Study: Female Fertility Chances Drop Sooner

Women in their 20s who are debating how to balance personal and professional aspirations received some unsettling news — fertility appears to decrease at a younger age than believed.

Earlier studies suggested that fertility does not begin to decline until the 30s. But a new study suggests the downward spiral begins at 27. By age 30, fertility can decrease by as much as 50 percent.

"I'm a little worried because I am a young woman and if they're saying 27 is the age now, it makes me feel like I'm in more of a rush," said one 25-year-old woman.

"Even though fertility declines, it is still high enough that women can still conceive in their later 30s. It is just going to maybe take longer or more menstrual cycles for conception to occur," said David B. Dunson, an investigator with the National Institute of Environmental Health Services in North Carolina, which did the study. It was published in the journal Human Reproduction.

Women have known for years that fertility erodes with age, but there is a good deal of confusion about how soon — and how fast — that decline begins.

"There's still women having birth at 40 so I'm not too worried," said one 29-year-old woman.

Overestimating the Clock

Last fall, the American Infertility Association conducted an awareness survey on, a Web site for women. Out of 12,500 respondents, only one answered the survey correctly. Thirty-nine percent said they thought fertility did not begin to drop until after age 40.

"I think that many women know that they have a biological clock but they overestimate the amount of time they have left on that biological clock from five to 10 years," said Pamela Madsen, executive director of the American Fertility Association.

The study also gives new information about the male biological clock. It found that male fertility starts a significant downward slide at 35 and can decline by as much as 40 percent by age 40.

Madsen said she hopes the fertility findings will send a message to those — especially women — who want a career and a family.

"They have to take a pregnant pause in the middle of somewhere and make room for that child. Many times the promotion is going to wait. Unfortunately, our eggs aren't," Madsen said.

A generation of women have been told — in many cases by their doctors — that they could easily start a family later in life. But the study's findings suggest the window of fertility begins closing earlier than many thought.