Have you ever heard that oft-cited statistic that only one in three women between the ages of 35 and 39 become pregnant after a year of trying?

Perhaps less often cited is the fact that this statistic is based on data almost three-and-a-half centuries old.

Much of what we hear about women’s declining fertility comes from a study that was published in 2004. A decade-old study is no cause for alarm. But that study is based on French birth records from 1670 to 1830.

But newer data seem to be telling a different story about women’s fertility. One study followed 770 European women as they were trying to become pregnant. After a year, 82 percent of women between 35 and 39 became pregnant while trying twice per week, only four percentage points under the rate for women between the ages of 27 and 34.

A 2013 study examined data from more than twenty-eight-hundred Danish women and found that 80 percent of women ages 38 and 39 were able to get pregnant within a year of trying.

Simply getting pregnant isn’t the only concern of older mothers, who may worry about the health of their fetuses. But studies also show that 99 percent of babies born to 35-year-old women and 97 percent of babies born to 40-year-old-women are chromosomally normal.

Doctors also say there are measures you can take to have a healthy pregnancy. Women should start increasing their intake of folic acid, even before they start trying for a baby. Folic acid helps build healthy cells, which is important at the earliest stages of fetal development. Folic acid also decreases the risk for neurological disorders such as spina bifida. Monitoring when you ovulate also may help you become pregnant more easily.

Finally, experts say, avoid worrying. Your age may be less of a ticking time bomb than you think.