How long should a woman wait to freeze her eggs?

Emily DeMarco in Science:

EggIn 2012, the American Society for Reproductive Medicine announced that it was no longer “experimental” for a woman to freeze her eggs simply because she wanted to wait to have a child. Since then, demand for the procedure has skyrocketed, even though its costs remain high. Now, scientists say they have figured out—taking economic and biological considerations into account—the best age for women to freeze their eggs if they want to get pregnant as late in life as possible. Two main factors determine when it’s best to freeze human eggs: how viable those eggs will be when thawed and how much it’s going to cost. The longer a woman waits to freeze her eggs, the less likely they are to result in a live birth. Yet, older women get more bang for their buck by freezing their eggs, because the procedure benefits them most; young women potentially waste money freezing their eggs because they’ll still likely be quite fertile a few years down the line.

…Fertility rates, however, are most strongly influenced by the age of a woman’s eggs. As a result, the nearly 52% probability of a successful pregnancy using those eggs frozen in time at age 37 is lower than what many women and their doctors consider acceptable. According to the study, most women would have to freeze their eggs by age 34 to have at least a 70% chance of live birth. Considering the researchers found that egg freezing provided the most improvement in live birth rates over not freezing after age 30, “we feel the sweet spot for those electing to freeze is age 31 to 33,” says co-author Tolga Mesen, an obstetrician-gynecologist at the Fertility Clinic at the University of North Carolina, Chapel Hill.

More here.