If A Woman Freezes Her Eggs, Will Her Future Babies Be Normal?

If you work at such places as Google, Facebook and Apple, your health insurance includes an unusual feature: Coverage for egg freezing. Oocyte preservation, touted as a form of fertility insurance for women who want to delay childbearing, has grown in popularity since its "experimental" label was removed in 2012. But as it moves into the mainstream, is it really producing healthy kids?

Absolutely, says Kate Devine, a reproductive endocrinologist and co-director of research at the nation's largest fertility center, Shady Grove Fertility, which offers egg freezing. The center has over 20 locations in Maryland, Virginia, Pennsylvania and the District of Columbia."The data we have is quite reassuring" about babies produced through egg freezing, she says, "particularly for women for whom the alternative might be not to have a child from their own eggs."

The procedure has been around since the 1980s and has gained popularity in recent years as many millennials delay parenthood. First, a woman's ovaries are stimulated using hormones, then eggs are harvested from the ovaries. (If that sounds similar to in vitro fertilization, or IVF, which is used when a couple has had trouble conceiving, it is.) The extracted eggs are preserved in specialized vials either through a slow-freeze or a flash-freeze process. The eggs are then stored in a cryopreservation facility, or egg bank. Once it's time to use them, they are thawed and fertilized as in the IVF process, and then inserted into the woman's womb. Success is hardly guaranteed: The American Society for Reproductive Medicine estimates that between 2 and 12 percent of frozen eggs yield a baby later.

Oocyte preservation allows women to use eggs from a younger version of themselves - versions who, perhaps, haven't yet had cancer treatment, found a long-term partner or been ready for pregnancy.

According to Devine, it's best for a woman to freeze her eggs by the time she's 35 years old to ensure the highest rate of success.

So what about the babies produced with frozen eggs? Because the technology is so new, there isn't a lot of data. There's no registry of births achieved using frozen eggs, and very few studies have focused on outcomes beyond pregnancy.

One 2009 study that tracked 900 babies born using frozen eggs found no difference in the rate of birth abnormalities compared with the rate for babies born with fresh eggs. Most other studies have been much smaller, tracking just a handful of babies; they show outcomes similar to babies born using traditional IVF.

Tracking usually ends in infancy. Although Devine estimates that tens of thousands of babies have been born using the procedure, there's no way of knowing how they're doing as they grow up.

"Women really want to know, 'Am I going to have a baby from my eggs if I freeze them?' " Devine says.

Perhaps the better question is "How will these babies fare once they go home?"

Learn more: reproductivefacts.org (search for "egg freezing").

Special to The Washington Post