When Apple and Facebook announced last year that they would cover elective egg freezing, people started talking more about this new-ish procedure. The ability to “put motherhood on hold” by preserving your eggs for future use seems like an alluring way to ease the baby-making pressure for couples who are meeting and marrying later in life.

But a quick search into elective egg freezing—a.k.a. oocyte cryopreservation—reveals confusing (and often conflicting) information. For starters, the women choosing to go through this process are not all workaholics looking to delay motherhood because of their taxing schedules. In fact, in one NYU survey, 88 percent of women who froze their eggs cited the lack of a partner as the reason for delayed childbearing.

Motivations aside, one 2010 study found that at least 50 percent of in vitro fertilization (IVF) clinics in the U.S. offered elective egg freezing.The status of oocyte cryopreservation in the United States. Rudick B, Opper N, Paulson R. Fertility and sterility, 2010, Jun.;94(7):1556-5653.”>The status of oocyte cryopreservation in the United States. Rudick B, Opper N, Paulson R. Fertility and sterility, 2010, Jun.;94(7):1556-5653. And since the label “experimental” was lifted from the procedure two years ago, that number has probably grown. That means you’re more likely to find a place to freeze your eggs—but first you need to know the facts so you can decide if it’s the right choice for you (and your partner, if you have one).

The Link Between Age and Cost

What You Should Know About Egg Freezing

While experts’ opinions differ, according to one study, the best age to freeze your eggs is between 31 and 33.Optimal timing for elective egg freezing. Mesen TB, Mersereau JE, Kane JB. Fertility and sterility, 2015, Apr.;103(6):1556-5653.”>Optimal timing for elective egg freezing. Mesen TB, Mersereau JE, Kane JB. Fertility and sterility, 2015, Apr.;103(6):1556-5653.

“Below age 31, the success rates are high,” says Tolga Mesen, M.D., a doctor at UNC Fertility Clinic who co-authored the study, “but the success rate is also high if you try to conceive naturally.” Thirty-two seems to be the point at which egg freezing makes a significant difference in your potential to get pregnant later in life.

In practice, the average age tends to be late 30s, says Elizabeth Fino, M.D., a reproductive endocrinologist from NYU Langone Medical Center, who’s seen the age of her patients slowly drop from 38 or 39 in 2010, to 36 or 37 in 2014. She encourages women to think about the procedure at a younger age. “If you’re going to invest that amount of money, you want to make sure you’re in the best success rate group.”

Egg freezing hits a place in our hearts as we contemplate what we want to do with our life.

And is it quite an investment. “In general, the cost will be between $10,000 to $15,000 to freeze your eggs,” says Ilaina Edison, CEO of Extend Fertility, a national fertility center. That price—which has dropped in recent years—is an estimate for a woman about 35 years old, and includes a hormone treatment, one cycle of egg retrieval, and one year of egg freezing. After that, expect to fork out $1,000 to $1,200 per year to store the eggs, Edison says.

The number of eggs harvested depends on the individual, but in general experts recommend putting away 15 to 20. For women younger than 35, sometimes a single cycle will produce that number. But as women age, more cycles are needed to harvest a viable number of eggs. That means another round of hormones and another egg retrieval procedure. So a woman closer to 40 may need two to three cycles in order to retrieve the number of eggs her doctor has recommended—and that could cost $15,000 to $25,000, Edison says. “Egg freezing is expensive, which is why most women tend to be older.”

Plus, unless you work for Apple or Facebook, the cost is likely out of pocket. The majority of people pay either with loans or through other forms of financing, Edison says. Others use what Angeline Beltsos, M.D., the medical director for the Fertility Centers of Illinois, calls “grandparents’ insurance”—their parents help cover the cost.

The First Steps in Egg Freezing

The first (and perhaps most important) step is a consultation. During this time, you’ll likely discuss your ovarian reserve—that is, about how many eggs are available based on your natural fertility.

You might recall from high school sex ed that a woman is born with all of her follicles—the fluid-filled spheres inside which eggs mature. Unlike men, who regularly produce new sperm, women have about one million follicles at birth—and that’s it. As a woman ages, her fertility naturally declines, a process called “loss of ovarian reserve.” No single test exists to answer with complete certainty how many eggs are available, but through blood tests or an ultrasound, a doctor can make a pretty good estimate.

Is having a baby the most important thing to you, or is falling in love and having a baby with a partner more important?

You may also discuss more personal aspects of the future: Is having a baby the most important thing to you, or is falling in love and having a baby with a partner more important?

For many, egg freezing removes that “I must meet someone and marry and pop out babies” pressure women may start to feel at some point in their 20s. Taking care of your eggs now means you don’t have to worry about it in the future (to some degree), Fino says.

Yet despite feeling empowered, as about half the women in the NYU survey reported, there are also emotional drawbacks. “Egg freezing hits a place in our hearts as we contemplate what we want to do with our life,” Beltsos says. “It’s a reminder to some women that they don’t have someone.” And though egg freezing may not be emotionally trying, the IVF a woman faces down the road when she’s ready to use the preserved eggs can be. It’s a lot to think through.

The Egg Retrieval Procedure

If freezing your eggs is the right choice for you, you’ll start a hormone treatment to stimulate egg production. This typically involves oral doses, subcutaneous injections to the abdomen, and frequent endocrinologist visits to make sure everything is going smoothly.

During this time, there is a small chance (Fino estimates 1 to 2 percent) of ovarian hyperstimulation syndrome (OHSS). Because of the extras hormones, the ovaries can become swollen and painful. Often the syndrome resolves on its own, but at worst, you would need to be hospitalized.

Assuming there aren’t any complications, at the end of 10 to 14 days, you undergo an egg retrieval procedure, which takes about 30 minutes and requires sedation. Usually a method called transvaginal ultrasound aspiration is used. Basically, after the follicles are identified, a thin needle is inserted into an ultrasound guide, which pierces the vagina and enters the follicles to retrieve the mature eggs. A suction device is located on the other end of the needle, and one by one, the follicular fluid is drained and the egg is retrieved. Risks are small, but you may experience soreness for up to a week after the procedure.

After the eggs are collected, they’re frozen using either a slow-freeze method or a fast-freeze process called vitrification. Freezing is complicated because the eggs have a high water composition, and if ice forms, they’re damaged. So how do you freeze a watery egg without creating ice? Both methods replace intercellular water with cryoprotectants—chemicals that help prevent ice crystals from forming—but in different ways. Slow-freeze methods, which were more common until recently, introduce cryoprotectants gradually, as the eggs are cooling. Vitrification, on the other hand, uses high initial concentrations of cryoprotectants in combination with faster cooling so that ice crystals don’t have time to form. Because of the reduced risk of ice, some clinics now use this method exclusively.

Frozen eggs are held at sub-zero temperatures at a fertility center or egg bank until you decide to use them. The eggs are good for at least a decade—and probably longer—as long as they are stored correctly, experts say.

And if you move, there are companies that specialize in transporting cryopreserved material—at the expense of around $1,000, according to one company. There’s also risk involved since something could happen in shipment that makes the eggs unusable.

Maybe Baby

Great as it may sound, egg freezing doesn’t guarantee the ability to have a baby on demand. “People think frozen eggs are as good as fresh eggs, and that’s not true,” says Kutluk Oktay, M.D., an expert in fertility preservation. “When you preserve eggs, you preserve the possibility of getting pregnant.”

While the American Society for Reproductive Medicine says a single thawed egg has a 2 to 12 percent chance of yielding a baby, doctors always thaw a batch of eggs for IVF, Fino says, which increases the chances of pregnancy.

Still, success rates vary depending on the age at which the eggs were retrieved and the age at which a woman decides to use them. Fino gives a 40 to 50 percent pregnancy rate from using eggs frozen at age 35 or younger. Both Oktay and Mesen also have online calculators (here and here, respectively) that provide estimates based on data from separate studies.Age-specific probability of live birth with oocyte cryopreservation: an individual patient data meta-analysis. Cil AP, Bang H, Oktay K. Fertility and sterility, 2013, May.;100(2):1556-5653. Optimal timing for elective egg freezing. Mesen TB, Mersereau JE, Kane JB. Fertility and sterility, 2015, Apr.;103(6):1556-5653.”>Age-specific probability of live birth with oocyte cryopreservation: an individual patient data meta-analysis. Cil AP, Bang H, Oktay K. Fertility and sterility, 2013, May.;100(2):1556-5653. Optimal timing for elective egg freezing. Mesen TB, Mersereau JE, Kane JB. Fertility and sterility, 2015, Apr.;103(6):1556-5653.

But just because you freeze eggs doesn’t mean you’ll use them. When you decide to try to have a baby, even if you’re 40 and have a boyfriend or husband, your doctor may suggest trying naturally for a few months. If that doesn’t work, your doc may still recommend going through IVF with fresh eggs because there’s a finite number of frozen eggs that can be thawed for pregnancy, and you may want a second child, Fino explains.

Oktay adds that because elective egg freezing is relatively new, there could be other unknowns. “We are 99.9 percent sure we won’t have any issues with these children. But we need another 10 to 20 years of data to say definitively that all of these children are healthy and don’t have increased problems compared to naturally born babies.”

The Takeaway

“The reality is, we’re born with our eggs. We can’t make anymore,” Beltsos says. “And by the time you want to start a family, if you don’t have eggs—you’re out of luck. That’s why you at least want to consider freezing.”

Fino adds that egg freezing shouldn’t become another stress, rather it’s a chance to take control of your reproductive future. In the end, the biggest upside to elective egg freezing is that when a woman is finally ready to get pregnant, she might be able to do just that.