Rachel Lehmann-Haupt was 37 when she froze her eggs, a process technically known as oocyte cryopreservation. She knew it wouldn't guarantee her fertility. But the San Francisco writer had just ended a relationship and knew she wanted kids.
"I wanted to buy biological time," said Lehmann-Haupt, now 40 and still childless. "The older I get, the more I think, 'Maybe the eggs I froze will be my route to motherhood.' "
Women lose much of their natural fertility between 35 and 40, says Dr. Nicole Noyes, co-director of the Oocyte Cryopreservation program at the New York University fertility center and Lehmann-Haupt's doctor. As women age, the quality of their eggs also declines, which raises the chance of miscarrying, Noyes said.
Though women can't make their eggs healthier, they can keep them from getting older. The process, which takes two to six weeks, involves taking fertility medication to mature multiple eggs in the ovaries. Then the eggs are extracted from the woman, gently dehydrated and stored in liquid nitrogen. When she's ready for pregnancy, her eggs can be thawed, fertilized and transferred to the uterus as embryos.
For women whose medical treatments present a risk of infertility, particularly cancer patients, egg freezing is a way to protect the possibility of a pregnancy. More controversially, the procedure is also marketed as an option for healthy women who aren't ready to have children but hope to in the future.
Critics say the best chance of having a baby is doing it naturally when a woman is younger than 35. They worry that egg preservation will give a woman false confidence, that she may make plans based on preserved eggs that fail in the future.
But Noyes says that's not what's happening. "They're 36, 37 years old, and they're panicking," she said.
One concern is that egg freezing is still in the early stages and the oocytes can be damaged during freezing and thawing. The American Society for Reproductive Medicine calls it "experimental" and warns that until there's more "proven scientific information," healthy women shouldn't use it as a way to defer reproduction.
About half of fertility clinics offer egg freezing, said Glenn Schattman, associate professor of reproductive medicine at Cornell University's Weil Medical College in New York and a co-author of the ASRM guidelines. A 2009 study showed 936 babies worldwide had been born from frozen eggs with no increase in birth defects.
In theory, eggs may be stored indefinitely, but shelf life is difficult to determine. And no one knows how freezing the egg affects the long-term health of the baby.
It's also expensive. Though prices vary by clinic, it costs about $9,500 to freeze eggs. A private company may have an additional charge of $1,000 to $3,000, said Noyes. The thaw cycle — when the eggs are taken out of liquid nitrogen and fertilized — is about $3,500 to $5,000.
Still, egg freezing can ease pressure for some women. Lehmann-Haupt, who wrote In Her Own Sweet Time: Unexpected Adventures in Finding Love, Commitment and Motherhood about her experience, remains hopeful.
But if her own eggs fail? "I think I'm slightly in denial," she admitted. "I'd be pretty devastated if I can't have a child or adopt."