Which means there are usually not sufficient circumstances to guage and provide you with strong information on the percentages of success. It additionally implies that many clinics that freeze eggs do not need expertise thawing them.

Eggs are trickier to thaw efficiently than embryos, specialists mentioned. An egg is one cell, the biggest cell within the physique, and accommodates loads of fluid and a construction known as a spindle, which helps manage the chromosomes. A five-day-old embryo is similar dimension, however accommodates greater than 100 cells, every of which is much less weak to wreck.

“Egg freezing has been a lot more durable to crack due to the dimensions that they’re, the water content material, and that spindle,” mentioned Dr. Janis Fox, an assistant professor of reproductive endocrinology and infertility at Harvard and Brigham and Girls’s Hospital.

The expertise you need to ask for

A change in freezing expertise in recent times has made issues simpler. The earlier method, sluggish freezing, may create ice crystals, which may injury the eggs after they have been thawed, mentioned Dr. Randi Goldman, a scientific teacher of reproductive endocrinology and infertility at Harvard and Brigham and Girls’s. A number of years in the past, clinics started utilizing a course of known as vitrification, by which the temperature of the eggs within the liquid nitrogen is dropped so rapidly that they’re frozen “actually in a matter of a second,” Dr. Goldman mentioned. Eggs frozen by that technique are much less weak to wreck when thawed.

“It’s best to ask if a clinic is doing vitrification, however that’s desk stakes,” Mr. Anderson mentioned. “If somebody says they’re not doing vitrification, you need to run the opposite approach.”

Clinics which have expertise thawing eggs have typically labored with donor eggs from younger girls of their 20s. These eggs could also be extra prone to thaw with out injury, and are undoubtedly extra prone to produce wholesome pregnancies and infants.


Amin Khabani, embryology laboratory director at Pacific NW Fertility. There are 450 to 500 fertility clinics in america. Whereas greater than 20,000 American girls have had their eggs frozen, the overwhelming majority haven’t had their eggs thawed.

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Ruth Fremson/The New York Instances

Final yr, Dr. Goldman and Dr. Fox revealed a examine primarily based on a mathematical mannequin that makes an attempt to foretell a girl’s probabilities of giving beginning to a toddler from eggs that she has frozen. Their publicly accessible calculator components within the girl’s age (the older she is the decrease her probabilities) and the variety of eggs she has frozen (the extra the higher). Their examine estimates an 85 p.c profitable thaw fee for ladies who have been 36 and over after they froze their eggs, 95 p.c for ladies who have been beneath 36.

However thawing with out injury doesn’t imply a child will in the end be born. After thawing, an egg should be fertilized with sperm within the lab utilizing a course of known as intracytoplasmic sperm injection or ICSI.

“I feel sufferers could also be beneath the misimpression that we’re simply going to place the eggs again in your physique,” Dr. Fox mentioned.

Removed from it. An egg should be fertilized, grown into an embryo for about 5 days, screened for genetic abnormalities after which implanted within the womb and carried to time period. The percentages of success at every step are far beneath 100 p.c.

Dr. Fox and Dr. Goldman’s calculator, for instance, predicts 36-year-old girl who freezes 10 eggs has a 60 p.c probability of no less than one dwell beginning. A 2016 examine by researchers in Spain, which concerned 137 girls whose frozen eggs have been thawed, was much less optimistic, predicting that ladies 36 and older who freeze ten eggs have a 29.7 p.c probability of giving beginning.

What are another features of egg freezing to concentrate on?

Since youthful eggs usually tend to produce profitable pregnancies, girls would possibly assume they need to freeze their eggs of their 20s. Dr. Goldman and Dr. Fox advise towards that.

“Assuming you’ve regular fertility and nothing uncommon in your loved ones historical past, there’s undoubtedly a degree the place it’s too early, and we don’t know what the shelf life of those eggs are,” mentioned Dr. Fox, who cited a examine saying “the best age to do it was 34 however essentially the most cost-effective age to do it was 37.”

Clinics ought to be accredited by both the Joint Fee on Accreditation of Healthcare Organizations or the Faculty of American Pathologists, which inspects clinics frequently, Dr. Racowsky mentioned. She and different specialists advocate clinics be affiliated with the Society of Assisted Reproductive Know-how, the main skilled group, which audits clinics and retains success fee information.

It’s arduous to check clinics as a result of they could serve completely different affected person populations. Lots of Pacific NW Fertility’s statistics are primarily based on “youthful eggs with no fertility drawback,” Dr. Lamb mentioned. Brigham and Girls’s IVF clinic is among the few clinics that may deal with very overweight girls, a inhabitants recognized to have decrease success charges with in vitro fertilization, Dr. Racowsky mentioned.

Mr. Anderson recommends asking the clinic’s fertilization fee — “if it’s beneath 70 p.c, it’s a nonstarter,” he mentioned — and it’s “embryo conversion fee,” the share of fertilized eggs that change into embryos. “Beneath 40 p.c you need to stroll out the door; 40 to 50 p.c — that’s a keep, they’re competent.” Above 50 p.c, he mentioned, is “fairly spectacular.”

It’s also value asking what number of embryologists a clinic has, he and others mentioned. “There ought to at all times be no less than two embryologists within the lab always,” Dr. Racowsky mentioned.

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