So­cial Free­zing: pro­ce­dure & chances of suc­cess

So­cial free­zing, also known as cryo­p­re­ser­va­tion in me­dical ter­mi­no­logy, re­fers to the pre­cau­tio­nary pro­cess of har­ve­s­ting and then free­zing un­fer­ti­lized eggs wi­t­hout me­dical ne­ces­sity. With this me­thod, women can pre­vent their age-re­lated loss of fer­ti­lity and fulfil their de­sire to have children at a later date by “tha­wing” the eggs again.

Usually, the pro­cess of so­cial free­zing be­gins with the first con­sul­ta­tion at a fer­ti­lity clinic. Preli­mi­nary me­dical ex­ami­na­tions then take place on site. After hor­monal sti­mu­la­tion, se­veral eggs are re­moved du­ring the cryo­p­re­ser­va­tion then shock-frozen (vi­tri­fi­ca­tion) and stored in the la­bo­ra­tory for a very long time.

Step 1: Preli­mi­nary ex­ami­na­tion

After a de­tailed preli­mi­nary dis­cus­sion with ex­perts, with re­pro­duc­tive phy­si­cians or fer­ti­lity doc­tors, the next step is a preli­mi­nary me­dical ex­ami­na­tion using blood va­lues (hor­mone ba­lance) and ul­tra­sound. The doctor will check whe­ther the ne­ces­sary re­qui­re­ments for so­cial free­zing are ful­filled (pro­ba­bi­lity of suc­cess / chances) and in­form you about pos­sible risks of the tre­at­ment. Other un­cer­tain­ties can be cla­ri­fied in ad­vance by a spe­cia­list.

Step 2: Pre­pa­ring for hor­monal sti­mu­la­tion

If you meet all the re­qui­re­ments after the preli­mi­nary ex­ami­na­tions, a date will be set for the start of the sti­mu­la­tion. The plan for both the du­ra­tion and do­sage du­ring the hor­monal sti­mu­la­tion of the ova­ries is drawn up in ad­vance tog­e­ther with the doctor. As the cor­re­spon­ding me­di­ca­tion is only available on pre­scrip­tion, you will re­ceive a doc­tor’s pre­scrip­tion with pro­fes­sional in­s­truc­tions. Sche­dule en­ough time to re­ceive the me­di­ca­tion (usually in­jec­tions) to be able to start on time.

Step 3: Hor­monal sti­mu­la­tion

Du­ring a cer­tain pe­riod of time, which often lasts bet­ween 10–14 days, you in­ject the pre­scribed hor­mone pre­pa­ra­tion at home. The hor­monal sti­mu­la­tion should lead to as many eggs as pos­sible ma­tu­ring by the time of re­trieval. In order to mo­nitor the growth of the fol­licles and keep an eye on the hor­mone le­vels, re­gular check-ups are car­ried out via ul­tra­sound and blood sam­pling. This also helps to de­ter­mine whe­ther the do­sage should be ch­anged and iden­tify the per­fect time to re­trieve the ma­tured eggs. After this de­ter­mi­na­tion, a hor­mone is in­jected once (“trigger shot”) to trigger ovu­la­tion. Once ovu­la­tion has been suc­cessfully trig­gered, the doctor can begin the coll­ec­tion pro­ce­dure.

Step 4: Re­trieval of the eggs

In order to re­trieve the ma­tured eggs, you will have to go to your ac­com­panying fer­ti­lity clinic (usually one day) after the last in­jec­tion. You will be ex­amined again and in­formed about the next steps. After a me­dical con­sul­ta­tion, you will then be taken to an ope­ra­ting theatre where the re­trieval will be car­ried out under a short an­es­thesia. The pro­ce­dure is usually minor and only takes about 15–30 mi­nutes. Du­ring this time, the doctor re­moves the fol­licles from the ova­ries by so-called “va­ginal fol­licle punc­ture”. Fol­licles, which con­tain a ma­ture egg, are “su­cked out” th­rough a very thin needle. Fol­lo­wing this short pro­cess, you will be taken to a quiet room to wake up and rest until you are ready to go home. For your own safety, you will need to be pi­cked-up by a person of your choice due to the (al­beit short) ge­neral an­es­thesia.

Step 5: Free­zing (vi­tri­fi­ca­tion) of the eggs

After the fol­licles have been coll­ected, a spe­cia­list bio­lo­gist will ex­amine how many of them con­tain a ma­ture egg. Sui­table oo­cytes are then frozen wi­thin a few se­conds at ‑196°C (“shock free­zing”). Me­di­cally, this pro­ce­dure is also called “vi­tri­fi­ca­tion”. This me­thod of­fers many ad­van­tages, as on the one hand it does not da­mage the cells and on the other hand has a very high, al­most risk-free “res­to­ra­tion rate” (98%).

Step 6: Sto­ring the eggs

The good thing is that you can safely store your vi­tri­fied eggs for se­veral years, even de­cades. The greater the number of eggs stored, the greater the chance of pregnancy at a later date and thus of ful­fil­ling your per­sonal wish to have a child.
When the time is right for you, the eggs are thawed again and can then be fer­ti­lized.

Chances of suc­cess

Both the quan­tity (“egg re­serve”) and the qua­lity of the eggs do not de­velop li­ne­arly with age. To better un­der­stand the chances of suc­cess with so­cial free­zing, it is worth re­cal­ling the pro­ce­dure: After hor­monal sti­mu­la­tion of the ova­ries, the eggs are re­moved and then frozen at minus 196 de­grees Cel­sius. Ac­cor­dingly, there are two main steps in this pro­cess that de­ter­mine the sub­se­quent li­keli­hood of suc­cess of a pregnancy from cryo­p­re­served eggs: 1. the re­trieval and 2. the free­zing of the eggs.

Age

One of the most im­portant sta­tis­tical fac­tors for suc­cess is the age of the pa­tient at the time of egg coll­ec­tion. This is be­cause the qua­lity of the eggs de­creases with in­cre­asing age — in me­dical terms, this is re­ferred to as the “eu­ploidy of the cell or­ga­nisms” de­cre­asing.

In ad­di­tion, the na­tural egg re­serve de­creases with in­cre­asing age, which is why more cy­cles are needed to ob­tain the same number of eggs. A cri­tical age re­gar­ding the oo­cyte re­serve is often seen at around the age of 35, since from this point on­wards the rate of na­tural births de­creases dis­pro­por­tio­na­tely. In ge­neral, it is re­com­mended to re­trieve at least 10–20 eggs for so­cial free­zing. Ac­cor­ding to a 2017 study of 520 ICSI cy­cles, women aged 34, 37 and 42 have a 90%, 75% and 37% chance of at least one suc­cessful birth with 20 frozen eggs, re­spec­tively. A 20-year-old woman even has a 94% chance with 20 frozen eggs.

De­sired number of births

Si­mi­larly, one can con­sider the case where pa­ti­ents de­sire mul­tiple births based on the frozen eggs. Again as­suming 20 frozen eggs are stored, a 34-year-old woman has a 66% chance of ha­ving at least 2 births. For a 42-year-old woman, on the other hand, the chance is only 7%.

If at least three live births are to be achieved, the pro­ba­bi­lity of a 34-year-old woman de­creases to 38%; the pro­ba­bi­lity of a 42-year-old is about 1%.

The­r­e­fore, a clear cor­re­la­tion can be de­mons­trated bet­ween the age at the time of egg re­trieval and the pro­ba­bi­lity of suc­cess of a sub­se­quent pregnancy from so­cial free­zing. It should be noted, that these are sta­tis­tical va­lues which in prac­tice vary from person to person. Si­mi­larly, re­gard­less of age, there is no gua­rantee of suc­cess with so­cial free­zing for a sub­se­quent pregnancy.

Me­thod

There are also fur­ther dif­fe­rences in suc­cess rates due to the me­thod of free­zing the eggs. A di­stinc­tion is made here bet­ween so-called “slow free­zing” and vi­tri­fi­ca­tion. The two me­thods differ pri­ma­rily in the speed with which the eggs are frozen.

In slow free­zing, the re­trieved oo­cytes are cooled by about 2 — 3 de­grees Cel­sius per mi­nute over a longer pe­riod of time until they reach the re­quired minus 196 de­grees Cel­sius. This low final tem­pe­ra­ture is ne­ces­sary to stop the bio­lo­gical pro­cesses in the oo­cytes and make long sto­rage pos­sible wi­t­hout loss of qua­lity.

In vi­tri­fi­ca­tion (also called “flash free­zing”), the eggs are im­mersed in li­quid ni­trogen, which al­lows them to be frozen at minus 196 de­grees Cel­sius wi­thin mi­nutes. For egg free­zing, speed is a cru­cial suc­cess factor: eggs lar­gely con­sist of water, which is why it is im­portant to pre­vent crystal­li­sa­tion of the li­quid du­ring free­zing. Ac­cor­dingly, vi­tri­fi­ca­tion is cle­arly the more pro­mi­sing me­thod, which is why it has be­come wi­dely ac­cepted in re­cent years [2].

Sum­mary

In sum­mary, the age of the woman, which is ide­ally below 35 years, in com­bi­na­tion with the me­thod of free­zing (vi­tri­fi­ca­tion) are de­cisive fac­tors for in­cre­asing the pro­ba­bi­lity of suc­cess of a sub­se­quent pregnancy th­rough so­cial free­zing.

You can de­cide for yourself if and when you want to thaw the eggs for use. If you cannot get pregnant na­tu­rally, as­sisted re­pro­duc­tion (IVF or ICSI) is pos­sible. This in­volves fer­ti­li­zing the eggs with the man’s sperm cells. Once cell di­vi­sion has begun, the fer­ti­lized egg can be in­serted into the uterus. De­spite the high pro­ba­bi­lity of suc­cess of achie­ving a pregnancy with the help of so­cial free­zing even at a late age, there is no gua­rantee of an un­com­pli­cated fa­mily for­ma­tion. Com­pli­ca­tions can occur for a va­riety of re­asons, which is why spe­cia­list care is al­ways re­com­mended.

So­cial Free­zing is as­so­ciated with few risks and is ra­ther harm­less. Apart from the in­creased li­keli­hood of a mul­tiple pregnancy with as­sisted re­pro­duc­tion, there are still pos­sible com­pli­ca­tions that pregnancy at an older age can bring: in­creased sus­cep­ti­bi­lity to ge­sta­tional dia­betes or high blood pres­sure.

At the same time, some risks are eli­mi­nated or greatly mi­ni­mised in a pregnancy re­sul­ting from so­cial free­zing if the eggs were cryo­p­re­served at the youn­gest pos­sible age: ge­netic mal­for­ma­tions or high risk of mis­car­riage due to age.

When Ame­rican com­pa­nies like Face­book and Google an­nounced in May 2014 that they would pay for the so­cial free­zing tre­at­ments of their fe­male em­ployees, it made big waves in Ger­many. It was the be­gin­ning of a so­cial de­bate: To what extent should young women be en­cou­raged to put their careers be­fore fa­mily plan­ning, and to what extent is it per­mis­sible to help them do so me­di­cally?

Alt­hough there was a lot of media at­ten­tion around the topic, most of the ar­ticles missed the real truth with their cen­tral thesis — so­cial free­zing is mainly so­me­thing for career-ori­ented women. In a 2013 study, women were asked why they had their eggs frozen (mul­tiple ans­wers were pos­sible). Con­trary to the common as­sump­tion that so­cial free­zing is pri­ma­rily done for career mo­tives, only 24% of the re­spond­ents gave this as a re­ason. A si­gni­fi­cantly larger pro­por­tion of re­spond­ents, na­mely 88%, stated that they curr­ently did not have a sui­table partner for ha­ving children. 15% gave fi­nan­cial re­asons or named a too high burden as a re­ason for post­po­ning the child wish [3].

An­o­ther mo­ti­va­tion for so­cial free­zing that is often ne­gle­cted: In cer­tain cases, cancer pa­ti­ents have their eggs frozen be­fore che­mo­the­rapy in order to have them fer­ti­lized in case they want to have children later. This va­riant is also called me­dical free­zing.

At Fer­tilly, we have made it our mis­sion to ac­com­pany cou­ples (ho­mo­se­xual and he­te­ro­se­xual) and sin­gles on the way to ful­fil­ling their child wish. In doing so, it is im­portant to us to create trans­pa­rency in the area of fer­ti­lity ser­vices, to pro­vide in­for­ma­tion and know­ledge on the to­pics of pregnancy and fer­ti­lity and to help you to find the most sui­table Fer­ti­lity Center. Th­rough co­ope­ra­tion with first-class Fer­ti­lity Cen­tres and cli­nics in Eu­rope, en­qui­ries about Fer­tilly are given pre­fe­ren­tial tre­at­ment. This means that our pa­ti­ents avoid the usually long wai­ting times and get ap­point­ments more quickly.

If you would like more in­for­ma­tion about Fer­ti­lity Cen­ters, suc­cess rates and prices, please contact us using this ques­ti­on­n­aire. We will ad­vise you free of charge and wi­t­hout any ob­li­ga­tion.