Prolonged Cultivation

Prolonged cultivation – Blastocyst transfer
Blastocyst transfer is a displacement of a fertilized egg from the laboratory environment to the uterus on the 5th day of an embryonal development (instead of the 3rd day). It is one of the techniques used in choosing embryo or embryos with the highest chance of survival, implantation and thus an increase in the chances or possiblity of the woman being pregnant. To understand the difference between embryos caused by 2 days it is important to be acquainted with the early development stages of the embryos.

First week
After the sperm enters the egg, its head is enlarged in order to form a basis of fatherly pronucleus. In the next 24 hours two small rounded shapes called pronuclei could be recognized in the cytoplasm of the egg. They carry genetic information of both parents. The process of fertilization is finished after the joining and further fusion of both pronuclei.
The second day after fertilisation the embryo continues to grow and undergoes cleavage. During this process, the cell is being divided into 4, 8 and then more cells (blastomeres). After approximately 3 days the cells start to become compact forming the morula. If the embryo is transfered on the third day of its development, an embryologist can only consider the quality of the embryo according to the number of cells and the stage of cytoplasmic fragmentation.
The next two days it is possible to observe great changes in embryonal appearance during the in vitro cultivation in specially in developed media. The embryo differentiates into the embryoblast which gives rise to the foetus and trophoblast forming the placenta. The conditions for embryonal transfer are most suitable when the embryo is at the stage of blastocyst. at this particular time, the fifth day after fertilisation, the blastocyst penetrates the Fallopian tube and gets into the uterus in a natural way. Therefore because we`re trying to stimulate the natural process we carry out the transfer at the same time. The external coat of the embryo breaks down 2 -3 days after transfer and during the following 3 days it finally nests in the endometrium of the uterus.

Why the blastocysts transfer is carried out?
During observations of embryonal development at the blastocyst phase embryologists found out the most likely way to determine healthy cells with the highest chances of having a complete and successfull development. One of the major factor determining the first week of development, hatching and implantation of the embryo is the possesion of an adequate amount of energy. Obviously there is a whole rank of developmental stages it has to undergo in order to successfully attain pregnancy. However, this practice shows that the selection of embryos with the highest quality in their fifth day of development, just before their implantation into the uterus, can even increase the success rate. Ultimately, our goal is to be able to transfer only one blastocyst in each cycle to achieve such a success rate in order to keep the same probability of attaining pregnancy.
We often recommend the transfer of blastocysts to couples who have already experienced several unsuccessful IVF cycles. It depends on your decision whether the embryo transfer should be done on the 2nd, 3rd or 5th day. Our embryologist will always accept the decisions of both partners. One of the main job of the embryologist is to consider and recommend the best procedure depending on his experience and observations of the developing individual embryos. Fertilization and early development of the egg then follows the natural cycle.
The process of fertilization takes place in the Fallopian tube, the fertilized egg then migrates to the uterus where it nests in the endometrium. To imitate this natural process we use prolonged cultivation and the embryos are grown in miniincubators.
The transfer of blastocysts also means that on the 5th there are less embryos than on the 3rd day. It is because embryos whose development stop during the 4-5th days are embryos which would most likely lead to unseccessful pregnancy.

Egg donation
Egg donation is one of the possibilities of assisted reproduction where one woman-the donor donates her eggs to a couple-the recipients, to enable them to conceive. The couples who need egg donation cannot use their own eggs for different reasons.

Who could benefit?
The women whose ovaries do not produce any eggs or whose eggs can`t be used to attain healthy pregnancy can apply for egg donation. The eggs are not formed in women with the early functional failure of the ovaries or women in menopause. Women who have gone through vast surgical operations in the small pelvic region or undergone chemotherapy belong to another group of women not being able to produce eggs on their own. All these women will need donated eggs to have a child.

Retrieval of donated eggs
A woman who has decided to donate eggs has to go through an IVF cycle including hormonal injections to stimulate multiple ovulation in the ovaries, regular blood tests, ultrasound examinations and oocyte retrieval. The eggs are inseminated using sperms from a recipient`s partner. Obtained embryos are cultivated in the laboratory until the 5th day when they are transfered into the recipien`s uterus or being cryo-stored in liquid nitrogen.
The donor undergoes genetic tests as well as tests for infectious diseases. Only after negative tests results could the embryo transfer be done. 2 weeks prior to the date of transfer, the recipient is given a hormonal therapy which prepares her body, particulary the uterinal endometrium for pregnancy. Then one or two embryos are transfered into the uterus at the right time.

Donors could be divided into 3 groups:

* voluntary oocytes donors
* donors got by recipients
* donors rgistrated in an IVF programm, during the oocyte retrieval more and higher quality eggs are obtained than the donor wishes for her own pregnancy

Oocyte recipient
Oocyte recipients are registered in a database of recipients in an embryologic laboratory according to the recommendation of a doctor from the Sanatorium Helios SK. After the registering a woman and putting her on a waiting list, the sperms of a partner have to be examined, frozen and stored in liquid nitrogen until the day of eggs retrieval.

Donation of embryos
In some pairs, the donation of embryo is indicated. A donated embryo could come from a pair who have already successfully undergone embryotransfer, have spair frozen embryos and have decided to donate them. Both partners are then tested like the oocyte donor.
Another case is when a woman has decided after a hyperstimulative eggs retrieval process to donate at least 5 eggs. The eggs are consequently fertilized with sperms from a donor, chosen by an andrologist from a spermbank in our centre. Developed embryos are cultivated until the 5th day and the highest quality blastocysts are frozen and stored in liquid nitrogen.

How many embryos will be transfered ?
Every single embryo is individualy frozen and therefore it can also be individualy defrosted in our centre. However, not every embryo after beeing defrosted shows the same survival potential.There are approximately 10 % non-vital embryos. Approximately 10 % of defrosted embryos will not survive. It is usually recommended to transfer 2 embryos but our priority is the patients` wish.

Transfer efficiency and cryoembryotransfer using of donated eggs and embryos Generally, the success rate after cryotransfer is lower than after transfer in a cycle without freezing. In older patients and in patients with immature eggs cryotransfer is often the only possibility of attaining a longed-for pregnancy.

Why freeze sperms
It is possible to freeze sperms in cases where the partner is not available at the time of insemination or artificial fertilization. It could also be applied to men who will eventually travel abroad for a long time e.g. military services or before chemotherapy. It is possible to keep the sperms for a long period and to defreeze them at the right time to be used for subsequent fertilization.

Why freeze embryos
It often happens that after ovarian stimulation and oocyte retrieval we obtain more than one or two oocytes, eventually more embryos than necessary for transfer (1 or 2) in one IVF cycle. So, if there are some healthy embryos of high quality left over it would be a great waste to let them die. By freezing your embryos you get the chance to carry out multiple attempts at pregnancy with simply only one stimulation cycle. By using this procedure the hormonal intervention recieved by your organism as well as the number of cycles through which your ovaries are stimulated are considerably lowered.

How embryos are being frozen
After insemination the oocyte is cultivated in a laboratory for about 3-5 days in a nourishing medium before it is transfered back to the uterus. As long as the other embryos are in good condition they are suitable for freezing.
Generally, during the method of conventional freezing of biological tissues the ice crystals formed cause ireversible damages to the cell structures. However, some animals are able to survive even in temperatures below freezing point thanks to special antifreezing substances, their bodies contain. These substances include glycerol and glucose which prevent formation of crystals at temperatures below zero. Therefore similar substances called cryoprotectors are used in the laboratories.
Initially, the embryo is deprived of all the water it contains and it is substituted for a cryoprotective mixture. Then it is frozen to a temperature of about -196 ºC, which is the temperature of liquid nitrogen. The embryo can stay in such conditions for an unlimited period of time and can be transfered after several months or even years after the time of freezing.

What is a cryocycle?
It is a cycle during which a defrosted embryo is transfered into the uterus. It is not necessary to stimulate multiple ovulation and no daily doses of hormonal injections or regular check ups are necessary during this proces. You need to inform your doctor about the beginning of your cycle, the first day of your menstruation before the start of the cryocycle during which the frozen embryos should be transfered.
The doctor will prescribe the hormonal tablets which you need to take 2 weeks prior to the planned transfer. An ultrasound examination is applied on the 14th day of your menstrual cycle. The best day for transfer is planned according to the result of this examination. The procedure is the same as during the conventional stimulation cycle. The hormonal tablets are still taken even after the transfer. In case of positive pregnancy test taking of these tablets continues until the 12th week of pregnancy.

What is the success rate when using frozen embryos?
The success rate of implanted frozen embryos is a bit lower than the rate of implanted non - frozen embryos. The main reason for this is that the highest quality embryos are chosen by the embryologist for the conventional transfer an the rest of the embryos are frozen. It can also happen that the defrosted embryo is no longer suitable for the transfer. However, it is true that embryos of similar quality should have the same chances for successful implantation whether they were frozen or not.

Subsequent care after ET
You should continue taking the tablets according to the prescription of a doctor after the transfer. After the transfer it is a matter of waiting whether the embryo will successfully be implanted and starts its development or not. The pregnancy blood test should be done approximately 12 days after the transfer. The centrum of assisted reproduction Sanatorium Helios SK is a contract partner of all registered health-insurance companies. IVF therapy is partialy financed by your health-insurance company in indicated cases.The drugs used to stimulate maturation of eggs are partially paid for by the patients too.

Nowadays according to the law 777/2004 IVF treatment expenses are reimbursed by a health insurance company in the cases indicated below:

* absent or damaged Fallopian tubes
* endometriosis
* absent or damaged ovaries
* sterility with a non-recognisable cause
* low quality sperms of a partner
* immune conditional sterility
* inherited diseases and others

There are 3 cycles of assisted reproduction reimbursed.
Some of the procedures of assisted reproduction are not covered by a health insurance company so patients cover all the costs by themselves. The final prices will be accurately calculated and provided to you at Sanatorium Helios SK. You will be informed about the expenses covered by your health insurance company and how much you will have to cover by yourselves prior to the start of your stimulation in any case.

Sanatorium Helios SK is a contract partner of these health-insurance companies in Slovakia.