IVF – Step by Step

Preparation for the IVF procedure

  1. To improve the efficiency of getting pregnant as early as after the second IVF attempt, it is necessary to take certain steps that seem simple at first glance, yet still require self-organization and rejection of harmful habits.
  2. Excessive alcohol consumption has a significant effect on the amount of sperm produced, as well as on their mobility. Excessive alcohol use by women in the early implantation phase and pregnancy puts the child under the influence of harmful toxins that may cause a birth defect known as fetal alcohol syndrome.
  3. Stop smoking. The chemical substances found in cigarette smoke have a harmful effect both on sperm and on egg cells. Smokers take 30% longer to conceive naturally, and certain studies have shown that female smoking lowers the possibility of pregnancy after IVF by 50% in every cycle of treatment, due to the lowered response to stimulation and a lower percent of conception.
  4. Check your weight. Excess weight or weight deficit can significantly reduce the effect of drug therapy on your organism and cause a failed response to stimulation. Measure your weight in kilograms, divided by your height (in meters) squared. This ratio is called the body mass index. If your body mass index is lower than 19 kilogram per square meter or above 30 kilogram per square meter, it is recommended that you delay IVF treatment until your weight meets these parameters. Make sure that excess weight (especially if significant) is not caused by diabetes or endocrine disorders. Consult a doctor regarding treatment. In some cases, pregnancy may be contraindicated.
  5. Maintain principles of healthy eating. Your diet should be diverse, rich in vitamins and proteins, yet with a modest amount of fats and carbohydrates. Mono-diets and other strict variations are contraindicated. Try to avoid genetically-modified products and products with large quantities of E supplements. When these substances accumulate in the organism, they can cause a decline in health, allergies, and even infertility. Drinking more than two cups of coffee per day is not recommended.
  6. Take vitamin-mineral compounds intended for pregnant women. As an alternative, you can begin taking folic acid in quantities of 400 microgram per day, three months prior to conception and three months after conception. This will lower the risk of a fetal neural tube defect occurring. You should also take potassium iodide and vitamin E in small doses about a month before the start of your IVF program. Avoid taking drugs contraindicated for pregnancy.
  7. Avoid hot tubs, saunas and bath houses.
  8. Try to lead an active lifestyle. Women are not advised to participate in intensive sport activities during the IVF treatment period. Light exercises 20 to 30 minutes in length three to four times a week are recommended for both parents, to improve their overall state of health and to help them better deal with stress associated with these medical procedures.
  9. Make sure that you are immune to rubella. Mothers lacking immunity will have to get a vaccine shot, because infection with rubella during pregnancy can lead to hearing and developmental problems in the child after his/her birth.
  10. If you have any serious chronic illnesses, don’t forget to tell your appointed specialist about your pregnancy plans, so that they may optimize your treatment or change it to suit fit these circumstances.
  11. Sexual activity. Sexual activity can remain as it is normally. However, 3-4 days prior to follicle puncture and IVF, you should abstain from sexual activity to let sufficient sperm quantity accumulate. The length of abstention should be no longer than 7 days, because sperm quality deteriorates after that time stretch. Sexual contact is discouraged after IVF and until pregnancy tests are taken. Both parents are encouraged to avoid spontaneous sexual contact, because detection of venereal diseases will demand their treatment and require further sexual contacts to take place using condoms. During the ovulation stimulation phase, pain during sexual activity is possible due to ovary enlargement.

Preliminary examination prior to IVF


Ovarian reserve test


The Ovarian reserve is a genetically provided reserve of egg cells in women’s ovaries that exists so long as pathophysiological changes in their reproductive system are absent. A reduced ovarian reserve is connected with a reduction of egg cell quantity and a decline in their quality. Reduction of the ovarian reserve happens naturally with aging, as well as after operations on the ovaries, radiation exposure, and cancer-related chemotherapy. The ovarian reserve can be tested for the follicle-stimulating hormone and inhibin B in blood serum, or it can be tested by counting the amount of antral follicles at the start of the menstrual cycle. A high level of follicle-stimulating hormone is connected with a reduced ovarian reserve.


Operations to prepare the uterus for IVF are based on indications


Pathologies of the uterus such as adhesions and polyps must be removed before the IVF procedure is initiated. Hydrosalpinx is a blocked fallopian tube filled with liquid, which lowers the probability of successful IVF due to the toxic effect the liquid in the tube has on embryos, leading many doctors to recommend removing the damaged tube before IVF procedures.


Semen analysis


Before IVF is initiated, a semen analysis (sperm sample) should be taken. If the results of the analysis show any deviations from the norm, an andrologist will have to be consulted to determine whether these deviations can be corrected and whether they are connected with other health problems.


A list of necessary tests

  • Ultrasound scan
  • Full blood count (including platelets)
  • RPR & T.Pallidum (VDRL)
  • Prolactin
  • Blood group ABO and Rh
  • Hepatitis C Ab
  • LH day2
  • Estrogen (E2) day2
  • Hepatitis B surface Ag
  • FSH day2
  • Anti-Mullerian hormone (AMH)
  • HIV 1/2 Ab + P24 Ag
  • Sperm analysis (for IP male)

A thorough examination may reveal problems that should be treated before the start of the IVF program.


IVF/ICSI. Description of the procedure’s stages. Injection drugs and video instructions


Infertility is a relatively widespread problem affecting nearly 15% of modern couples. To help childless couples, various supportive reproductive technologies are being applied in medicine. There are several existing methods for supportive reproductive technologies. The IVF method and the ICSI method are considered to be the most promising among them. Both of these methods are based on the concept that the conception process takes place outside of the mother’s body.


Steps of the artificial insemination procedure

Step one – superovulation stimulation

Hormonal stimulation begins on the third day of the menstrual cycle and lasts ten to fourteen days on average. In this time, the woman’s organism is stimulated with special drugs, so that not one egg cell fit for fertilization matures in the ovaries as usual, but several mature (typically from 10 to 20). You might be wondering why so many are needed when it only takes one for conception to occur. This quantity of egg cells is needed to improve the probability of a successful conception, because not all egg cells extracted via puncture are fertilized by sperm, and usually, only half of egg cells inseminated by healthy sperm become embryos. The more egg cells are extracted, the greater the probability of getting embryos for transplantation.

Drugs for ovary stimulation

Hormonal drugs are used to stimulate superovulation in the IVF cycle. A doctor determines the drugs’ dosage and conditions of use (known as “the stimulation protocol”) strictly individually. The dosage varies based on the woman’s age, weight, initial state of ovaries’ health (their functional reserve) and on the ovaries’ response to IVF treatment.

  • FSH drugs (follicle-stimulating hormone) – «Gonal F», «Puregon». These drugs are responsible for follicle maturation.
  • HMG drugs (human menopausal gonadotropin) – «Menopur». This drug stimulates the growth and development of follicles and the endometrium.
  • HCG drugs (human chorionic gonadotropin) – «Pregnable», «Overtly», «Horagon». These drugs activate ovulation of mature follicles and produce a mature egg cell ready for ovulation.

Follicle puncture takes place 36 hours after an injection of human chorionic gonadotropin (hCG).

Drugs for the prevention of premature ovulation

To prevent a woman’s personal hormones from interfering with superovulation stimulation and to control the superovulation process, the production of her personal hormones is blocked by agonists and antagonists.

  • GnRH agonists (dekapeptil, diferelin, buserelin, zoladex, suprefakt)
  • GnRH antagonists (orgalutran, cetrotide)
IVF: how to properly carry out injections

All women undergoing IVF procedures are forced to get shots that are subcutaneous or intramuscular, depending on the drug.


Drugs should be administered slowly.


1. Wash your hands with soap. Lather the area of injection with an alcohol swab and let it dry. Choose a new area of drug injection every time you administer it.

2. If necessary, dissolve the drug in the syringe. To accomplish this, you should fill up the syringe with a solvent, transfer it to an ampoule with dry substance and pull the mixed solution back into the syringe after the dry substance is fully dissolved. Try to keep every drop of the solution intact.

3. Replace the needle and carefully press on the piston to squeeze all the air out of the syringe. This should be done to the point when you see a drop of the solution on the end of the needle.


4а. Intramuscular administration (to the upper outer quadrant of the buttock).

Buttock Injection – Everything You Need To Know – Dr. Nabil Ebraheim – VIDEO

Try to administer the injection farther from the point where lines cross. On the right buttock, the injection should be made in the upper right corner, while in the left buttock, the injection should be made in the upper left corner. With one quick movement, fully insert the needle at a right angle to the skin’s surface. Try to keep the needle’s penetration depth stable and avoid tilting the syringe from side to side.

4b. Subcutaneous injection (belly).

How To Use the Gonal-f® RFF Pen To Self-Inject Fertility Treatments – VIDEO

Pinch a roll of skin between your thumb and your index finger. Take a syringe in your hand as you would a dart. Insert the needle into the base of the roll at a 90 degree angle in relation to its surface.


5. Extract the syringe and apply an alcohol swab to the area of injection.

Ultrasound monitoring

When superovulation is stimulated, the growth of follicles should be regularly regulated with the help of transvaginal ultrasound. Follicle growth regulation should be conducted every other day, beginning with the fifth day of stimulation. A corrected dose of drugs prescribed is also possible at this time.

With the help of ultrasound and a blood hormone test, a doctor determines when follicles are ready for puncture. Follicles usually grow 1-2 millimeters per day, and mature follicles have a diameter of 18-20 millimeters. After follicles mature, they can be punctured, and follicular fluid containing egg cells will be attained as a result.

After follicles grow to the necessary size (usually on the 10-14th day of the cycle), an hCG injection is conducted. An hCG injection helps regulate specific ovulation time, and ovulation usually occurs 36-40 hours after an injection. Ovary puncture is conducted before ovulation occurs, which is typically 34-36 hours after an hCG injection.

Step two – follicle puncture

The goal for this step is to attain egg cells from follicles of ovaries that have been stimulated by needle penetration (puncture). This procedure is conducted under the control of ultrasound, in sterile conditions, and under intravenous anesthesia. The time of a puncture procedure is scheduled beforehand by a doctor. A follicle’s contents (follicular fluid with egg cells) are transported to an embryonic laboratory. The whole follicle puncture procedure lasts 20 minutes on average. After puncture, you stay under the care and watch of the clinic’s medical personnel for 1.5 to 2 hours. After the delivery of the follicles to the lab, an embryologist conducts a “search” for egg cells, which are then moved to an incubator.

IVF – Egg Retrieval Process – VIDEO
Mature oocyte Underdeveloped oocyte

Not all oocytes attained through follicle puncture are fully mature and ready for fertilization. Approximately 5-10% of oocytes are underdeveloped, 2-5% are degenerative, with both types being unfit for fertilization.

The third step is insemination of egg cells by the sperm of the husband or donor via the IVF or ICSI method

After follicles are punctured, their follicular fluid containing egg cells is immediately transferred to an embryonic lab, where it is inspected under microscope by an embryologist who selects egg cells. Egg cells are cleansed in a special environment, after which their maturity is evaluated. Afterwards, the egg cells are placed in a special nutrient medium and carried over to an incubator, where they await insemination by sperm. Containers with egg cells, sperm, and embryos are always marked.

While a woman is undergoing the follicle puncture procedure, her husband submits a sperm sample into a special, non-toxic, and sterile container. Some men experience difficulty with producing sperm “on the spot.” They should warn their doctor of such issues in advance. Men like this can opt for preliminary cryopreservation (freezing) of their sperm, which will later be defrosted and used in the IVF cycle on the same day that the woman’s follicles are punctured. After the sperm sample is collected, the sperm are cleansed of seminal fluid with a special technology that allows selection of the most mobile and normally-functioning sperm.

A certain amount of mobile sperm are mixed with egg cells (this procedure is known as “test tube fertilization” or “in vitro insemination”) and moved to an incubator. Approximately 50 thousand sperm are used for every egg cell for regular fertilization. Penetration of an egg cell by a sperm usually takes place in several hours. Insemination is carried out 2-6 hours after follicle puncture.

Inside the incubator, constant levels of carbon dioxide, temperature and humidity are supported. At this time the environment in the incubator is hardly any different from the one typical for natural conception. The strongest sperm penetrates the egg cell and fertilizes it. Conditions in the incubator and the contents of the nutrient medium imitate those found in the fallopian tubes, creating the finest possible conditions for the embryo in vitro.

However, sometimes fertilization fails even in a controlled environment. One of the main causes of failure during IVF is lack of egg cell fertilization due to sperm pathologies, their small quantity and lack of mobility.

Icsi: IVF – Intracytoplasmic Sperm Injection

To improve the ratio of fertilized egg cells from IVF, a supplementary technology is used – the ICSI method. The difference between this method and the classic IVF procedure lies in the fact that one active and mobile sperm is selected from a sperm sample and is injected by a special needle directly into the egg cell. This way, conception is not a matter of chance dependent on random sperm, but a totally controlled process that takes place under the watch of a reproductologist in a lab, unlike the way it occurs with IVF. In this context, the doctor’s task is to inject a selected sperm into a prepared egg cell with utmost care and vigilance. The probability of success in IVF and ICSI programs increases because only the finest sperm are selected from samples and because this process has reached a level of great efficiency.

After conducting the ICSI procedure, the future development of the embryo occurs just as it would have under a standard IVF procedure.

Step four – embryo transplantation

Transplantation is conducted only with high-quality embryos. Transplantation of embryos takes place between the 2nd and 5th day of cultivation, and this is determined by the rate of their development and their quality. The first day after the date of puncture is considered to be the first day of cultivation.

Before the embryos are transplanted, the couple decides upon the number of embryos to transplant. The embryo transplantation procedure is painless, simple in form and usually very speedy (around ten minutes).

In circumstances when the couple has leftover embryos of a high quality after transplantation, the embryos are frozen for further preservation and future transplantation after defrosting, given that the pregnancy attempt is a failure or if they wish to have another child in the future.


After fertilization, implantation and adhesion of the embryo to the wall of the uterus, the long-awaited pregnancy phase begins. To make sure that the implantation was a complete success, the woman is prescribed two weeks of supportive hormone therapy. Two weeks later, a pregnancy test is taken in the form of an hCG test, which detects the presence of a hormone secreted by the embryo after it attaches to the uterus.

If the hCG test yields a positive result, parents are advised to take the first ultrasound one week after taking a pregnancy test (or three weeks after embryo transplantation). Ultrasound examination in this early stage is important, because it allows parents to terminate the pregnancy if it is ectopic (as are 2-5% of all pregnancies after IVF).

A second ultrasound examination should be conducted 10 days after the first with the aim of confirming the normal development of the pregnancy and detection of the embryo’s heartbeat. As soon as a doctor detects a heartbeat, he will advise you to visit your obstetrician-gynecologist to get signed up in the pregnancy registry. The approximate length of the pregnancy by this time will have reached 6-7 weeks.


Stages of human embryo development


In 16-18 hours after adding sperm cells to the eggs or ICSI procedure, an embryologist checks how many eggs were fertilized normally. A normally fertilized egg (zygote) represents at this moment one cell with two pronuclei. Pronuclei look like small transparent bubbles inside the cell, one of which has father’s genetic material (DNA) and the second has mother`s. When they merge, new life is formed with a unique genetic code. Eggs with abnormal fertilization (e.g., containing three pronuclei instead of two), as well as non-fertilized eggs are removed. As a rule, from 50% to 90% of the mature eggs are fertilized normally after IVF or ICSI.

In 24-36 hours after fertilization, the first division happens in zygote, and from this moment on the fertilized oocyte becomes a two-cell embryo. The cells in an embryo in the stage of division are also referred to as “blastomeres”. Embryos are assessed based on their appearance and speed of division. Good quality embryos divide fairly quickly: in two days after fertilization, normal embryos have 2-4 cells of approximately equal size with transparent cytoplasm and no cell fragmentation. Starting from the second day after IVF and up to the 6th day, embryos can be transferred into the uterus.

The most common quality grading system of dividing embryos – A-B-C-D where A is the best, D is the worst

A digit indicates the stage of blastocyst expansion.

  • 1 – early, blastocoel cavity is less than half the volume of the embryo;
  • 2 – middle, cavity more than half the volume of the embryo, but the size of blastocyst is not much greater than the size of dividing embryo;
  • 3 – expanded blastocyst – cavity is filling the greater part of the blastocyst, the shell is thinning, the size of blastocyst is at least twice as big as the size of dividing embryo;
  • 4 – blastocyst enters the natural hatching stage;
  • 5 – blastocyst is hatching out of the shell after Preimplantation Genetic Diagnosis;
  • 6 – blastocyst completely hatched out of the shell.

The first letter in abbreviation indicates inner cell mass (ICM) quality – a mass of the cell, from which the embryo will be developing.

  • А – tightly packed, sufficiently sized ICM, well-defined, no inclusions, vacuoles, strings, etc.;
  • B – ICM is well defined, but has minor defects (smaller size, loosely grouped, fewer cells, some inclusions, etc.);
  • С – ICM is either indistinguishable or has major structural damages;
  • D – degenerative ICM.

The second letter in abbreviation indicates the quality of trophectoderm (TE) – a cell layer that entirely encapsulates the blastocyst. The ultimate fate of TE cells is to become the fetal extraembryonic membranes, playing a key role in the proper implantation of the embryo.

  • А – TE is well-organized, contains many cells that form a cohesive one-layer epithelium;
  • В – TE is composed of fewer cells that form a loose multi-layer epithelium;
  • С – TE is either composed of just a few cells or has inclusions, vacuoles, strings and other deviations;
  • D – degenerative TE.

On day 3, an embryo contains, on average, from 6 to 10 cells.


On day 4, a human embryo contains, as a rule, from 10 to 16 cells, entering morula stage. Tight intercellar junctions are starting to form.

By day 5, a fluid-filled cavity, the blastocoel cavity, is formed inside the embryo. The cells of the embryo now divide into two types: those that will form the fetus and those that will become a placenta. At this stage, the embryo is referred to as blastocyst. When blastocoel cavity expands in size, the shell becomes thing from stretching and ultimately breaches while blastocyst is hatching out from the shell.

Only after this process, the blastocyst is capable of being implanted (attached) in the endometrium of the uterus. Implantation usually occurs on the 6-10 day of embryo development, including the day of fertilization.

Embryo transfer at the blastocyst stage improves the chance of pregnancy. There could be two explanations for this. First, blastocyst transfer into the uterus is more natural because in nature, it is at this stage that an embryo enters the uterus from the Fallopian tube. In addition, the cultivation up to blastocyst stage allows an embryologist to choose the “best” of embryos, because the weak embryos or embryos with genetic anomalies stop in development before they become the blastocyst.

Embryo transfer at the blastocyst stage also reduces the likelihood of potentially dangerous multiple pregnancies. High frequency of implantation of blastocysts enables to transfer fewer embryos (usually one or two) into the uterus, reducing the risk of multiple pregnancies and corresponding complications.

While blastocyst transfer is very promising for patients whose bodies produce a lot of eggs, its use for patients with poor ovarian response to stimulation and a small number of eggs is still in question. If a patient can provide just a few eggs, there is a very great risk that none will reach the blastocyst stage. They can discontinue their development and there will be nothing to transfer into the uterus. Since the conditions for artificial embryo cultivation in the lab are still far from the natural ones, despite all the advances, many embryologists believe that it is more favorable to transfer such embryos into the womb at an earlier stage than let them stay in artificial conditions. Embryos that in vitro would not have reached the blastocyst stage, can safely continue to develop in the uterus and be successfully implanted.

Days past fertilizationStage (number of blastomeres)Comments
00, only the egg
12Selecting the best embryo impossible
22-4 (sometimes 6-8)Selecting the best embryo
3-46-8 (in rare cases 8-16)Embryo becomes sphere-shaped
5more than 16Blastocyst. The last day for transfer.

Biopsy procedure at PGD

Blastocyst biopsy – VIDEO

Every couple dreaming about a child wants their baby to be born healthy. In particular, it is important for those people who have cases of inherited pathology in their family history. Until recently, the only way to avoid the birth of an unhealthy child was an abortion after discovering the genetic disorder in the scheduled examination during pregnancy. In addition to the difficulty of such procedure, there is a moral aspect that may lead a woman into a state of depression due to the loss of an unborn child. Thanks to a modern procedure of preimplantation genetic diagnostics (PGD), women can prevent the birth of a child with a genetic disease.

Indications for the use of PGD in IVF program are:

  • advanced reproductive age: over 38 in women and over 40 in men;
  • recurrent (more than two) miscarriages;
  • case(s) of chromosomal anomaly in previous pregnancy(-ies);
  • two and more failed IVF attempts;
  • one or both partners are carriers of inherited genetic pathologies;
  • when it is necessary to establish the gender – if one or both partners are carriers of gender-dependent genetic disease;
  • the necessity of birth of a “savior sibling” that requires the procedure of issue typing with the embryo.

PGD is performed by a biopsy of an embryo – by extracting one or several cells for research.

The preimplantation genetic diagnostics is only possible in a cycle of IVF/ICSI. This is due to the fact that during the standard IVF a large number of male sperm cells are added to the egg, and during the material intake not only the cells of the embryo, but parts of the sperm not involved in fertilization can get into the analysis.

For PGD analysis, a biopsy is performed on one blastomere from an embryo at the stage of division (4-10 blastomeres). While the diagnostics is done, the embryos continue to develop, and on the fifth day of the development, the “quality” embryos are transferred into the uterus or subjected to freezing for future transfer.


Cell biopsy in PGD can be performed at different stages:

  • Polar body biopsy at egg/zygote stage;
  • The biopsy at division (cleavage) stage: 6-10-cell embryo;
  • Biopsy at the blastocyst stage.

Polar body biopsy examines only the chromosomes of the mother. This method is used when the gene factor is inherited in the female line. Such analysis allows determining whether an egg is healthy, without its damage. If the egg has no defects, it is fertilized and transferred into the uterus.

The biopsy at division (cleavage) stage (3rd day of development) is studying 1-2 removed blastomeres. The follow-up analysis of embryos at the blastocyst stage is carried out if the results obtained at the stage of division are doubtful.

This diagnostics is made at the stage of embryo development when its cells have not yet taken any functions of the new organism and in the future can be safely replaced by the other cells in the process of division. Biopsy does not lead to defects in the child, and the risk of accidental damage to the embryo is less than 1%. On the bright side, only healthy embryos are transferred into the uterus and the risk of abortion due to poor genetics is no longer an issue.

The results obtained from the genetic diagnostics are checked against embryo morphology and the conclusion is made on which embryos are suitable for transfer into the uterus. Selected are the embryos with the best morphological characteristics devoid of genetic disorders.

It should be noted that, despite the high efficiency of PGD technology (95%-97%), the results of this diagnostics, in some cases, might be incorrect (both positive and negative). Therefore, couples in the “risk group” must consult with a geneticist, when in pregnancy. Some invasive procedures such as amniocentesis and chorionic villus sampling may be needed.


Freezing and Thawing of Embryos

Embryo freezing

Cryopreservation of embryos

The procedure of cryopreservation is used to freeze and store some “leftover” quality embryos from the IVF cycle. Frozen embryos are stored in special plastic straws in liquid nitrogen. There are no limits on the embryo storage period. There is evidence of successful pregnancies and childbirths using embryos stored for 10 years.


Frozen-thawed embryo transfer

If embryo transfer did not result in pregnancy, the new ET can be attempted in the next menstrual cycle, with the frozen-thawed embryos (FET). In FET cycle, the follicle growth procedure is not conducted, instead assigned are the medications preparing the lining of the uterus for the embryo transfer. Approximately in the middle of the menstrual cycle, endometrium reaches the desired characteristics (thickness and structure). Frozen-thawed embryos are then transferred into the uterus. Because embryo cryopreservation may result in condensed shell in the embryos, the assistant hatching procedure may be required.


The necessary conditions for the cryopreservation of embryos

Cryopreservation of embryos is carried out only for good quality embryos on the strictly defined stage of their development. Embryos with poor grades are not meant for freezing, since they are prone to destruction in the process. Stage of development plays an important role in the procedure of cryopreservation. Embryos can be frozen at stages of zygotes, 2, 4, and 8 cells, as well as blastocysts.

The cells of the embryo, just like other living tissues, contain water. Water forms sharp ice crystals that grow in the quick-freezing process. If you do not remove them at the very beginning, the embryo can burst. Furthermore, during freezing, some devastating salts form in the water. To avoid this problem, water is removed from the embryo and replaced with cryoprotective solution, which does not form ice. The embryos are first placed in saline phosphate buffer for some time (5-10 minutes), and then placed in a solution of highly osmotic cryoprotectant fluid. The embryo temporarily shrinks as it quickly dehydrates and then quickly extends back when the cryoprotectant replaces water. This procedure takes only a few minutes, after which the embryo is ready for freezing. The embryos are placed in glass or plastic straws for further storage. Usually, 1-4 embryos from one protocol can be stored in one straw, taking into account how many embryos are intended for thawing and FET transfer in the future. Pre-cooled straws are placed into canisters, which get sunken in the thermo-regulated isolated storage tanks (Dewars) with liquid nitrogen. Gradual freezing process takes several hours.
Once the embryos are pulled from cryobank, they must be thawed to room temperature in less than a minute or two. The complete thawing process takes about 40 minutes so that the embryos are ready for transfer or further freezing.
The embryos are pulled from rom cans and cool down to room temperature. Unlike in the freezing procedure, in the thawing process the cryoprotectant solution is gradually removed and replaced with water when embryos are placed in highly soluble environments containing more water and less cryoprotectant. Again, the embryo can burst when water is entering the cells. The process requires strict control. The embryos are ready for immediate transfer at blood temperature. Alternately, they can be placed into an incubator while awaiting transfer. Usually, before implanting, the quality of embryos is reexamined.
How well the embryos survive thawing depends on the very protocol of freeze/thawing and embryo quality before freezing. Embryos that were of higher quality before freezing, endure better. By day 3, they must have at least six cells and have no more than 20-25% of fragmentation; otherwise, they will not survive the process. Usually, some 70% of embryos are thawed successfully. After thawing, the quality of embryos is reassessed. Some of them may have part of the damaged cells. Damage may be minor or serious. Such embryos can often be restored and still have the chance to result in the birth of the child. Countless children were born thanks to this procedure.The best post-thawing quality is detected in those embryos, whose cells remained 100% intact. Most of these embryos are as viable as if they had never been frozen.
Blastocysts and embryos at the division (cleavage) stage can be transferred immediately after thawing (in 0-6 hours).
Theoretically, the embryos can remain frozen indefinitely because biologic activity is halted during cryopreservation.
The success rates of embryo transfer with cryo embryos are typically lower than with the fresh ones. This can occur not only due to damage of embryos at freezing/thawing, but also because the better quality embryos have already been transferred fresh in a given protocol.
Yes. Sometimes, when a large number of embryos are frozen at an early stage of development (2PN), all or a greater number of them will be thawed and cultivated. Just like in fresh protocol, the embryos of the best quality will be selected for transfer, while the remaining will be frozen again. Transfer of the embryos that were frozen/thawed twice can lead to a birth, but the probability of success in such protocols is reduced.

Embryo Transfer procedure. How to act after transfer.

Embryo transfer – VIDEO

Embryo transfer takes place on days 2-5 of cultivating depending on the stage of development.


On the day of embryo transfer, you need to come to the clinic 30 minutes in advance of your appointment time. The presence of the husband is possible but not necessary. On the day of transfer, you should limit fluid intake and arrive with full bladder.


After getting informed about the doctor’s readiness to conduct embryo transfer procedure, the embryologist picks up embryos in the catheter for transfer, which is a thin plastic tube with a syringe attached, and passes it to the doctor conducting the transfer.


Embryo transfer procedure is simple in technical terms. The patient lies on the gynecological chair. The doctor reveals the cervix in the mirrors, and then enters the catheter through the cervix into the uterus. The catheter contains embryos that need to be transferred into the uterine cavity. After transfer, the doctor passes the catheter to the embryologist who examines the catheter`s contents for remaining embryos under the microscope. Embryo transfer does not usually take a long time (10 minutes). The procedure is painless, although sometimes the patient may experience mild discomfort.


After the embryo transfer, you must stay in a horizontal position for 40-45 minutes, then you get dressed and invited to see the doctor to discuss further treatment and lifestyle details.


From the moment of transfer up to your first pregnancy test you can safely engage in your usual everyday activities except for heavy physical ones.

Recommendations after transfer:
  • Do not take a bath and don’t swim during the first day after transfer
  • Do not shower
  • Do not use tampons
  • Do not have sex until the first pregnancy test
  • Do not engage in jogging, aerobics, tennis, skiing and other sports
  • Do not lift weights

You can return to “work” after 24 hours of bed rest or two days of moderate activity.