In vitro fertilization is a complex multi-stage procedure, the final stage of which is the implantation of embryos into the uterus. Next comes the time for implantation, that is, the attachment of an egg fertilized in the laboratory to the endometrium prepared with drugs. The importance of this process and its features during IVF will be discussed in this article.

Timing of embryo implantation after IVF

During conception under natural conditions, the egg fertilized in the fallopian tube descends into the uterine cavity, where it attaches. From the moment of conception to the attachment of the embryo, it takes from a week to 10 days. The implementation process itself takes 40 hours.

Sometimes the above dates may shift, in which case they speak of early and late implantation.

Implantation is called early when the embryo is introduced into the uterus 6-7 days after ovulation. This is rare, since at this time the endometrium is not yet sufficiently prepared for implantation.

Late implantation occurs on the 10th day after fertilization. The implantation process takes up to 3 days.

After IVF, as a rule, occurs. This type of implantation is favorable for fertilization in artificially created conditions.

Embryo implantation after IVF: signs, symptoms and sensations

After the embryo transfer, the woman anxiously waits for the first signs that everything went well and the embryo has successfully implanted into the uterine cavity. Indeed, this stage is extremely important, because the outcome of the pregnancy largely depends on it.

The main subjective criteria for the implantation that has occurred are:

• small beige or pink discharge. The fact is that the embryo, during the process of implantation, destroys the endometrium, which contains a large number of blood vessels. If implantation is active, discharge may appear;
• minor aching or nagging pain in the lower abdomen similar to menstrual pain;
• feeling of nausea or change in taste. Most often - a metallic taste in the mouth;
• the appearance of low-grade fever, which ranges from 37.0 - 37.2 0 C and rarely rises above;
• general symptoms in the form of weakness, dizziness, feelings of irritability, increased excitability.

In case of any deviations from the norm in the presence of bloody discharge from the genital tract or pain in the lower abdomen after IVF, it is necessary to consult with your doctor to exclude the development of pathology or a threatening spontaneous miscarriage.

Pregnancy is considered clinically confirmed:

• when increasing, the study is carried out after 14 days;
• at high basal temperatures. Read more about ;
• according to the results of ultrasound, which is performed on the 5th day after embryo transfer, and then 10 days later for dynamic monitoring of fetal development.

Why embryo implantation does not occur after IVF

In order to understand the reasons why implantation may not have occurred, it is necessary to understand what conditions must be met for the successful attachment of the embryo. So, successful implantation occurs when:

• endometrial thickness not more than 13 mm;
• serum progesterone is within normal limits;
• there is a sufficient amount of nutrients in the endometrium.

Lack of implantation during IVF may be caused by:

• genetic defects on the part of the embryo;
• pathological condition of the endometrium;
• congenital malformations of the embryo;
• the presence of a thick shiny membrane of the egg, which prevents its attachment in the uterine cavity.

Even if there is no positive result, you should not despair, because one failure is not a death sentence. Each case requires a thorough medical analysis, after which the IVF procedure can be repeated.

Is it possible to improve embryo implantation during IVF?

The question of whether a woman can, through her actions, help the embryo implant into the uterine cavity is of interest to many expectant mothers. Of course, the very process of establishing the embryo in the uterus is physiological, but certain behavior of a woman can both contribute to its successful completion and provoke complications. Here are simple rules to help reduce the risk of failure:

• limiting physical activity;
• sexual rest;
• proper and nutritious nutrition;
• absence of stressful situations;
• no hypothermia;
• exclusion of medications unless they were prescribed by a doctor;
• absence of thermal effects on the body, such as baths, saunas, baths;
• compliance with the work and rest regime.

These rules are valid for the entire period of growth and development of the baby in the womb, but special care should be taken in the first 10-12 days after replantation. During this time, you should lie down more and, if possible, avoid any work, including cooking, cleaning, washing, ironing, etc. Time on a laptop and tablet should be kept to a minimum. Remember that after the transplant, the woman is no longer alone, and, among other things, it depends on her actions whether the embryo can grow into a healthy, full-fledged baby and receive that portion of affection and love that the parents are ready to give it.

Why don’t embryos take root in the uterus after transfer to IVF?

The key question after unsuccessful IVF is: “ Why does the embryo not take root after transfer? in the uterus? How can you influence? Let's consider these questions in detail.

What can prevent the embryo from attaching?

Why does the embryo not take root in a uterus with impaired decidualization?

The endometrium is transformed into high-quality decidual tissue in the second half of the cycle at. It is proportionally represented by immune cells (NK cells and Tx).

The mucous membrane is an intelligent “detector”. Until recently, it was believed that a genetically “wrong” embryo is not capable of long-term survival. In fact, such an embryo is capable of producing many biologically active substances. He thus tries to “please” the endometrium.

A fully decidualized endometrium, a hormone-dependent tissue, “recognizes” the genetically altered embryo and stops synthesizing a number of nutrients for it. As a result, the embryo stops developing. Nature saves a woman from disappointment and termination of pregnancy.

There are two options for impaired mucosal decidualization:

• (insufficient number of NK cells);
• increased local activity (lack of local immunoregulation and excessive mobilization of NK cells).

As a result of disorders, the endometrium reacts equally to a full-fledged and genetically modified embryo. The attachment of a defective embryo in this case leads to That is, after IVF, the embryo does not take root, although it lingers in the uterus for some time.

What can be done to ensure that the embryo takes root?

The treatment performed (in order to increase the chances of attachment) is selected taking into account the morphological changes in the decidual tissue.

To improve the quality of the endometrium in case of deficiency of immune activity, it is recommended:

• local irritation of the mucous membrane using pipell biopsy (collection of endometrial cells with a disposable tube with a side hole and a piston inside) or;
• moderate ovarian stimulation;
• support of the luteal phase with low doses of human chorionic gonadotropin;
• introduction of seminal fluid;
• intrauterine injection of peripheral mononuclear cells cultured with human chorionic gonadotropin.

With increased immune activity, a condition precedes inflammation occurs, and embryos do not engraft after IVF transfer.

• avoid local irritation of the uterine mucosa;
• carry out standard ovarian stimulation;
• sufficient support for the luteal phase;
• use corticosteroids, intralipids, intravenous immunoglobulins;
• sexual rest after embryo transfer;
• intrauterine injection of follicular fluid.

Effect of stimulation on implantation

A significant reason why embryos do not implant after IVF is controlled ovarian stimulation (COS). But it should immediately be noted that the exact cause and mechanism of changes in the uterus that occur under the influence of CBS have been little studied. There is no possibility to histologically examine the endometrium on the eve of transfer, since if the integrity of the mucous membrane is damaged, embryo transfer cannot be performed (it will be ineffective). That is, obtaining material to study the issue is problematic.

Studies show that in stimulated cycles, a premature release of progesterone can be observed (even before follicle puncture), which negatively affects the implantation properties of the endometrium.

The level of preimplantation losses after stimulation of ovulation, compared with natural pregnancy, is significantly higher - this confirms the unfavorable effect of CBS on implantation.

Which embryos take root better: fresh or “cryo”

Analysis of fresh and “cryo” cycles (transfer is carried out in a natural cycle) showed a pattern that the pregnancy rate in cryoprotocols is higher than in fresh protocols. And the frequency of miscarriages in fresh protocols is higher than in “cryocycles”.

Cryo embryos take root better in the uterus. In addition, Italian scientists have confirmed that the frequency of clinical and progressive pregnancies in “cryo” cycles is higher, and the frequency of miscarriages is lower.

Therefore, it was concluded that freezing embryos and transferring them in a natural cycle (without stimulation) is a fairly effective technique and allows one to overcome unfavorable endometrial transformations that occur during stimulation.

Implantation window offset

During one menstrual cycle, a woman has several days when the blastocyst is able to take root in the uterine cavity. This period is called the implantation window. The search for methods for determining the implantation window is still ongoing. A method for determining the expression of more than 200 genes in the endometrium has become widespread. By studying these genes, scientists can determine the period during which an embryo can take root in the uterus.

In women with repeated unsuccessful attempts at in vitro fertilization, a shift in the implantation window (earlier or later than expected) was detected in 25% of cases. Taking into account and using this information in practice, in 50% of cases the fact of pregnancy in women with repeated unsuccessful cycles is obtained.

Diseases that prevent embryos from implanting after IVF

There are a number of pathologies and conditions that can interfere:

• (level increases);
• . Excess weight negatively affects egg maturation and implantation.
• Age. It has long been believed that age does not have the best effect on oocyte quality. But it turns out that age may prevent the implantation of embryos obtained from donor eggs. Studies have shown that after 45 years, the implantation properties of the inner lining of the uterus significantly decrease.
• Immunological disorders.

The influence of morphological changes in the structure of the endometrium

Implantation is negatively affected by: thin endometrium. The new technique gives more positive results regarding endometrial growth compared to standard treatment methods.

If the embryo does not take root, what happens to it next? The fertilized egg stops developing and leaves the uterine cavity along with menstrual flow.

This also happens in natural conditions, more often than women suspect. In a natural cycle, the chance of conceiving is 30%. A significant number of embryos conceived in conditions of absolute health are genetically defective.

“Healthy” endometrium prevents them from attaching in 30% of cases at the pre-implantation stage. In 30% of cases, a defective embryo is attached, but within a few days the endometrium (at the post-implantation stage) stops its development. In 10% of cases, implanted embryos in the uterus lead to spontaneous miscarriages, a sign of which is bloody discharge.

The process of in vitro fertilization is quite labor-intensive, both for future parents and doctors. The protocol begins with preparation and medical examination, while patients must follow all the specialist’s recommendations.

The actions of doctors also play an important role in the IVF process. If something goes wrong, the procedure will most likely end in failure. If implantation does not occur during embryo transfer, the protocol is considered unsuccessful. In this case, it is necessary to identify the cause and get rid of it in order to increase the chances of repeated IVF.

Why implantation does not occur during IVF, and how to detect a violation, worries many expectant mothers. As soon as the embryos are transferred, the woman begins to think about whether the long-awaited pregnancy will occur or not. You can find out the answer to this question 10-14 days after cell replantation using an hCG test or a pregnancy test.

If IVF does not take root, the signs will be as follows. The main sign of lack of implantation is a very low level of hCG. This hormone begins to be secreted by the fetus as soon as it attaches to the wall of the uterus. Accordingly, if implantation has not occurred, hCG will not begin to be produced, and a blood test will show this.

The level of hCG in a woman’s body can also be determined by a pregnancy test for home use. It is a kind of indicator that is colored if the hormone is present in the urine. But it is worth noting that in the early stages, tests may show a negative result, this is due to their low sensitivity.

Another sign of lack of implantation is heavy bleeding or menstruation. If a woman gets her period, we can conclude that the fetus has not implanted and pregnancy has not occurred.

Many patients are concerned about the question, what symptoms may appear during fetal implantation? As a rule, this process is not accompanied by any symptoms. Pain in the chest and lower abdomen, nausea and drowsiness are the consequences of taking hormonal drugs in preparation for IVF.

But some women may experience implantation bleeding due to damage to small capillaries during the process of embryo attachment. Such discharge is scanty and light, and it appears 5-7 days after replanting. If the blood is dark and profuse, then there is a threat of miscarriage.

Causes

Why the embryo does not take root after transfer is a question that worries approximately 50% of all women who have undergone IVF. It is with this probability that pregnancy may not occur.

As a rule, the woman has already undergone examination and cured all pathologies that may affect implantation. The procedure was completed according to all the rules, but ended in failure. Let's look at the main reasons why fetal implantation does not occur after IVF:

• poor endometrium;
• inflammation of the fallopian tubes and adhesions;
• hormonal problems;
• low-quality embryos;
• patient age over 40 years;
• genetic disorders;
• incompatibility of partners;
• bleeding disorders;
• obesity in women;
• medical error or incorrect fulfillment of doctor’s instructions during the preparation process.

The condition of a woman’s reproductive organs plays a very important role in the process of pregnancy. If the patient has been diagnosed with endometriosis, hydrosalpinx, or polyps in the uterus, then the likelihood of successful IVF is significantly reduced. Problems with the uterus prevent the fetus from attaching, and hydrosalpinx (adhesions with the formation of fluid in the tubes) has a toxic effect on the embryo and prevents it from developing.

If the reason for the lack of implantation during IVF is poor endometrium, then special attention is paid to eliminating this problem, otherwise the attempt will again be unsuccessful. In case of hydrosalpinx, it is recommended to remove the fallopian tubes before IVF if conservative treatment in the previous protocol did not bring results.

If there is no implantation after IVF, the doctor may suspect incompatibility between the partners. In this case, the mother’s body perceives the embryo as an enemy and destroys it. To identify the disorder, a special HLA typing test is prescribed. Also, the cause of miscarriage may be a chromosomal abnormality of the embryo, for the detection of which PGD (preimplantation genetic diagnosis) is prescribed.

In the event that a mother is found to have disturbances in the hematopoietic system, she is prescribed treatment. Too thick blood disrupts placental blood flow and leads to fetal death. Therefore, during repeated IVF, blood-thinning drugs will be prescribed as prophylaxis.

The reason for the lack of implantation during IVF can be endocrine disorders, often a lack of progesterone. In this case, the woman undergoes additional examination by an endocrinologist and, if necessary, treatment. If there is a lack of progesterone, drugs will be prescribed to support pregnancy, for example, Utrozhestan or Duphaston.

Often the reason for the lack of implantation is bad embryos. They are not viable enough and therefore do not take root in the uterus. This can occur due to poor quality of eggs and sperm, as well as due to improper actions of the embryologist.

To improve the quality of the embryos, treatment may be prescribed to both the man and woman. Additional ART methods are also used, for example, PIXI, which make it possible to study the quality of cells and select the most viable ones for fertilization. It is also very important to choose the most favorable day of the cycle for replanting.

Future parents should remember that the older they are, the worse the quality of the reproductive cells. Accordingly, the likelihood of unsuccessful implantation after IVF greatly increases. Therefore, if a man and woman want to undergo IVF, it is better to do this before the age of 35.

Treatment

Many patients wonder what to do after unsuccessful IVF? The first thing you need to do is stop being upset; there is no need for depression here. Then it is recommended to consult a doctor and consult; a specialist should assess the situation and voice possible reasons for the failure.

During the period of preparation for the next protocol, a woman should lead a moderately active lifestyle, play sports, such as yoga, and eat right. If you are overweight, you must definitely fight it, since obesity negatively affects the implantation process.

It is worth noting that lack of weight also has a bad effect on a woman’s reproductive function. If a patient wants to become pregnant using IVF and carry a healthy baby, she must bring her weight back to normal.

Reasons for failure in IVF (Video)

The implantation window during IVF is a concept purely for reproductive specialists, who use it to determine the time during which the uterus can interact with the embryo or embryos. With IVF, this period falls on the 20th or 21st day, depending on the drugs used to stimulate and the body’s sensitivity to them. One should take into account the fact that implantation during IVF is possible when a five-day-old embryo at the blastocyst stage enters the uterus during an open implantation window. Before transferring the embryo, one should take into account the fact whether there is a membrane around it that interferes with implantation, and if there is one, then hatching should be carried out - the artificial removal of the zona pellucida of the blastocyst, which prevents implantation.

When does implantation occur after IVF?

So, implantation during IVF is the process of implantation of a fertilized egg under artificial conditions into the endometrium of the uterus, characterized by the ingrowth of embryonic villi into the endometrium, through which their nutrition and growth will occur, ensuring further development and formation of the fetus.

Eco treatment for hepatitis B - how it happens

When does implantation occur after IVF? To understand this process, you need to understand when implantation occurs, what determines the time of its occurrence. So, on average, ovulation occurs on the 14th day from the start of menstruation, after which the egg enters the fallopian tube and within 24 hours it is fertilized by sperm, and only by the end of the third or fifth day the embryo enters the uterine cavity and the implantation process begins, which by the 7th day the day ends. With IVF, all processes occur outside the woman’s body and only the implantation process occurs in her body.

Embryo implantation after IVF

Embryo implantation during IVF is carried out when the embryos are ready and ripe for transfer. In this case, one should take into account the duration of the implantation window, when the probability of implantation is favorable depending on the woman’s hormonal background. After embryo transfer, implantation occurs within the first hours or within two days, on average it takes up to 40 hours.

Implantation: IVF is possible only when the thickness of the endometrium is between 7 and 13 mm, which directly indicates the outcome of pregnancy and the chances of favorable implantation.

All women who undergo in vitro fertilization are interested in the question: when is the embryo attached to the uterus after IVF? But what day is the embryo implanted? Since during the IVF procedure, mature embryos are transferred to the endometrium, which are already ready for implantation and therefore, after it is transferred into the uterine cavity, implantation occurs within a few hours, very rarely during the first day, but sometimes up to 48 hours. Therefore, to avoid the negative impact of external factors, the woman after the transplantation is recommended to have complete physical and mental rest, which significantly increases the chances of a favorable IVF outcome.

Embryo implantation – IVF involves the transfer of five or three day old embryos, which depends on many factors. If, during in vitro fertilization, several eggs are fertilized, then three-day-old eggs should be replanted, or if the eggs die after fertilization, when their viability is reduced, and also if during previous IVF attempts they died on the fourth or fifth day. At the same time, it is still in the uterine cavity in a free state during the day, and then implantation only occurs.

The sensations during embryo implantation after IVF are expressed differently in all women, while some may have symptoms of its manifestation, while others do not notice them.

What are the main symptoms of embryo implantation after IVF? Objectively, there are no symptoms of embryo implantation, but many women indicate subjective sensations during implantation. Signs of implantation after IVF are associated primarily with changes in a woman’s hormonal levels, leading not only to the manifestation of subjective symptoms of pregnancy, but also worsens her general well-being.

Signs of embryo implantation after IVF

The main signs of embryo implantation into the uterus after IVF appear after a day or two. Among them, the following are widely used:

• minor pain in the lower abdomen of a pulling nature, which may be the result of instrumental embryo transfer and microtrauma
• low-grade fever and an increase in basal temperature above 37 degrees
• scanty spotting bloody discharge from the genital tract
• nausea and sometimes the development of vomiting, up to a change in taste properties
• Moderate weakness, irritability, bad mood
• breast engorgement
• metallic taste in mouth.

In most cases, the first signs of embryo implantation after IVF appear only at the end of the second week after the transfer procedure. And only some women who are looking for symptoms of pregnancy may feel them much earlier.

When is an ultrasound performed after IVF?

Embryo implantation after IVF is in most cases late. While with natural fertilization, implantation occurs 7-10 days after ovulation, and if it occurs on the 6th or 7th day after ovulation, we should talk about its early form, and, accordingly, implantation after 10 days from the moment of ovulation indicates late implantation

Implantation of the embryo into the uterus during IVF is on average observed 2–3 days after replantation, which depends on the presence or absence of an outer membrane in embryos, which three-day-olds always have, but five-day-olds do not have it and, accordingly, the implantation process begins earlier in them, which improves the likelihood of pregnancy.

Late IVF embryo implantation

Late implantation during IVF occurs on the tenth day or later, which is associated with such individual characteristics of the female body, when ovulation occurs late, with anomalies in the development of the fallopian tubes with partial obstruction, which lengthens the time the fertilized egg is in it and, therefore, the implantation process, as well as with abnormalities of embryo development that can be excluded using an additional pre-implantation preparation procedure.

Late implantation after three-day IVF is more common, while late implantation of five-day IVF during IVF is much less common, which is due to the presence or absence of a dense membrane around the zygote, which three-day olds always have and requires additional time to dissolve, which delays the implantation process. This is due to enhanced hormone therapy and adaptation of the embryo to new living conditions.

Late implantation: IVF often uses cryopreservation of eggs, which does not affect the development of the embryos. In most cases, the phenomenon of late implantation occurs.

Late implantation of the embryo during IVF and hCG after it, after six days, begins to be produced by the cells of the corpus luteum, which makes it possible to confirm the presence of pregnancy in 100% of cases using a blood test, and only by the level of hCG in dynamics can one judge a favorable outcome of pregnancy.

Late implantation of the embryo after IVF and hCG, which is a diagnostic criterion for successful fertilization, may lag behind the norm, which does not always require panic and concern, since only a reproductologist can reliably understand this situation and prescribe treatment aimed at maintaining the pregnancy.

HCG level during late implantation: IVF does not always make it possible to become happy parents on the first try, since implantation sometimes may not occur, even if the woman followed all the doctor’s instructions. What is this connected with?

The reasons for the lack of implantation during IVF are varied, but are primarily due to the pathology of the woman’s body or violations of the embryo itself and the technique of its transfer. On the part of the woman, this is most often associated with hormonal imbalance, since a deficiency or excess of one of the hormones leads to a decrease in the chances of implantation, as well as the presence of disorders on the part of the immune system, which lead to the perception of the embryo as foreign. The success of implantation is also influenced by the timing of embryos at which they are placed in the uterine cavity, since the higher their timing, the greater the likelihood of implantation. If the replantation is carried out without taking into account the implantation window, then the chances of implantation are practically absent. Sometimes implantation does not occur due to abnormalities of the embryo, or it occurs, but in the early stages it freezes or spontaneous abortion occurs. The thickness of the endometrium also significantly affects implantation, since a very thin (less than 7 mm) or very thick (more than 13 mm) endometrium reduces the chances of a favorable IVF outcome.

So, successful implantation of an embryo, the sensations that a woman feels after IVF do not always indicate a positive result of the technique. In this case, a 100% result is given by the level of hCG in the blood, which reliably indicates the onset of pregnancy, and only by its growth and dynamic increase can one judge the development of the ongoing pregnancy. To increase the likelihood of implantation, you should not perform physical activity for at least 10 days, since implantation is possible during this period, exclude sexual intercourse and psycho-emotional experiences, good nutrition and daily routine also create favorable conditions for implantation of embryos during IVF. And natural childbirth after IVF is no different from normal.

If you are faced with an infertility problem that cannot be corrected by medication or surgery, then you should register infertile couples on our website and apply for a free IVF program under the compulsory medical insurance policy, which will enable you to become happy parents. Good luck to you!

Under favorable conditions, seven days after fertilization of the egg, pregnancy occurs. But, in some cases, this may not happen, due to the fact that implantation of the embryo did not occur. Expectant mothers are interested in why the embryo does not attach to the uterus and what are the reasons.

Time for embryo attachment

For pregnancy to occur, the fertilized egg must develop into a zygote and implant in the uterus. After this, it can be considered an embryo. In order for an embryo to take root in the uterus, its walls must be ready to receive it.

According to doctors, conception can be early or late. With early implantation, which occurs no later than seven days after ovulation, the female body is not yet prepared to receive the embryo; the endometrium does not have the required thickness. But such cases happen infrequently. Late attachment usually occurs on the tenth day after fertilization. This period is considered the most favorable when carrying out the IVF procedure.

In a natural pregnancy, the implantation of the fertilized egg takes at least 48 hours, and they are decisive.

If, at this time, the woman’s body perceives the embryo as a foreign body, the embryo may not attach to the uterus, rejection will occur and menstruation will occur. A woman is considered pregnant after the implantation and consolidation of the fertilized egg in the uterus. This takes from one to three days.

In the protocol, the future embryo develops outside the female body, it is implanted when it is already mature, and it is able to take root faster than in a natural pregnancy. This is the difference between IVF and natural conception. Embryos aged 3–5 days have the highest survival rate.

Factors that interfere with implantation

With artificial insemination, pregnancy does not occur in all cases. In order to determine why there is no implantation, doctors find out all the reasons for the embryo not attaching to the uterus during IVF. Sometimes, the egg does not attach to the uterus and conception does not occur.

The reasons for unsuccessful embryo implantation are:

1. the presence of endometriosis, fibroids;
2. too thick or thin layer of the endometrium, the thickness of which is ideally from 10 to 13 millimeters;
3. a large number of abortions;
4. genetic abnormalities in the embryo that do not allow it to attach;
5. low levels of the hormone progesterone, which is responsible for creating conditions for fetal development.

Compliance with the last point is of no small importance.

For 12-14 days after the transfer, the woman is advised to follow a gentle regimen, avoid physical activity, and avoid stressful situations.

Lack of implantation during IVF:

• low-quality biomaterial;
• pathological changes in the endometrium;
• hydrosalpinx tubes;
• unqualified support during the protocol;
• ignoring doctor's orders.

What happens if the embryo does not attach to the uterus? If the fertilized egg does not attach, the so-called spontaneous termination of pregnancy occurs at a very short time. Sometimes, a miscarriage occurs after implantation, when the body begins to produce the pregnancy hormone and the test shows a positive result.

Attachment of the embryo

The beginning of the natural implantation period is considered to be the time when an embryo with at least 16 cells enters the wall of the uterus and the egg enters the mucous membrane.

The attachment of the fertilized egg in the protocol differs from natural conception in that it is more quickly implanted.

How the embryo attaches to the uterus during IVF:

• in the first two days, a zygote is formed from the oocyte, from which an embryo has four cells by the end of the second day;
• on the third day there are already eight cells, the embryo is ready for transfer, but the likelihood of pregnancy due to its immaturity is low, and further cultivation occurs to the blastocyst stage, which occurs on the fifth day. This period is considered the best for transfer;
• after replantation, within 48 - 72 hours, under favorable conditions, the fertilized egg attaches to the walls and begins to grow, as in a natural pregnancy. But, in order for this to happen, the embryo itself must have the ability to further develop.

It is possible to transfer the blastocyst to the uterus at the age of 2-4 days, but this is impractical, and the chances of a successful pregnancy are low. After implantation, you need to wait at least two weeks to confirm a positive result.

The fertilized egg is attached in different places. If the embryo is attached high in the uterus, it means that it has implanted close to its bottom, which is the most favorable for its further development. If the embryo does not attach, another menstruation occurs, and the fertilized egg is released along with the discharge.

Helps in the attachment of the embryo

Many patients who have entered into the protocol are interested in the question of why the embryo does not attach to the uterus during IVF. This is influenced by many factors, to eliminate which additional treatment is carried out, increasing the chances of a successful transfer.

The reason that the fetus has not implanted may be poor quality of the endometrium with increased or decreased immune activity. In order to help the embryo implant in the uterus during IVF, additional procedures are prescribed that have a positive effect on the condition of the endometrium and help further implantation.

For example, with a deficiency of immune activity, injection of seminal fluid into the uterus, local irritation of the mucous membrane helps, and if it is too high, intravenous administration of immunoglobulin, follicular fluid into the uterus and other methods.

What to do if the embryo does not attach to the uterus? There are several factors that influence the fact that the embryo cannot attach. These are pathologies of the female reproductive system, gynecological diseases and genetic abnormalities in the fertilized egg itself. In this case, a detailed ultrasound examination and tests are prescribed to identify the causes. If attempts to get pregnant naturally are constantly unsuccessful, it is recommended to use the IVF procedure. But it is important to remember that it does not provide a complete guarantee.

When will the embryo come out if it has not attached to the uterus? If the embryo does not take root, it means that the fertilized egg has stopped in its development and will be released from the body during the next menstruation. If the desired pregnancy does not occur, there is no need to despair. You should contact highly qualified specialists who will help you find out all the reasons that are preventing embryo implantation and prescribe the necessary treatment.