To increase your in vitro fertilization success

1. Auxiliary nesting

More than half of the couples who use assisted reproductive techniques do not become pregnant even though the embryo develops. The reason why pregnancy does not occur despite fertilization is probably due to the implantation phase of the embryo in the uterus.

Following the placement of the embryo in the uterus, various events occur; the embryo continues to divide and grow. When it reaches a certain size, it tears the membrane surrounding it (zona pellucid) and settles deep into the tissue within the uterus called the endometrium, where it continues to grow.

It is accepted that the most important reason why pregnancy does not occur is that the embryo cannot get out by tearing this membrane and therefore cannot settle on the uterine wall. To solve this problem, a small hole is made in this membrane surrounding the embryo using chemical or mechanical methods before the transfer process, allowing the embryo to rupture this membrane and settle on the uterine wall. Scientific studies show that there is a noticeable increase in pregnancy rates with this method. This technique is briefly applied as follows: first, the embryo is fixed by sucking it from its wall with the help of a microscopic tube, and then a hole is made at two points by passing tangentially through the embryo wall with a microscopic needle. While the embryo continues to grow in the uterus, it can pierce the membrane at these weak points.

2. Endometrial co-culture
In this method, a piece taken from the uterus after ovulation in the month before the treatment is artificially developed by cell culture in a laboratory environment. Embryos are placed on this layer and their growth is monitored. Co-Culture is a method that was introduced especially in the early 1990s because embryo culture environments did not support embryos until advanced developmental stages, and today it is not used much outside of research. There is a study showing that pregnancy rates increase when co-cultures are used in couples with recurrent in vitro fertilization failures (Spandorfer 2003). To date, similar results have not been published by other researchers. The most important weakness of the study is that the so-called randomized groups were not randomly selected. The most important reason for the loss of popularity of co-cultures is the method used in recent years to improve embryo development at 5-6 stages. The reason for this is the emergence of successive cultural environments that support it until today. In these environments, the rate of embryos reaching the blastocyst stage is no different or even better than in co-culture. We do not use co-cultures, both routinely and in couples with unsuccessful attempts, as their effectiveness has not been proven.

3. Embryo bonding
There are studies showing that pregnancy rates increase with the use of an adhesive called embryo glue, especially in older women and couples with repeated in vitro fertilization failures. In two studies we conducted in our own clinic, we found that embryo adhesive was beneficial in selected couples (female age over 39 and repeated in vitro fertilization failure). We recommend its use in this group of patients. However, couples should not perceive this as a miracle.

4. Blastocyst culture
Recently, using developed medium systems, embryo viability has been further extended in the laboratory environment, and accordingly, 5th or 6th day transfers, which provide higher pregnancy rates, have become common in in vitro fertilization centers. This is called blastocyst transfer. The last stage the embryo reaches before attaching to the mother's womb is called the blastocyst stage. Better results were obtained compared to second-third day transfers.

The advantages of blastocyst transfer are:

• Ability to select embryos with better developmental potential
• Reducing the possibility of multiple pregnancy by transferring fewer embryos with high viability
• Better observation of embryo development
• Ability to return embryos at the blastocyst stage, when they have the highest developmental potential
• To be able to perform trophectoderm (inner cell layers of the blastocyst) biopsy in centers that practice preimplantation genetics and to eliminate ethical problems since this tissue is not embryonic.
• It provides opportunities for methods to examine embryo viability.

  
  5. Preimplantation genetic diagnosis
  Preimplantation Genetic Diagnosis (PGD) is a new genetic diagnosis method that allows couples with genetic diseases in their families or interstitial families who have not responded to the treatments to have a healthy baby using the in vitro fertilization method. In this technique, the embryos obtained from the couples are examined one by one, the genetically healthy embryos are separated from the abnormal embryos, and the embryos determined to be genetically normal are transferred to the expectant mother. In this way, pregnancy is controlled from the very beginning for couples who are at high risk of having a child with a genetic disorder. One of the main reasons for negative results in IVF is miscarriages due to chromosomal anomaly. For this reason, PGT is recommended for older expectant mothers, especially because of the high rate of chromosomal anomalies found in the oocytes of older IVF patients. In addition, pre-pregnancy analysis of genetic diseases such as thalassemia and sickle cell anemia, which are frequently seen in our country, can also be performed with PGT. Developing genetic techniques and increased access to information have made it easier for couples to apply to health centers about PGT and other prenatal diagnosis methods. IVF, whose main aim is to reunite families with healthy babies, has taken another step towards success with the application of Preimplantation Genetic Diagnosis.

  6. Embryo freezing
  Freezing human gametes and embryos is of great importance in in vitro fertilization practice. The general approach to minimize the risk of multiple pregnancy in in vitro fertilization applications is to transfer a maximum of three embryos. In this case, the first question that comes to mind is how to evaluate the excess embryos obtained. Freezing the excess embryos obtained in this way provides both an economic and psychological advantage to the patient. Additionally, when frozen embryos are transferred, the patient does not need any treatment. Embryo freezing can also be considered as a procedure that increases the chance of success in in vitro fertilization applications.

  Embryo freezing and thawing process involves cooling the embryos after equilibrating them with chemical substances (cryoprotectants) and storing them in liquid nitrogen at -196°C. After thawing, they are removed from the cryoprotectant environment and placed in special culture environments to ensure further development. Both procedures must be done very carefully. In routine in vitro fertilization and microinjection applications, pregnancy rates with embryo freezing vary between -25. If pregnancy is achieved in the same cycle and the remaining embryos are frozen, this time the pregnancy rate is the same. Embryos frozen by obtaining permission from the couples can be stored in liquid nitrogen for three years under a law that came into force in Turkey in 1997.

  7. Removing the tubes
  In some cases where the tubes are blocked, fluid accumulates in them (hydrosalpinx), which reduces the success rate of in vitro fertilization to 0 levels. If the inside of the tubes are found to be filled with fluid on ultrasonography, removing the tubes with the laparoscopic technique before in vitro fertilization allows the couple to try for pregnancy without decreasing their chances of pregnancy.

  8. Microdissection TESE
  The sac containing the testicles and the sheath called tunica albuginea surrounding each testicle are opened with a small incision. Testicular tissue is examined with a microscope and samples are taken from large areas. The process is completed by sewing the cut sections. There are publications suggesting that this method causes less damage to testicular tissue. With surgical sperm retrieval methods, sperm can be found in 100% of obstructive azoospermia cases and in 100% of nonobstructive azoospermia cases. In cases of obstructive azoospermia, the viability rates of sperm after freezing and thawing and the pregnancy rates obtained with the use of these sperms are quite good. However, freezing and reusing sperm obtained in cases of nonobstructive azoospermia is a controversial issue. A significant portion of the sperm obtained from these patients has structural defects and may not be able to withstand the stress of the freezing and thawing process. However, in case sperm cannot be found in subsequent procedures, it may be recommended to freeze and store suitable sperm very selectively. We believe that using fresh sperm as much as possible increases success in this group.

  For obstructive azoospermia cases, patients who underwent up to seven procedures have been reported in the literature, and sperm was obtained in each of these procedures. In cases of nonobstructive azoospermia, patients who underwent TESE up to 6 times and obtained sperm were reported, provided that sperm was found in previous TESEs. Pregnancy rates obtained with repeated TESE applications are not different from the pregnancy rates obtained in the first application. It has been reported that 25% of nonobstructive azoospermia patients in whom mature sperm were not found in the first TESE were found in the second application.