Embryo transfer refers to a step in the aid reproduction process in which the embryo is placed into the female uterus in order to build a pregnancy. This technique (which is often used in conjunction with in-vitro fertilization (IVF)), can be used in humans or animals, where the objective situation may vary.
Embryo transfer may be performed on days two or three days, or later in the blastocyst stage, which was first performed in 1984.
Video Embryo transfer
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Embryos can be "fresh" from the fertilized eggs of the same menstrual cycle, or "frozen", that they have been produced in the previous cycle and undergo cryopreservation of the embryo, and thawed immediately before transfer, which is then termed "frozen transfer embryo" (FET ). The results of using cryopreserved embryos were uniformly positive without an increase in birth defects or developmental abnormalities, as well as between fresh versus frozen eggs used for intracytoplasmic sperm injection (ICSI). In fact, pregnancy rates rise after FET, and perinatal outcomes are less affected, compared with embryo transfer in the same cycle as ovarian hyperstimulation. The endometrium is believed not to be optimally ready for implantation after ovarian hyperstimulation, and therefore the transfer of embryo frozen embryos to separate cycles to focus on optimizing the likelihood of successful implantation. Children born from vitrified blastocysts had significantly higher birthweights than those born from non-frozen blastocysts. When transferring frozen-thawed oocytes, the likelihood of pregnancy is essentially the same whether transferred in a natural cycle or one with ovulation induction.
Maps Embryo transfer
Preparation of the uterus
In humans, the lining of the uterus (endometrium) needs to be precisely prepared so that the embryo can implant. In the natural cycle, embryo transfer occurs in the luteal phase at which the coating is not well developed with respect to the current status of Luteinization Hormone. In the stimulation or cycle in which the "frozen" embryo is transferred, the recipient woman can be given the first estrogen preparation (about 2 weeks), then a combination of estrogen and progesterone so that the layers become receptive to the embryo. The reception time is the implantation window. A scientific review in 2013 came to the conclusion that it is impossible to identify a method of preparing endometrium in frozen embryo transfer as more effective than others.
Limited evidence also supports removal of cervical mucus prior to transfer.
Time
Embryo transfer may be performed after various embryonic culture periods, giving different stages in embryogenesis. The main stage in which embryo transfer is performed is the cleavage stage (days 2 to 4 after co-incubation) or blastocyst stage (day 5 or 6 after co-incubation).
Embryos that reach stage 3 day cells may be tested for genetic or chromosomal specific defects before transfer is possible with a preimplantation (PGD) genetic diagnosis. Transferring at the blastocyst stage provides a significant increase in live birth rate per transfer, but it also confers the decrease in the number of embryos available for embryo transfer and cryopreservation, so that the cumulative clinical pregnancy rate increases with transfer of the cleavage stage. Day transfer 2 instead of 3 days after conception has no difference in live birth rate.
Monozygotic twins do not increase after blastocyst transfer compared with embryonic transfer phase of the hemisphere.
There is a higher likelihood of premature birth (odds ratio 1.3) and congenital anomalies (odds ratio 1.3) among births after reaching the blastocyst stage compared to the cleavage stage. Due to the increased mortality of female embryos due to epigenetic modification caused by expanded culture, blastocyst transfer results in more male births (56.1% of men) than transfers 2 or 3 days (normal sex ratio of 51.5% ).
Embryo options
The laboratory has developed assessment methods to assess the quality of oocytes and embryos. To optimize pregnancy rates, there is significant evidence that a morphological assessment system is the best strategy for embryo selection. Since 2009 where the first time-lapse microscopy system for IVF was approved for clinical use, the morphokinetic assessment system has been shown to increase to further pregnancy rates. However, when all types of time-lapse embryo imaging devices, with or without a morphokinetic assessment system, were compared with conventional embryo assessment for IVF, there was not sufficient evidence of differences in live birth, pregnancy, stillbirth or miscarriage to choose between them.
Procedures
The embryo transfer procedure begins by placing the speculum in the vagina to visualize the cervix, which is cleaned with saline solution or culture medium. The soft transfer catheter is filled with an embryo and submitted to the doctor after confirmation of the patient's identity. The catheter is inserted through the cervical canal and continues into the uterine cavity.
There is good and consistent evidence of the benefits in ultrasound guidance, ie, making a stomach ultrasound to ensure correct placement, ie 1-2 cm from the uterine fundus. There is evidence of a significant increase in clinical pregnancy using ultrasound guidance compared to just "clinical touch". Anesthesia is generally not necessary. Single embryo transfer in particular requires precision and precision in placement within the uterine cavity. The optimal target for embryonic placement, known as the maximum implantation potential point (MIP), is identified using 3D/4D ultrasound. However, there is limited evidence supporting the deposition of embryos in the uterine midportion.
After insertion of the catheter, the contents are removed and the embryo is stored. Limited evidence supports the manufacture of experimental transfers prior to embryo procedures. After expulsion, the duration of the catheter remains in the uterus has no effect on the pregnancy rate. Limited evidence indicates avoidance of negative pressure from the catheter after expulsion. After withdrawal, the catheter is left to the embryologist, who checks for the retained embryo.
In the process of intracallopian zygote transfer (ZIFT), the egg is removed from the woman, fertilized, and then placed in the female oviduct of the uterus.
Simulation procedure
In 2015, the American Society for Reproductive Medicine developed a medical simulation of the Embryo Transfer procedure with Swiss company VirtaMed, designed for physician education and training. Virtual reality simulators, which include simulated ultrasound guides in real-time, were launched at the annual conference of the American Society for Reproductive Medicine.
Embry number
The main problem is how many embryos need to be transferred. Placement of multiple embryos carries the risk of multiple pregnancies. In the past, doctors often put too many embryos in the hope of building a pregnancy. However, the increase in multiple pregnancies has led to a reassessment of this approach. Professional societies and in many countries, legislatures, have issued guidelines or laws to limit the practice of placing too many embryos in an effort to reduce multiple pregnancies. The number of appropriate embryos to transfer depends on the age of the woman, whether it is the first full, second or third cycle IVF effort and whether there is a high-quality embryo available. According to guidelines from the National Institute for Health and Nursing Excellence (NICE) in 2013, the number of embryos transferred in the cycle should be selected as in the following table:
e-SET
The technique of selecting only one embryo to transfer to a woman is called single-elective embryo transfer ( e-SET ) or, when the embryo is at the blastocyst stage, it can also be called a transfer single elastic blastocyst (eSBT) . This significantly reduces the risk of multiple pregnancies, compared with eg Double Embryo Transfer (DET) or double blastocyst transfer (2BT), with twin birth rates of about 3.5% in sets compared with about 38% in the DET , or 2% in eSBT compared to about 25% in 2BT. At the same time, the pregnancy rate is not much different from the eSBT compared to 2BT. That is, the cumulative live birth rate associated with a fresh embryo transfer followed by a single and frozen single embryo transfer is proportional to a single double embryo transfer cycle. In addition, SET has better outcomes in terms of average gestational age at delivery, delivery mode, birth weight, and risk of neonatal intensive care unit than DET. e-SET embryos at the cleavage stage reduced the likelihood of live birth by 38% and multiple births by 94%. Evidence from randomized, controlled trials showed that increasing the number of e-SET attempts (fresh and/or frozen) resulted in a cumulative live birth rate similar to that of a DET.
The use of single embryo transfer is highest in Sweden (69.4%), but as low as 2.8% in the United States. Access to public funding for ART, the availability of good cryopreservation facilities, an effective education on the risks of multiple pregnancies, and legislation appear to be the most important factor for the use of single embryo transfer regions. Also, personal choice plays an important role because many subfertile couples have a strong preference for twins.
Adjunctive procedure
There is limited evidence to support the use of mechanical closure of the cervical canal after embryo transfer.
There is not sufficient evidence to support a certain amount of time for women to remain lying down after embryo transfer.
There is no evidence of benefit in terms of live birth rates using hyaluronic acid as a compliance medium for embryos. There is also no evidence of the benefits of having a full bladder, removal of cervical mucus, or flushing of the endometrial or endocervical cavities at the time of embryo transfer. Additional antibiotics in the form of amoxicillin plus clavulanic acid do not increase the rate of clinical pregnancy compared with no antibiotics.
For liquefied embryos or embryo transfer from egg donation, no prior ovarian hyperstimulation is required for the recipient prior to transfer, which may be performed in a spontaneous ovulatory cycle. However, various protocols exist for the transfer of frozen-thawed embryos as well, such as protocols with ovarian hyperstimulation, protocols in which the endometrium is made artificially by estrogen and/or progesterone. A Cochrane review in 2010 from a randomized study came to the result that there is generally insufficient evidence to support the use of one intervention in preference to another, but with some evidence that in cycles in which the endometrium is artificially created by estrogen or progesterone, additional drugs that suppress hormone production by the ovaries such as the continuous administration of gonadotropin releasing the agonist hormone (GnRHa). For egg donations, there is evidence of lower pregnancy rates and higher cycle cancellation rates when progesterone supplementation in recipients begins before for oocyte removal from donors, compared with the day of oocyte retrieval. or the day after.
Seminal fluid contains several proteins that interact with the cervical epithelial cells and the uterus, which encourages active gestational immune tolerance. There are significantly increased results when women are exposed to seminal plasma around the time of embryo transfer, with statistical significance for clinical pregnancy, but not for ongoing pregnancies or live birth rates with limited data available.
Followup
Patients usually start progesterone treatment after egg-taking (also called oocytes). While daily intramuscular injections of progesterone-in-oil (PIO) have become standard administration routes, PIO injections are not FDA approved for use in pregnancy. A recent meta-analysis shows that intravaginal routes with the appropriate dosage and frequency of dosing are equivalent to daily intramuscular injections. In addition, a recent case study comparing vaginal progesterone with PIO injections suggests that live birth rates are almost identical to both methods. Duration of 11 days of progesterone results in a similar birth rate with longer duration.
Patients are also given estrogen medication in some cases after embryo transfer. Pregnancy tests are done usually two weeks after egg collection.
Third party reproduction
It is not necessary that embryo transfer is performed on women who provide eggs. So, another woman whose uterus is properly prepared can receive an embryo and become pregnant. Embryo transfer can be used where a woman who has an egg but does not have a uterus and wants to have a biological baby; she will need the help of a pregnant carrier or a substitute to carry the pregnancy. Also, a woman who does not have an egg but the uterus can use IVF egg donor, in this case another woman will give the egg for fertilization and the resulting embryo is placed into the patient's womb. Fertilization can be done using female partner sperm or by using donor sperm. Embryo 'Spare' created for other couples undergoing IVF treatment but then surplus for the couple's needs can also be transferred (called donation embryo). Embryos can be specifically made by using eggs and sperm from a donor and these can then be transferred to another woman's uterus. A replacement can carry an infant produced by embryo transfer to another partner, although neither he or the commissioning partner is biologically related to the child. Third-party reproductions are still controversial and regulated in many countries. People entering gestational surrogacy settings should understand the kind of completely new relationship that does not fit the traditional script we use to categorize relationships as kinship, friendship, romantic partnership or market relationships. Substitutes have the experience of bringing the babies they draft as not from their own relatives, while the dreaded mother has the experience of waiting through nine months of pregnancy and transitioning to the mother from outside the pregnant body. This can lead to a new conceptualization of the body and self.
History
The first transfer of embryos from one human to another resulted in a pregnancy reported in July 1983 and then led to the announcement of the first human birth of 3 February 1984. This procedure was performed at UCLA Harbor Medical Center under the direction of Dr. John Buster and the University of California at Los Angeles School of Medicine.
In the procedure, a newly developed embryo was transferred from a woman who had been conceived by artificial insemination to another woman who delivered a baby 38 weeks later. The sperm used in artificial insemination comes from the female husband who gave birth to her baby.
This scientific breakthrough sets standards and becomes a change agent for women suffering from infertility woes and for women who do not want to pass on genetic disorders to their children. Transfer of the donor embryo has given women a mechanism to conceive and give birth to a child that will contain the genetic makeup of their husbands. Although transfers of donor embryos as currently done have evolved from the original non-surgical method, it now accounts for about 5% of births recorded in in vitro fertilization.
Before this, thousands of women were barren, having adoption as the only path to parents. It sets the stage to allow open and frank discussion about embryo donations and transfers. This breakthrough has given way to the donation of human embryos as a common practice similar to other donations such as blood and major organ donations. At the time of this announcement the event was captured by the main newscaster and sparked a healthy debate and discussion of this practice that impacted the future of reproductive medicine by creating a platform for further advancement in women's health.
This work establishes the technical foundations and legal-ethical framework around the clinical use of human oocytes and embryo donations, the main clinical practice, which has evolved over the past 25 years.
Effectiveness
An updated Cochrane systematic review in 2012 shows that blastocyst stage transfer is more effective than phase 2 (3 or 3) cleavage in assisted reproductive technologies. This shows a small increase in live birth rate per couple for blastocyst transfer. This means that for a typical 31% level in a clinic that uses the initial cleavage cycle cycle, that number will increase to 32% to 42% of live births if the clinic uses blastocyst transfer.
Embryo transfer in animals
The embryo transfer technique enables high quality female animals to have a greater influence on the genetic advancement of herds or herds in much the same way as artificial insemination that allows greater use of the superior male. ET also allows the use of sustainable animals such as competition horses to keep practicing and showing, while producing foals. The common epidemiological aspects of embryo transfer suggest that embryo transfer provides an opportunity to introduce genetic material to livestock populations while greatly reducing the risk of transmission of infectious diseases. Recent developments in embryo sexing before transfer and planting have great potential in the livestock and other animal husbandry industries.
Embryo transfer is also used in laboratory rats. For example, embryos of genetically engineered strains that are difficult to breed or costly to maintain can be stored frozen, and only thawed and implanted into quasi-dam if necessary.
Transfer of frozen embryo in animals
The development of various methods of cryopreservation of cow embryo improves highly efficient embryo transfer techniques, no longer dependent on the immediate readiness of the intended recipient. The pregnancy rate is slightly lower than that achieved with fresh embryos. Recently, the use of cryoprotectants such as ethylene glycol has enabled direct transfer of bovine embryos. The world's first live cow fowl produced under tropical conditions by Direct Transfer (DT) from frozen embryos in the frozen media of ethylene glycol was born on June 23, 1996.Dr.Binoy Sebastian Vettical of Kerala Animal Husbandry Development Council Ltd. has produced frozen stored embryos in Ethylene Glycol freezes the medium with a programmable slow freezing technique (SPF) and is transferred directly to the cow receiver immediately after liquefying the frozen straw in water for this calf's birth. In one study, in vivo produced cow's embryos stored in frozen ethylene glycol media transferred directly to recipients in tropical conditions and achieved a 50 percent pregnancy rate. In a North American embryo transfer industry survey, embryo transfer success rates from direct embryo transfer are as good as those achieved with glycerol. In addition, in 2011, more than 95% of frozen-thawed embryos were transferred by Direct Transfer.
References
External links
- How embryo transfer works as part of fertility treatments
- The blastocyst transfer process - an embryo transfer form
- One-by-one websites - benefits from Single Embryo Transfer
Source of the article : Wikipedia
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