What Is Single Embryo Transfer? Overview, Benefits, and Expected Results
Single embryo transfer (SET) is an assisted reproductive technology (ART) that enables fertility specialists to implant just one laboratory-created embryo into the uterus, maximizing the likelihood of success while reducing the potential for multiple births. SET is typically performed as part of an in vitro fertilization (IVF) cycle and offers couples a way to increase their chances of achieving a successful pregnancy without the risks associated with twins or triplets.
What Is Single Embryo Transfer?
Single Embryo Transfer (SET) is an assisted reproductive technology (ART) procedure in which just a single laboratory-created embryo is implanted into the uterus, as opposed to traditional embryo transfer where two or more embryos are transferred. SET is one of the most successful IVF treatments available and is typically performed on patients who are considered at lower risk for miscarriage or implantation failure.
The SET procedure involves the use of an IVF cycle, during which a few eggs are extracted from the ovaries and fertilized with the sperm outside of the body. The resulting embryos are then monitored for growth and, after a few days, one of the healthiest embryos is selected to be implanted into the uterus.
Benefits of Single Embryo Transfer
SET offers a number of benefits for both patients and fertility clinics. Here are a few of the most notable advantages of single embryo transfer:
- Reduced odds of multiple births – Transferring more than one embryo increases the chance of multiple births, a scenario that is often associated with higher risks for the mother and the unborn babies.
- Reduced chance of miscarriage – By transferring only one healthy embryo, the chances of miscarriage are lower than with multiple transfers.
- Significantly lower cost – Without having to pay for extra fertility drugs or medical interventions for a multiple pregnancy, SET is generally less expensive than traditional embryo transfer.
- Shorter pregnancy – SET has been shown to decrease the duration of a successful pregnancy.
- High success rates – The success rate of single embryo transfer is often higher than that of traditional IVF cycles.
- Improved chances for future IVF cycles – By transferring fewer embryos, there is a better chance of using these embryos for a future IVF cycle.
What Are The Expected Results of Single Embryo Transfer?
The success rate of SET is closely related to the patient’s age and the quality of the embryos. Generally speaking, it is believed that the chance of achieving a successful pregnancy is higher with SET when compared to transferring two or more embryos.
When SET is performed on younger patients (i.e. under 35), the success rate is as high as 40% or more. On the other hand, the success rate of SET in women aged 35–39 is generally around 30%, while it decreases further for women aged 40 and above.
What Factors Should Be Considered Before Opting for Single Embryo Transfer?
As with all ART treatments, SET is not ideal for everyone and patients should consult a fertility specialist to decide if they are a good candidate for SET. Some of the most important factors to consider before opting for SET include:
- Age – As previously mentioned, the success rate of SET decreases with age and fertility specialists may not recommend SET to patients over 35.
- General health – Fertility clinics typically require patients to undergo a thorough medical assessment before they can proceed with SET.
- Embryo quality – SET is usually recommended for those who have healthy embryos with good potential for implantation.
- Cost – SET is generally more expensive than traditional IVF, so couples should calculate their budgets accordingly.
- Risks – As with any medical procedure, SET carries certain risks and patient should evaluate the potential benefits and risks of SET before deciding to proceed.
Single Embryo Transfer is an assisted reproductive technology that offers couples an opportunity to increase their likelihood of achieving a successful pregnancy without the risks associated with multiple births. It involves the implantation of a single laboratory-created embryo into the uterus as part of an IVF cycle and has the potential to reduce cost, miscarriage, and the length of the pregnancy.
SET is typically most successful in younger patients, but couples should speak to their fertility specialists to decide if SET is an appropriate option for them. Factors to consider include age, general health, embryo quality, cost, and possible risks.
التعريف والنظرة العامة
A single embryo transfer is one of the procedures used in assisted reproductive technology for patients with fertility problems. This particular procedure refers to the process of transferring one embryo and placing it in the fallopian tube or uterus. The embryo is chosen from among a larger group and may be either a fresh embryo resulting from a current in vitro fertilization (IVF) cycle or a cryopreserved embryo that resulted in a past IVF cycle.
Couples sometimes specifically request for a single embryo transfer to avoid the possibility of multiple births that have been associated with certain risks both to mother and child. Choosing a single embryo transfer can help ensure that multiple births will not occur without adversely affecting the couple’s chances of conceiving.
من يجب أن يخضع للنتائج المتوقعة
Opting to have a single embryo transfer is beneficial for women who are:
- Younger than 35 years old
- Able to produce at least three high quality embryos on the 3rd day of IVF
- On their first IVF attempt with no history of failed cycles
Women who meet the above criteria are the ones faced with a higher possibility of having multiple pregnancies. This procedure will thus help couples avoid the risks of multiple pregnancies.
Each woman faced with the choice to have one or multiple embryos transferred should consider the above factors, as well as her and her partner’s practical and personal limits regarding raising a child. For example, women who wish to breastfeed exclusively may find it more difficult to achieve this ideal if they have twins or triplets. Some financial and practical aspects of childcare should also be taken into consideration.
Multiple حمل has also been associated with several risks both to mother and child. Women who are having twins or triplets face a higher risk of pregnancy complications, such as إجهاض, pre-eclampsia, hypertension, and gestational diabetes. They also have a greater tendency to require a caesarean delivery, and will be faced with a greater risk of hemorrhage and anemia after childbirth. Some studies also link the increased challenge of caring for multiple babies at the same with a higher risk of falling into postpartum كآبة.
The babies born of multiple pregnancies are also not completely protected from risks. Twins and triplets tend to have low birth weights than singletons, and they also face a higher risk of being born prematurely. Thus, opting for an SET procedure also increases the chance of giving birth to a healthy baby.
But while single embryo transfer helps avoid the above risks to mother and child, the procedure is not known to lower the woman’s chance of successful conception, especially when certain factors are in place. In fact, the procedure gives a woman comparable chances of conceiving as one who choose to proceed with a multiple transfer, as long as:
- The mother is a suitable candidate for this elective procedure
- The embryo with the best quality is used. (Since only one embryo will be transferred, the process of selecting the best embryo becomes more important)
كيف يتم إجراء العملية؟
In a single embryo transfer, embryologists will choose the best quality embryos from among those produced during a fresh or previous IVF cycle. The other embryos are then frozen for storage. Storing an embryo will not lower its quality; in fact, if an embryo is of good quality, it is more likely to survive the whole process of freezing and thawing.
Once the embryo is chosen, it can be implanted back into the uterus. However, the time at which the embryo is transferred may have an effect on the procedure’s success. Most experts wait until an embryo is at its blastocyst stage, which occurs on the 5th or 6th day, before implanting it to increase the chances of success.
Embryos are transferred back to the uterus by passing them through a catheter that is inserted into the vagina. The physician then proceeds to pass the catheter through the cervix and into the uterus, with the whole process guided by an ultrasound image. The process is similar to a cervical screening exam and does not typically require any form of anesthesia. However, if the patient requests, some mild sedation may be provided.
The procedure is followed by a recovery period of 4 to 6 hours during which the patient is asked to relax and remain flat on her back. After this, she can be discharged, with instructions on what follows, particularly her continuous supplementation of progesterone.
المخاطر والمضاعفات المحتملة
A single embryo transfer does not reduce a woman’s chances of successfully conceiving a baby, but it significantly reduces the risk of multiple birth and the risks of multiple pregnancies. Thus, the procedure is considered the safer choice and is free from any serious risks or possible complications.
The procedure itself is a very simple one with very minimal risks, namely:
- Loss of embryo during the transfer
- Implanting the embryo in the incorrect location, such as the fallopian tubes
There is, however, hardly any risk to the health of the patient. At most, the patient may experience some mild cramping. This procedure is actually considered as the simplest step that marks the end of the IVF process, after which the couple only needs to wait for the results.
The Practice Committee of the Society for Assisted Reproductive Technology and the Practice Committee of the American Society for Reproductive Medicine. Criteria for number of embryos to transfer: a committee opinion. Fertil Steril. Jan 2013;99 (1):44-46.
Jackson RA, Gibson KA, Wu YW, et al. Perinatal Outcomes in Singletons following in vitro fertilization: a meta-analysis. Obstet Gynecol. 2004;103: 551-563.