Innovative techniques are persistently growing for infertility treatment. The evolving industry is giving great expectations to most of the people who want to experience parenthood. It seems exciting to be a mother of more than 1 baby and is often a happy moment for every parent. But in multiple pregnancies, there is a risk of complications like premature birth, congenital abnormalities, and mother will more likely to have health issues like gestational diabetes, anaemia, and high blood pressure. In addition to this, a premature baby needs special care in the Intensive care unit (ICU). So, single embryo transfer (SET) is good option to overcome these problems. Single-embryo transfer (SET) is a process in which one high-quality embryo is placed into the uterus. So, the main focus is to reduce the twin rates in pregnancy by using the single embryo transfer technique.
In the recent years, SET has extensively accepted due to the reason that it reduces the possibility of twins and triplets and also it is safe for both baby and mother. According to the American Society of Reproduction Medicine, single embryo transfer should be considered for patients with favourable prospects usually women who are under the age of 35 or younger with good quality eggs.
Single Embryo transfer (SET) is done when the embryo is at the blastocyst stage. And it is the stage when the best quality embryos can be identified more accurately. A blastocyst stage transfer is a more viable embryo for transfer which reduces the multiple pregnancies. Nowadays, the embryo screening technologies are highly developed, through which embryologist are able to get best single embryo with the goal of achieving a good singleton pregnancy and which reduces the possibilities of multiple gestation and miscarriages.
Through, cryopreservation technology embryos are preserved in frozen condition with no risk even after they have been cultured in the lab to the blastocyst stage. With the help of advanced tools, embryologists can provide the appropriate environment for embryos to grow, as well as methods to recognize that embryo which is likely to develop a baby. This contributes to the probability of success on the first embryo transfer as well as successive transfers.
Due to the advancement of the technology, the majority of patients are able to conceive through single embryo transfer. Success rates of Single embryo transfer (SET) have increased considerably over the past 5 years, making it nearly as likely to achieve a successful pregnancy embryo as with two or more embryos.
A very common question being asked after an IVF failure, in spite of transferring good quality embryos. In fact a very frustrating moment for the infertility specialist also.
The couple and the treating specialist usually develop high expectations after seeing beautiful embryos on the monitor. But reality is an implantation rate of 25-40%.
Another tendency is to blame the uterus as the cause of failure as embryos seemed very good at the time of transfer. But this is not true.
In 2/3 of the implantation failures the uterine receptivity is the major causes and in approximately 1/3 the embryo quality, as all good looking embryos are not genetically normal.
Implantation failure doesn’t always mean an uterus with some inherent defect or permanent inability to implant and grow a baby. As many of these patients may conceive with donor oocytes. The major cause of implantation failure in self cycle is hormonal effect on the endometrim due to stimulation process used on the ovaries. They alter the intrauterine environment with which the embryos interact.
Now few solutions to these problems which can work to some extent. Certain modifications in the stimultation protocols and freezing all resulting embryos and transfer after some time have promising results.
Whenever a sudden shift is made from fresh embryo transfer to frozen embryo transfer the couple usually have many queries in mind. So, let’s evaluate both and see pros and cons.
Fresh embryos transfer is undergoing ovarian hyper stimulation making of embryos and transferring resultant embryos to uterine cavity in same cycle. In frozen embryo transfer first two steps of controlled ovarian hyper stimulation and process of IVF/ICSI are same but the resultant embryos are frozen using vitrification techniques and not transferred in same cycle. They are thawed and then kept uterine cavity after preparing the uterine cavity.
In patients who are normal or hyper responders the frozen embryo transfers are known to have better results than the fresh embryo transfer . The reason can be that due to ovarian hyper stimulation and high levels of estrogen may have negative impacts on the endometrial receptivity. In some cycles another hormone called progesterone may also be raised, which again decreases embryo implantation rate. Whereas in frozen embryo transfer the body and uterus have already recovered from the impact of hormonal disturbance and hence more receptive.
Because of their reason in patient with PCOS the frozen embryo transfer is associated with higher live birth rate. It also reduces complications like ovarian hypertimulation in these patients.
Another reason where we make a sudden shift from fresh to frozen embryo transfer are when the ovarian stimulation part is good but the endometrial thickness fails to reach an optimal level.
So because of the above reasons we are moving towards more frozen transfer than fresh transfers in self cycle.