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.