Something you will hear much about when you enter into IVF at our center is “Single Embryo Transfer.” Dr. Springer has converted to this practice in the vast majority of patients under 38 years of age.
In the early years of IVF, our technology was somewhat primitive compared to today. As such, it was more difficult to grow good quality embryos. Unfortunately, it was necessary to transfer back into the uterus multiple embryos in order to achieve reasonable pregnancy rates. A tremendous downside to the practice of transferring several embryos was the alarming numbers of twins, triplets and even higher order multiple pregnancies.
As one could imagine, over the past nearly 40 years, we have made gigantic leaps in our ability to culture and transfer good quality embryos. And as embryo quality has improved, we have been able to achieve good pregnancy rates by transferring fewer embryos. For the past several years it has been common practice to transfer two embryos in young women. Although this eliminated most triplets or higher, as recently as 2013 twin pregnancy rates were still above 30% in most clinics. In a separate blog I have discussed the significant complications we see with many twin pregnancies. See “The Trouble with Twins”.
Because of the excessively high twin rate, many clinics, over the past few years, have introduced the concept of single embryo transfer. At CRH we were one of the first in the area to aggressively approach single embryo transfer. In 2016 in women under 38, 80% of all our transfers were a single embryo. As such, our twin rate has fallen from over 30% in 2013 to a mere 6% in 2015!
Even in the best of IVF labs and clinics, however, we cannot achieve the level of success we would all hope for simply by choosing am embryo based on looks alone. As such, we will sometimes recommend embryo biopsy for PGS, preimplantation genetic screening, to further increase pregnancy rates per transfer. More on this in my blog, “The pros and cons of embryo biopsy”.