Embryos have been successfully frozen (cryopreserved) since the early 1980’s. Worldwide literature has confirmed that there is no increase in birth defects in children born from frozen embryos. The pregnancy rates with frozen embryos have been increasing steadily. For the past few years, we have been freezing embryos at the blastocyst stage (5 or 6 days after egg retrieval) using a technique called vitrification.
For the past couple of years, the incidence of avoiding fresh embryo transfers and freezing all the embryos has been increasing. This is mainly due to the increased use of preimplantation genetic screening (PGS) of embryos. Embryos are cultured for 5 or 6 days after egg retrieval till they reach the blastocyst stage. At this point, embryo biopsy is performed (a few cells from the part of the embryo that forms the placenta are removed) and the embryos are then frozen.
We are getting excellent pregnancy rates with elective single embryo transfer of a chromosomally normal blastocyst. Other reasons for freezing all embryos include prevention of ovarian hyperstimulation syndrome, elevation in progesterone level on day of hCG, slow growing embryos that reach blastocyst stage only on day-6 and patient preference. Currently, at InVia Fertility, we are freezing all embryos in almost 40% of fresh IVF cycles, and we expect this number to increase.
A fairly common situation we face is with patients that have only one embryo that remains cryopreserved. For the purposes of this blog, let us assume it is NOT a biopsied embryo. The question I then get asked is, “What should I (we) do with the one frozen embryo?” Should we attempt pregnancy with the one frozen embryo, or do a fresh in vitro fertilization (IVF) cycle?
The answer will vary based on your age, number of children you wish to have and if you want to use preimplantation genetic screening (PGS).
If you have failed a fresh IVF cycle and have one frozen embryo
Historically, the answer used to always be to use the one frozen embryo before proceeding with a fresh IVF cycle. Why freeze the embryo if you are not planning to use it?
However, there are a couple of exceptions.
- If you are 38 years or older and would like to have more than one child. In this situation, it could make sense for you to do another fresh cycle and hopefully freeze a few more embryos as well. If the fresh cycle is successful, you will then have relatively “young” embryos waiting to be used when you are ready to have another baby.
- If you have failed a fresh cycle after transfer of “top quality” embryo(s). The commonest reason IVF fails is because the embryos are chromosomally abnormal. Yes, even embryos that “look” great could be chromosomally abnormal. In this situation, you may want to consider doing another fresh cycle with pre-implantation Genetic Screening (PGS) of the embryos. When the “fresh” embryos are being biopsied, you could also thaw and biopsy the one frozen embryo. This may be more cost-effective rather than doing PGS on the single frozen embryo. The cost of doing PGS on “one” or “up to eight” embryos is the same at InVia.
If you have had a baby with the fresh cycle and have one frozen embryo
In this case, you may want to use it first. However, if you now wish to do PGS, it may make sense to do a fresh cycle and biopsy the “fresh embryos” as well as the one “frozen” embryo.
To see a fertility specialist who can help you decide the best course of action to take with your single frozen embryo, make an appointment at one of InVia's four Chicago area fertility clinics.