Women are not really sure about frozen embryos’ ability to result in pregnancy. Ironically, the success of Frozen Embryo Transfer has dramatically improved over the last few years. In the days gone by, the chance of women getting pregnant through the use of frozen embryos seemed to be on the lower side compared to that from the transfer of fresh embryos. Recent data related to this suggests that this is no longer the case.
Reasons behind the low success rate of frozen embryo transfer in the past
Previously during the frozen embryo transfer process, the embryos which had to get frozen were the ones that did not get chosen for the fresh embryo transfer initially. The reason being that the embryologist had gone ahead to choose the best possible embryos for getting them transferred initially. As far as the fresh embryo transfer is concerned, quality of embryo has got a major effect on the chance of a woman getting pregnant. On the other hand, if quality of embryos frozen is not good, the rate of survival after it gets thawed along with the rate of pregnancy would be on the lower side.
The second important reason is the amount of embryos that got transferred. Let us consider a couple who produce four very good quality embryos. Two of them are transferred during fresh In Vitro Fertilization Process and the remaining two are frozen. This leads to pregnancy and the woman gives birth to a baby. Later on, the couple once again decides to go for pregnancy by using the frozen embryos. Though only one embryo survives after getting thawed. The frozen embryo transfer is that of a single embryo. The success rate of a frozen embryo transfer through a single embryo is always going to be on the lower side than what it will be when multiple embryo transfer is involved.
Finally the method of freezing embryos has seen a sea change quite a number of years ago. Nowadays the freezing of embryos takes place by a fast method, known as vitrification. This process has got a much better survival rate when embryos get thawed along with good rates of pregnancy when those particular embryos are transferred in a much better manner.
Studies about high success rate of frozen embryo transfer
There have been studies performed in women, who have had quite a vigorous stimulation of their ovaries and were considered to be at high risk for Ovarian Hyperstimulation Syndrome. The physicians took the decision of skipping the process of embryo transfer and instead go ahead to freeze all the embryos for use at a later stage.
This tends to significantly decrease the risk of having serious Ovarian Hyperstimulation Syndrome along with decrease in complications. Other cases involved, physicians deciding to move on with a fresh embryo transfer depite the risk of Ovarian Hyperstimulation Syndrome. In both the scenarios the couples have quite a large number of embryos and the embryos selected for transfer were the best embryos.
The studies have shown no difference in the rates of pregnancy between fresh or frozen embryos or for that matter higher rate of pregnancy with frozen embryos. In case you have a concern or query you can always consult an expert & get answers to your questions!