For some time now our experience has shown us that when we do all-freeze cycles and only tranfer embyos in frozen embryo cycles we get better results. This phenomenon occurs whether PGS is performed to help us select chromosomally normal embryos or in non-PGS cycles when we select embryos by morphology.
However in contrast to our experience, results from two Asian studies suggest that frozen embryos may be comparable to fresh ones for women having in vitro fertilization (IVF), researchers reported. In one study of 2,157 ovulatory women with infertility in China, the live-birth rate did not differ significantly between the frozen-embryo group and the fresh-embryo group (48.7% and 50.2%, respectively). In a Vietnamese study, rates of live births after the first transfer were comparable between groups: 33.8% with frozen embryos and 31.5% with fresh embryos.
Both studies were published online in the New England Journal of Medicine.
Some research has shown that frozen-embryo transfer results in a higher live-birth rate than fresh-embryo transfer in anovulatory women with polycystic ovary syndrome (PCOS), as it may provide a more physiologic uterine environment for embryo implantation. The researchers acknowledged several limitations, including potential bias due to lack of blinding and a withdrawal and protocol deviation rate that was higher than 15%. Additionally, the embryos were transferred at cleavage stage in order to minimize the risk of arrested embryo development leading to no embryo transfer.
Our transfers are almost all at the blastocyst stage and many have has PGS to enhance the selection of the embryo. So although these studies show no significant difference in outcome between fresh and primary frozen transfers, their methods are so different than ours that you really cannot draw any conclusions on the benefts of fresh vs. frozen embryo transfers when using blastocysts.
In fact, at Reproductive Partners we have developed and refined an optimized protocol of tests and procedures designed to maximize your chance of a healthy single live birth. This makes IVF safer for you while decreasing the chance of prematurity, and certain genetic diseases or chromosomal abnormalities in your baby. It includes frozen embryo transfer and is called, “Single Transfer, Safer Pregnancy, Healthier Baby.”