There is a breakthrough for IVF treatment with frozen thawed embryos which may revolutionize clinical practices. Many patients question the stability and efficacy of using long frozen eggs. More and more, patients are freezing and transferring extra embryos. Is it safe to use them later? How much later?
A new study shows that miscarriage is less likely to occur after the transfer of fresh embryos compared to thawed embryos. However, the age of the embryo at the time of freezing influences its viability.

Y.A Wang and colleagues analyzed over 52,000 pregnancies from Australia and New Zealand Assisted Reproduction Database between 2004 and 2008. They reviewed the woman’s age and obstetric history and review the risk of miscarriage. They found that transfer of fresh embryos is associated with fewer miscarriages.

The miscarriage rate for almost 19%. Young women were shown to be almost three times less likely to miscarry than women over 40 years of age. Women who had elective single embryo transfer were also less likely to miscarry than when two embryos were transferred. Embryos frozen earlier in the fertilization process were less likely to miscarry, those embryos frozen prior to the blastocyst stage.

The authors of the new research suggested that a practice model of transferring fresh blastocysts and freezing of cleavage-stage embryos would reduce the number of miscarriages after IVF.

“It is interesting that miscarriage rates of frozen blastocysts were higher in the Australian study, particularly since it is well known that blastocysts have a lower frequency of chromosomal anomalies than cleaved embryos,” said Dr. Jacques Cohen, senior editor of Reproductive BioMedicine Online. The researchers acknowledged this in their findings and said that further studies would need to be performed.

Source: http://www.conceivingconcepts.com/news/treatment/new-best-practice-for-ivf-may-reduce-miscarriage