IVF with frozen eggs produced a live birth rate of 43% in 2013, while the live birth rate for traditional IVF was 50%.
Traditionally, fresh oocytes that have been donated for in vitro fertilization (IVF) have been used for fertilization once. The embryos created can be transferred immediately or in the uterus (cryopreserved) are frozen for use at a later date.
In recent years, however, oocyte cryopreservation has grown in popularity, in which a woman’s eggs are removed, frozen and stored. When a woman decides she is ready to become pregnant, the eggs can be thawed and fertilized by standard IVF procedure.
A number of studies have suggested success rates of IVF with frozen eggs are comparable to those of IVF using fresh eggs. As such, the American Society for Reproductive Medicine (ASRM) and the Society for Assisted Reproductive Technology (SART) published a common approach in 2013 stating that oocyte cryopreservation “no longer be considered experimental.”
However, before universal oocyte cryopreservation can be recommended, the ASRM-SART guideline called for “more extended specific clinical data on the safety and efficacy” of the technique.
egg donation banks still frozen, some fertility clinics in the US have introduced, encouraged by research indicating IVF using oocyte cryopreservation is as successful as traditional IVF.
In the latter study, Dr. Vitaly A. Kushnir, the Center for Human Reproduction in New York, New York, and colleagues set out to assess the results of IVF oocyte cryopreservation using in routine clinical practice – something that the team says that has not been previously investigated.
7% lower live birth with cryopreservation of oocytes
The researchers analyzed data from 2013 for 380 fertility centers in the US .. These centers perform 92% of all IVF cycles in the country that year, according to the authors.
The team identified 11,148 cycles of oocyte donation, of which 2,227 (20%) involved the use of cryopreserved oocytes, and rates of living of each technique of IVF births were compared.
Basic facts about infertility
- In the US, 1 in 8 couples have trouble getting pregnant or maintaining a pregnancy
- About 7.4 million women in the US They have never received infertility services in his life
- Less than 3% of infertility cases in the US They are treated with assisted reproductive techniques such as in vitro fertilization; around 85-90% of cases are treated with surgical procedures or medications.
The results of the analysis revealed that the rates of live births with the use of cryopreservation of oocytes in each IVF cycle were completed less than 43%, compared to 50% using fresh oocytes.
For each embryo transfer, the live birth rates were 47% with the use of frozen oocytes and 56% using fresh oocytes.
While researchers are not able to identify the exact reasons for rates lower birth live with the use of oocyte cryopreservation, they hypothesize that can be down to the reduced number of eggs used for this procedure FIV.
“In traditional therapy egg donor (fresh eggs), the recipient receives all donor eggs made (typically 15-25),” James Toner, president of SART, told The Washington Post . “When the frozen eggs are used, they provide only a batch of 6-8 eggs. This has a big effect on the results!”
In addition, Dr. Kushnir and his colleagues say it is possible that the quality of oocytes could be compromised during the process of freezing and thawing.
They stress , however, that their research should be “cautious” noting that they did not take into account possible confounding factors such as age of the donor and recipient egg and diagnosis of infertility.
In another part of Medical News Today , a new study published in the Journal of Endocrinology suggests that oocyte retrieval earlier in the process of in vitro fertilization can improve rates success for older women .