Embryonic, genetic and clinical outcomes of fresh versus vitrified oocyte: A retrospective cohort study

Objective:To compare embryonic development,ploidy status and clinical outcomes between fresh and frozen-thawed oocytes.Methods:This retrospective cohort study evaluated 83 fertilization cycles including both fresh and frozen oocytes from 79 patients at the HP Fertility Center of Hai Phong International Hospital of Obstetrics and Pediatrics in Vietnam.The patient underwent several ovarian stimulation cycles to accumulate a certain number of oocytes that would be vitrified.In the last oocyte retrieval,all patient’s oocytes including both frozen and fresh would be fertilized.The outcomes included the rates of oocyte survival,cleavage embryo,blastocyst,ploidy status,pregnancy,biochemical pregnancy and clinical pregnancy.Results:The oocyte survival rate after thawing was 96.5%.No statistically significant difference was found when comparing fresh and frozen oocytes regarding fertilization rate(78.1%vs.75.5%,P=0.461),usable cleavage embryo rate(86.9%vs.87.2%,P=0.916)but usable blastocyst rate was found higher statistically in the frozen oocyte group(44.4%vs.54.0%,P=0.049).The percentages of euploid,aneuploid and mosaic embryos between the fresh group and the vitrified group had no significant differences(33.8%vs.31.6%,P=0.682;51.0%vs.54.2%,P=0.569;15.2%vs.12.4%,P=0.787;respectively).The rates of pregnancy,biochemical pregnancy and clinical pregnancy had no statistical difference(68.8%vs.64.8%,P=0.764;12.5%vs.3.6%,P=0.258;37.5%vs.46.4%,P=0.565).17 Mature oocytes are the minimum to have at least one euploid embryo.Conclusions:Oocyte vitrification does not affect embryonic,genetic and clinical results.The number of mature oocytes should be considered for fertilization in some cases.

First Babies from Cryopreserved Oocytes in Hungary

Objective To evaluate the value of oocyte cryopreservation （CP） in our clinical ICSI program. Methods Freezing procedure with medium containing 1.5 mol/L propanediol （PrOH） ＋ 0. 3 mol/L succrose and traditional slow-freezingprotocol were used. Thawed oocytes were fertilized with ICSI （4-6 h after thawing）, and fertilization was assessed 12-16 h later. Laser assisted hatching was performed on all transferred embryos and embryo transfer was carried out 48-72 h after ICSI. Results Eighty-five eggs were thawed and survival rate of 75.3% （64/85） was obtained. Sixty-four oocytes were inseminated with ICSI, 47fertilized （47/64; 73.4%） and a cleavage rate of 85% （40/47） was obtained. Embryo transfers were performed in 18 patients, and 4 （19%） resulted in clinical pregnancies. One of the pregnancies encountered first trimester abortion. Implantation rate were 17.2% （5/29） per embryo and 5.8% （5/85） per egg thawed. In all cases, chorion biopsy was performed resulting 46 XY kariotype. Conclusion Our results provide further evidence of that although egg freezing cannot currently claim to be a routine procedure in human IVF,, there will certainly be a place for oocyte CP in reproductive medicine in the future.

An efficient method for the sanitary vitrification of bovine oocytes in straws

Background：At present,vitrification has been widely applied to humans,mice and farm animals.To improve the efficiency of vitrification in straw,bovine oocytes were used to test a new two-step vitrification method in this study.Results：When in vitro matured oocytes were exposed to 20%ethylene glycol（EG20） for 5 min and 40%ethylene glycol（EG40） for 30 s,followed by treatment with 30%glycerol（Gly30）,Gly40 or Gly50,a volume expansion was observed in Gly30 and Gly40 but not Gly50.This indicates that the intracellular osmotic pressure after a 30 s differs between EG40 and ranged between Gly40（approximately 5.6 mol/L） and Gly50（approximately 7.0 mol/L）.Since oocytes are in EG40 just for only a short period of time（30 s） and at a lower temperature（4℃）,we hypothesize that the main function of this step in to induce dehydration.Based on these results,we omitted the EG40 step,before oocytes were pretreated in EG20 for 5 min,exposed to pre-cooled（4℃） Gly50,for 30 s,and then dipped into liquid nitrogen.After warming,81.1%of the oocytes survived,and the surviving oocytes developed into cleavage stage embryos（63.5%） or blastocysts（20.0%） after parthenogenetic activation.Conclusions：These results demonstrate that in a two-step vitrification procedure,the permeability effect in the second step is not necessary.It is possible that the second step is only required to provide adequate osmotic pressure to condense the intracellular concentration of CPAs to a level required for successful vitrification.

Female Fertility： Is it Safe to Freeze.

Objective： To evaluate the safety and risk of cryopreservation in female fertility preservation. Data sources： The data analyzed in this review were the English articles from 1980 to 2013 from journal databases, primarily PubMed and Google scholar. The criteria used in the literature search show as tbllowing： （ 1 ） human; embryo; cryopreservation/freezing/vitrification, （2） human; oocyte/immature oocyte; cryopreservation/freezing/vitrification, （3） human; ovarian tissue transplantation; cryopreservation/ freezing/vitrification, （4） human; aneuploidy/DNA damage/epigenetic; cryopreservation/freezing/vitrification, and （5） human; fertility preservation; maternal age. Study selection： The risk ratios based on survival rate, maturation rate, fertilization rate, cleavage rate, implantation rate. pregnancy rate. and clinical risk rate were acquired from relevant meta-analysis studies. These studies included randomized controlled trials or studies with one of tile primary outcome measures covering cryopreservation of human mature oocytes, embryos, and ovarian tissues within the last 7 years （from 2006 to 2013. since the pregnancy rates of oocyte vitrification were significantly increased due to the improved techniques）. The data involving immature oocyte cryopreservation obtained from individual studies was also reviewed by the at, thors. Results： Vitrifications of mature oocytes and embryos obtained better clinical outcomes and did not increase the risks of DNA damage, spindle configuration, embryonic aneuploidy, and genomic imprinting as compared with fresh and slow-freezing procedures, respectively. Conclusions： Both embryo and oocyte vitrifications are safe applications in female fertility preservation.

Chinese expert consensus on clinical practice of female fertility preservation

Many female fertility preservation-related technologies have recently been developed in response to increasing demand for such treatments. To establish standard practices of female fertility preservation in China, the Chinese Maternal and Child Health Association Affiliated Fertility Preservation Professional Committee assembled specialists to construct a consensus, referring to the current clinical guidelines of some countries combined with clinical practice and expert opinions. The consensus includes two parts: (1) indications for female fertility preservation and related techniques, in which we sought to be inclusive regarding the indications for fertility preservation;and (2) practical guidance for the clinical application of the female fertility preservation technologies.

Fertility preservation for female patients with childhood and adolescent cancer

With the significant cancer treatment in the past decades,>85%of children with cancer now survives into adulthood,and fertility preservation has become an important quality-of-life technology for them.1 Cancer treatment may include surgery,chemotherapy,radiotherapy,and/or hematopoietic stem cell transplantation(HSCT).2 Except for non-pelvic surgery,these treatments may affect ovarian function and consequently cause varying degrees of gonadal toxicity.3 Patients cured by anti-cancer treatment have a very high risk of premature ovarian insufficiency(POI).

Fertility Preservation in Cancer Patients

Traditional radiotherapy and chemotherapy often cause irreversible damage to the fertility and endocrine function of cancer patients.The current methods of fertility preservation include freezing the sperms of adult and adolescent males after puberty;freezing the embryos,oocytes,and ovarian tissue of females;and drug intervention and fertility preservation surgery.This article reviews fertility preservation in cancer patients with respect to current methods,indications,and some more recently developed methods that remain under investigation.