Slow freezing and vitrification of mouse morula and early blastocysts

Purpose

To assess the relative success of morula and early blastocyst slow freezing and vitrification in regards to survival and implantation rates utilising protocols which could be clinically implemented as a viable alternative to expanded blastocyst stage freezing.

Methods

Mouse morula and early blastocysts were either slow frozen/thawed or vitrified/warmed. Their subsequent survival, blastocyst development and blastocyst cell number and allocation to either the inner cell mass, trophectoderm or epiblast was assessed. In addition blastocysts were also transferred to pseudopregnant recipients and implantation and fetal development was determined.

Results

Vitrification of both morula and early blastocysts resulted in significantly higher rates of survival and blastocyst development compared to slow freezing. In addition slow frozen early blastocysts had significantly reduced blastocyst cell number compared to control however vitrified morula and early blasocyts and slow frozen morula had equivocal blastocyst cell numbers. Transfer of blastocysts from both methods of cryopreservation resulted in similar implantation rates however the placentas created from slow frozen early blastocysts were significantly lighter than control (95.5 g ± 5.4 vs. 122.0 g ± 4.2 respectively).

Conclusions

Vitrification resulted in significantly higher rates of morula and early blastocyst survival and blastocyst development compared to slow freezing. In addition this study has validated the use of a closed DMSO free vitrification protocol which could then be investigated for use in the clinical setting as an alternative to expanded blastocyst freezing.     

Injection of embryo culture supernatant to the endometrial cavity does not affect outcomes in IVF/ICSI or oocyte donation cycles: a randomized clinical trial

Objective

To evaluate whether intrauterine injection of embryo culture supernatant before embryo transfer has any impact on pregnancy and implantation rates.

Study design

A total of 400 cycles, of which 200 IVF/ICSI and 200 oocyte donor (OD), were randomly assigned to have their uterine cavity injected (group I) or not (group II). Primary endpoints to be studied were pregnancy and implantation rates.

Results

Clinical pregnancy rate per transfer (47.87%, 90/188 versus 48.45%, 94/194) based on transvaginal scan findings at 7 weeks of gestation and implantation rate (25.6% versus 26.5%) were similar in the two groups. The day of embryo transfer, day 3 or day 5, did not affect the final outcome.

Conclusion

Injection of embryo culture supernatant into the uterine cavity, 30 min before the embryo transfer on either day 3 or 5, neither improves nor adversely affects the pregnancy rate in IVF/ICSI or oocyte donation cycles.     

Retrospective clinical analysis of two artificial shrinkage methods applied prior to blastocyst vitrification on the outcome of frozen embryo transfer

Purpose

Vitrification significantly improves the rates of blastocyst survival and clinical pregnancy following frozen embryo transfer (FET). However, ice crystal formation during the freezing process reduces the blastocyst survival rate. Artificial shrinkage (AS) prior to blastocyst vitrification decreases the formation of ice crystals, increasing the blastocyst survival rate. The aim of this study was to identify an efficient AS method to improve blastocyst survival rates following vitrification.

Method

Use of the 29-gauge needle AS and Laser pulse AS methods prior to vitrification was compared in terms of the impacts on the rates of blastocyst survival in FET cycles, blastocyst hatching, clinical pregnancy after transfer, embryo implantation, abortion, gestational duration and birth weight.

Result

In total, 438 blastocysts in 219 cycles were thawed, resulting in survival of 407 (92.9 %). Of these, 213 cycles were transferred, resulting in 129 clinical pregnancies (60.6 %) and 140 successful births. There were no differences between the two methods in the rates of blastocyst survival, clinical pregnancy, embryo implantation and abortion. However, the 29-gauge needle AS group was associated with a significantly lower blastocyst hatching rate (83.6 % vs. 91.2 %), shorter average gestational duration (37.36 ± 2.34 vs. 38.06 ± 1.76), and higher premature birth rate (40.00 % vs. 21.15 %) compared with Laser pulse AS group.

Conclusion

No significant differences in the effectiveness of the two methods applied prior to blastocyst vitrification were observed before birth, while after birth, a significantly improved clinical outcome was obtained with laser pulse AS indicating that this is a more effective pre-processing method for blastocyst vitrification.     

Live birth rate from euploid blastocysts is not associated with infertility etiology or oocyte source following frozen-thawed embryo transfer (FET): analysis of 4148 cycles reported to SART CORS

PurposeTo investigate whether live birth rates from euploid blastocyst frozen-thawed embryo transfer (FET) cycles are associated with infertility diagnosis or oocyte source.DesignRetrospective analysis of FET cycles reported to SART CORS in 2014.MethodsData from fresh IVF cycles with preimplantation genetic testing for aneuploidy (PGT-A), linked to the first FET cycles, were collected from the 2014 SART CORS database for autologous and donor oocyte cycles. Inclusion criteria were patients undergoing FET with euploid embryos (n = 4148). Demographic data including age, BMI, prior fertility, and etiology of infertility were collected from the retrieval cycle and analyzed. Patients with uterine anomalies, preimplantation genetic testing-mutation (PGT-M) for genetic diseases, gender selection, HLA determination, or systemic and immunologic disorders were excluded. The primary outcome measure was live birth (LB) rate. Potential confounders such as age, prior fertility, and maximum baseline FSH values were analyzed with regression models as indicated.ResultsThough age, maximum baseline FSH, and infertility diagnosis were significantly different, LB was similar between patients undergoing autologous or donor oocyte FET cycles. Etiology of infertility was not significantly associated with LB in autologous cycles (p = 0.95). Potential confounders such as maternal age, prior fertility, and maximum baseline FSH were not associated with outcomes; however, maternal BMI was inversely related to LB in autologous cycles, with an odds ratio of 0.97 (95% CI: 0.96–0.98 (rho = − 0.08, p < 0.01)).ConclusionsAfter controlling for confounding variables, a euploid embryo derived from a donor or autologous oocyte results in similar LB in women with different infertility diagnoses.