Blastocyst culture and transfer in clinical-assisted reproduction

No advantage of fresh blastocyst versus cleavage stage embryo transfer in women under the age of 39: a randomized controlled study

PURPOSE

Is there a difference in implantation and pregnancy rates between embryos transferred electively at cleavage or blastocyst stage in infertile women ≤ 38 years with at least four zygotes on day 1 post retrieval?

METHODS

A randomized clinical trial was conducted in a single tertiary care hospital with a sample size of 194 patients in each arm for a total population of 388 women. Patients less than 39 years of age with more than three fertilized oocytes and less than four previous assisted reproductive technology (ART) attempts were inclusion criteria.

RESULTS

The two groups were similar for age, years of infertility, indication to treatment, basal antimüllerian hormone and FSH, number of previous ART cycles, primary or secondary infertility, type of induction protocol, days of stimulation, total gonadotrophin dose, and estradiol (E2) and progesterone (P) levels at trigger. No statistically significant differences were found in terms of number of retrieved oocytes, inseminated oocytes, fertilization rate, canceled transfers (7.73% in blastocyst and 3.61% in cleavage stage group), and cycles with frozen embryos and/or oocytes. Although a higher number of fertilized oocytes were in the blastocyst stage group (6.18 ± 1.46 vs 5.89 ± 1.54, p = 0.052), a statistically greater number of embryos/randomized cycle were transferred at cleavage stage (1.93 ± 0.371) compared with the number of transferred blastocysts (1.80 ± 0.56), probably due to the number of embryos not reaching blastocyst stage (3.09%). The implantation rate (28.37 vs 25.67%), pregnancy rate per cycle (36.06 vs38.66%), transfer (39.66 vs 40.11%), spontaneous abortions (19.72% vs 12.00%), delivery rate per cycle (27.84 vs 32.99%), and transfer (30.17 vs 34.22%) were not significantly different between the blastocyst and cleavage stage groups. The twin delivery rate was higher in the blastocyst stage group, although not significant (42.59 vs 28.12%). The mean numbers of frozen blastocyst (2.30 ± 1.40 vs 2.02 ± 1.00) and frozen oocytes (7.09 ± 3.55vs 6.79 ± 3.26) were not significantly different between the two groups.

CONCLUSIONS

Fresh blastocyst-stage transfer versus cleavage-stage transfer did not show any significant difference in terms of implantation and pregnancy rate in this selected group of patients. A high twin delivery rate in both groups (35.59%) was registered, and although not significant, they were higher in the blastocyst transfer group (42.59 vs 28.12%). Our conclusion supports considering single embryo transfer (SET) policy, even in cleavage stage in patients younger than 39 years with at least four zygotes.

TRIAL REGISTRATION

ClinicalTrials.gov registration number NCT02639000.

Blastocyst transfer ameliorates live birth rate compared with cleavage-stage embryos transfer in fresh in vitro fertilization or intracytoplasmic sperm injection cycles: reviews and meta-analysis

PURPOSE

Blastocyst transfer has been recommended to raise the implantation rate without affecting the pregnancy rate. The objective of this meta-analysis is to systematically evaluate whether the live birth rate and other pregnancy outcomes can be improved by blastocyst transfer compared with cleavage-stage embryos transfer.

MATERIALS AND METHODS

EMBASE and MEDLINE databases were searched for papers published between March 2004 and March 2013. An extensive range of the electronic databases yielded initially 317 studies from which seven trials met the inclusion criteria for further analysis. Our outcome measures were the live birth rate, clinical pregnancy rate, implantation rate, ongoing pregnancy rate, multiple pregnancy rate, first trimester miscarriage rate and ectopic pregnancy rate. Fixed effects models were chosen to calculate the odds ratio (OR).

RESULTS

Seven trials (n=1446 cases) were finally analyzed. Compared with cleavage-stage embryos transfer, the blastocyst transfer was statistically significantly associated with an increase in clinical pregnancy rate [OR 1.43; 95% confidence interval (CI), 1.15-1.78], implantation rate (OR 1.38; 95% CI, 1.09-1.74) and ongoing pregnancy rate (OR 2.15; 95% CI, 1.57-2.94), and also a reduction in the probability of first trimester miscarriage rate (OR 0.51; 95% CI, 0.30-0.87). The improvement in the live birth rate was also observed (OR 1.77; 95% CI, 1.32-2.37). Moreover, there was no evidence of difference in multiple pregnancy and ectopic pregnancy rates.

CONCLUSION

The available evidences suggest that live birth and other pregnancy outcomes after fresh in vitro fertilization or intracytoplasmic sperm injection (IVF/ICSI) are significantly improved following blastocyst transfer as compared to cleavage-stage embryo transfer.

Clinical outcome of fresh and vitrified-warmed blastocyst and cleavage-stage embryo transfers in ethnic Chinese ART patients

Objectives

This study sought to evaluate the outcome of fresh and vitrified-warmed cleavage-stage and blastocyst-stage embryo transfers in patients undergoing ART treatment within an ethnic Chinese population.

Study design

We compared the clinical results of embryo transfer on the 3rd (cleavage stage) or 5th (blastocyst stage) day after oocyte retrieval, including clinical pregnancy rates, implantation rates and multiple pregnancy rates.

Results

Our data showed that blastocyst transfer on day 5 did not significantly increase clinical pregnancy rate (41.07% vs 47.08%, p>0.05) and implantation rate (31.8% vs 31.2%, p>0.05) in patients under 35 years of age, in comparison with day 3 cleavage stage embryo transfer. In patients older than 35 years of age, the clinical pregnancy rate after blastocyst transfer was slightly decreased compared with cleavage stage embryo transfer (33.33% vs 42.31%, p>0.05). Unexpectedly, It was found that vitrified-warmed blastocyst transfer resulted in significantly higher clinical pregnancy rate (56.8%) and implantation rate (47%) compared with fresh blastocyst transfer in controlled stimulation cycles (41.07% and 31.8%, respectively). For patients under 35 years of age, the cumulative clinical pregnancy rate combining fresh and vitrified-warmed blastocyst transfer cycles were significantly higher compared to just cleavage-stage embryo transfer (70.1% versus 51.8%, p<0.05). However, the cumulative multiple pregnancy rates showed no significant difference between the two groups.

Conclusions

In an ethnic Chinese patient population, fresh blastocyst transfer does not significantly increase clinical pregnancy rate. However, subsequent vitrified-warmed blastocyst transfer in a non-controlled ovarian hyperstimulation cycle dramatically improves clinical outcomes. Therefore, blastocyst culture in tandem with vitrified-warmed blastocyst transfer is recommended as a favourable and promising protocol in human ART treatment, particularly for ethnic Chinese patients.

Supernumerary blastocyst cryopreservation: a key prognostic indicator for patients opting for an elective single blastocyst transfer (eSBT)

OBJECTIVE

To determine if patients, less than 40 years of age with or without day 5 cryopreservation (d5 cryo), compromise their pregnancy rate (PR) by choosing an eSBT.

DESIGN

Retrospective analysis

SETTING

University IVF center

PATIENTS

2,203 non-donor fresh IVF cycles in women <40 years of age from January 2004 to January 2010.

INTERVENTIONS

None

MAIN OUTCOME MEASURE(S)

Eggs retrieved, Embryos cryopreserved, Implantation Rates, Clinical Pregnancy Rates, Live Birth Rates, Spontaneous Abortion Rates

RESULTS

Pregnancy outcomes in women <40 years with or without d5 cryo were compared according to whether patients underwent an eSBT versus a 2BT in non-donor fresh IVF cycles. Overall, eSBT was associated with elimination of twinning while maintaining a high clinical pregnancy rate in both groups with d5 cryo (75 % eSBT versus 72 % 2BT) and groups without d5 cryo (48 % eSBT versus 56 % 2BT).

CONCLUSIONS

In this study, patients <40 years of age have eliminated twinning by electively choosing to transfer a single blastocyst without compromising their PR if embryos are available for d5 cryo, and suffer only a non-statistically significant drop in their PR if there are no embryos available for d5 cryo in exchange for the benefit of eliminating the obstetrical risk of twinning.

Reduction in exposure of human embryos outside the incubator enhances embryo quality and blastulation rate

Embryo quality is strongly dependent on the in-vitro culture environment. Conventionally, IVF/intracytoplasmic sperm injection (ICSI) embryos are examined microscopically every morning (from day 1 to day 6) to assess fertilization, cleavage and embryo quality. Consequently, the frequent exposure to non-optimal conditions outside the incubator may adversely affect embryonic viability and quality. Hence, this study investigated whether reduction of observation frequency outside the incubator can enhance blastocyst formation rate. A total of 285 IVF/ICSI cycles were divided into two groups. Embryos in the control group (103 cycles) were assessed out-of-incubator every day after insemination (day 1 to day 6; six times). In the experimental group (182 cycles), embryos were assessed four times, on days 1, 3, 5 and 6. The total blastocyst formation rate, day-5 blastocyst formation rate, proportion of good blastocysts and number of cryopreserved blastocysts per patient were significantly lower for the control group compared with the experimental group (42.5%, 31.4%, 50.7%, 1.72+/-1.55 versus 52.6%, 40.7%, 60.1%, 2.64+/-2.59, respectively, P<0.05); although there were no significant differences in the proportions of good embryos on day 3, blastocyst formation rate on day 6, clinical pregnancy rate and implantation rate. Hence, reduction of the observation frequency of embryos outside the incubator can enhance embryo quality and blastocyst formation rate.