The influence of delayed blastocyst formation on the outcome of frozen-thawed blastocyst transfer: a systematic review and meta-analysis (original) (raw)
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Human reproduction (Oxford, England), 2018
The aim of this study was to evaluate the live birth rate (LBR) after frozen-thawed Day 5 (D5) and Day 6 (D6) blastocyst transfers. LBR following frozen-thawed blastocyst transfer is significantly lower with D6 than with D5 blastocyst regardless of embryo quality. During fresh embryo transfer cycles, pregnancy rates (PR) are significantly higher when transferring blastocysts expanded on D5 compared with slow developing blastocysts (D6). In programmed thawed blastocyst transfer (TBT) cycles, the same clinical outcomes should be expected when transferring D5 or D6 blastocysts because of endometrial/embryonic synchronization due to hormonal priming of endometrial receptivity. However, the impact of delayed blastocyst expansion at D6 on clinical outcomes remains unclear. Some reports have shown higher PRs after D5 TBT compared with those of D6, while others have shown equivalent TBT outcomes after D5 and D6 cryopreserved blastocysts transfers. This retrospective cohort follow-up study i...
Delayed blastocyst development does not influence the outcome of frozen-thawed transfer cycles
BJOG: An International Journal of Obstetrics & Gynaecology, 2011
Objective To compare the outcome of transfer of thawed blastocysts frozen on either day 5 or day 6 after in vitro fertilisation. Design Cohort observational study. Setting Tertiary assisted conception unit in London, UK. Population Six hundred and forty-two consecutive nondonor programmed thawed blastocyst transfer (TBT) cycles. Methods High-grade blastocysts were frozen on day 5 (n = 314) or day 6 (n = 328) after fertilisation using a slow-freezing protocol. Endometrial preparation was performed using estradiol valerate. Progesterone supplementation was commenced when the endometrial thickness had reached 7 mm or more. Frozen blastocysts were thawed on day 6 of progesterone supplementation and assessed immediately after thawing for survival, and after 3-4 hours for blastocoele re-expansion. Main outcome measures Thawed blastocyst survival and re-expansion rates, and pregnancy and live birth rates, per TBT. Results Thawed blastocyst survival and re-expansion rates were comparable between the day 5 and day 6 groups (87% versus 87%, P = 0.50 and 73% versus 71%, P = 0.35, respectively). The live birth rate was similar between the two groups (29% versus 28.5%, P = 0.93, respectively). After adjusting for confounding variables, the odds ratio (OR) of a live birth in cycles in which the thawed blastocysts were frozen on day 6 compared with day 5 was 1.23 [95% confidence interval (CI), 0.81-1.86, P = 0.34]. Conclusion The pregnancy potential of high-grade blastocysts frozen on day 5 and day 6 after in vitro fertilisation and replaced in programmed TBT cycles is comparable.
Comparison of perinatal outcomes following fresh and frozen-thawed blastocyst transfer
International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics, 2016
To investigate the effect of ovarian stimulation on endometrial receptivity by comparing singleton pregnancy and perinatal outcomes following fresh or frozen-thawed blastocyst transfers. A retrospective cohort study enrolled patients undergoing fresh or frozen-thawed blastocyst transfers that resulted in live deliveries between January 1, 2010 and September 30, 2013 at a single academic center. Implantation, clinical pregnancy, spontaneous abortion, and live delivery rates were calculated. The incidence of term delivery, preterm delivery, low birth weight, term low birth weight, and very low birth weight were also recorded. To detect a 10% difference in the implantation rate, a minimum sample size of at least 415 transfer cycles in each group was estimated. The study included data from 918 fresh and 1273 frozen-thawed cycles. Patients in both groups were of similar age and there was no difference in the grading of blastocysts. No differences were observed in the implantation (37.3% ...
Journal of Assisted Reproduction and Genetics, 2004
Purpose : To compare the effects of two different blastocyst thawing protocols on implantation, pregnancy, and live birth rates. Methods : Ninety four consecutive frozen-thawed blastocyst transfers from 1996 to 2002 were retrospectively analyzed. Blastocysts were cryopreserved using Menezo's two-step slowfreezing protocol. Frozen blastocysts were thawed for transfer according to Menezo's stepwise or two-step protocol. Immediately after thawing, assisted hatching was performed and all embryos were cultured for 3 to 5 h before transfer. Only viable embryos were selected for transfer. Results : Implantation, pregnancy (determined by the presence of fetal cardiac activity), and live birth rates were significantly higher with two-step (25, 45.7, and 42.9%) than with stepwise thawing protocol (9.2, 18.6, and 16.9%, P < 0.01). The percentage of gestational sacs resulting in live babies was higher with two-step thawing (76.6%) than with stepwise thawing (50%, P = 0.04). Conclusions : We conclude that the two-step thawing protocol offers advantages over the stepwise method. The two-step thawing protocol dramatically increased embryo implantation potential, resulting in higher pregnancy rate, and subsequent live birth rate, after frozen blastocyst transfer.
Fertility and sterility, 2016
To evaluate factors associated with cryopreserved blastocyst transfer birth outcomes, including age, expansion time, cryopreservation protocol, cryodamage, and number of embryos transferred. Retrospective cohort study. Private infertility practice. Cryopreserved blastocyst transfer patients from January 2003 to April 2012. None. Birth per transfer and children per embryo. Overall live birth per transfer was 32%, with 17% twin births and 0.3% triplets. Live birth per transfer was significantly higher for vitrification compared with slow-freeze (day 5 cryopreservation: 47% vs. 35%; day 6 cryopreservation: 46% vs. 24%), as was live born children per transferred embryo (39% vs. 29% for day 5; 36% vs. 18% for day 6). Birth rates declined only slightly with increasing age at cryopreservation through 37 years, followed by an increasingly rapid decline in success with increasing age thereafter. Live birth rates declined rapidly (49%-18% for vitrification and 37%-10% for slow-freeze) as the ...
Frozen-thawed embryo transfer cycles: clinical outcomes of single and double blastocyst transfers
Journal of Assisted Reproduction and Genetics, 2011
Purpose To evaluate clinical outcomes of frozen-thawed embryo transfer cycles when one or two blastocysts are transferred. Methods Retrospective chart review Results Two hundred forty-three frozen blastocyst transfer (FBT) cycles were analyzed. Clinical pregnancy rate (50.4% vs. 34.7%), live birth rate (45.8% vs. 30.6%), and twin live birth rate (19.3% vs. 0) were significantly higher in the double versus single FBT group, respectively (p<0.05). Prior fresh cycle success with same-cohort embryos did not predict outcome of FBT cycle. When the fresh cycle was unsuccessful, there still was a significant increase in twinning when two frozen-thawed blastocysts were transferred. Conclusions Transferring two blastocysts during an FBT cycle resulted in higher live birth and twin live birth rates. Single FBT provided acceptable pregnancy rates for couples seeking to avoid a multiple pregnancy or for those having a single blastocyst stored. Interestingly, the outcome of fresh cycle with same-cohort embryos did not influence the outcome of frozen-thawed cycle.
Journal of Clinical Medicine
The frozen embryo transfer (FET) technique has been progressively used more worldwide due to improved culture conditions, as well as enhanced survival rates after vitrification. However, little is known about the effect of the post-thaw blastocyst culture duration prior to transfer on live birth rate in FET cycles. In this retrospective observational study, we evaluated the influence of two distinct post-thaw blastocyst culture spans (2–4 h versus 20–22 h) on clinical pregnancy and live birth rate. A total of n = 1927 frozen–warmed cycles were included in the analysis. Among those, n = 885 warmed blastocysts were cultured for 2–4 h, and n = 1029 were kept in culture for 20–22 h prior to transfer; the remaining blastocysts did not survive the warming protocol. We observed no significant differences in live birth and clinical pregnancy rates between the two groups. The blastocyst morphological evaluation at transfer improved following the longer culture time. No differences between th...
The European Research Journal, 2023
Objectives: Our study examined the effects of the trophectoderm biopsy (TB) day and the presence of necrotic foci (NF) or separate blastomeres (SB) within euploid embryos on in vitro fertilization (IVF) pregnancy outcomes. Methods: This retrospective cohort study was conducted from January 2017 to September 2021 at Memorial Sisli Hospital, Istanbul, Turkey. The study comprised a total of 2758 frozen-thawed euploid embryo transfer cycles. After thawing, blastocysts were graded using Gardner's classification Top-Quality (TQ), Good-Quality (GQ), Moderate-Quality (MQ), Poor-Quality (PQ) and further divided into groups according to the presence of NF and/or SB and evaluated for pregnancy outcomes. Results: There were significant correlations between pregnancy outcomes and the degree of blastocoele expansion, as well as the presence of NF or SB in the euploid embryo. Ongoing pregnancy rates were lower in the group with NF in the inner cell mass (ICM) or trophectoderm (TE) than in the group without NF. The presence of SB decreased the rates of ongoing pregnancy and increased the rates of miscarriage. Embryos with expansion grades ≤ 3 had lower rates of ongoing pregnancy and higher rates of miscarriage compared to embryos with expansion grades > 3. TQ and GQ embryos had a higher rate of ongoing pregnancy and a lower rate of miscarriage than MQ and PQ embryos. Conclusions: When selecting the embryo to be transferred to a patient, careful consideration should be given to the morphological grade of the embryo as well as whether or not it contains NF and SB.
Int J Fertil Steril, Vol 18, No 2, April-June , 2024
Background: There is a definite shift in assisted reproductive centres from cleavage-stage embryo transfer (ET) to blastocyst transfer that is attributed to improvements in laboratory environments and advances in the development of embryo culture media. The aim of the study was to investigate the reproductive outcomes of thawed cleavage-stage ET versus blastocysts derived from an extended culture of these embryos. Materials and Methods: This open-label, randomised, parallel group clinical trial study enrolled 182 women aged ≤37 years who underwent frozen-thawed ET from November 2015 to June 2020 at Royan Institute Research Centre, Tehran, Iran. The women were randomly assigned to either the thawed cleavage ET group (n=110) or the post-thaw extended culture blastocysts group (n=72). The primary outcome measure was the clinical pregnancy rate. Secondary outcome measures were implantation rate, live birth rate (LBR), and miscarriage rate. A P<0.05 indicated statistical significance. Results: There were no significant differences between the two groups in terms of demographic characteristics. Both the mean numbers of embryos transferred and good quality embryos transferred were significantly lower in the postthaw extended culture blastocysts group compared to thawed cleavage-stage ET cycles. However, the post-thaw extended culture blastocysts group had higher clinical pregnancy (56.94 vs. 40.91%, P=0.034), implantation (34.43 vs. 19.84%, P=0.001) and live birth (49.3 vs. 33.63%, P=0.036) rates compared to the thawed cleavage-stage ET group. Miscarriage and multiple gestations rates were comparable between the groups. Conclusion: These results allow us to take a position in favour of post-thaw extended culture blastocysts; thus, it is important to improve the post-thawing extended culture technique (registration number: NCT02681029).
Fertility and Sterility, 2005
To evaluate the effect of degenerated (lysed) blastomere removal on implantation and pregnancy rates in cleavage-stage cryo-embryo transfer (ET) cycles. Design: Randomized clinical trial. Setting: Private reproductive medical center. Patient(s): A total of 88 patients who received frozen-thawed ET, divided into two groups. Intervention(s): Embryo freezing and thawing; opening of the zona pellucida and removal of cryodamaged blastomeres (in the study group), followed by same-day ET. Main Outcome Measure(s): Extent of survival of cleavage-stage embryos after the freeze-thaw procedure; embryo implantation and clinical pregnancies. Result(s): Oocyte number per patient, fertilization rate, embryo development rate (and quality), and freezing rates were similar in the two groups in the fresh cycle. In the control group, a total of 55 embryos (25%) of the 217 thawed remained fully intact, and 53 (26%) of the 207 in the study group remained intact. The average number of embryos transferred per group was similar (control, 3.4 Ϯ 0.9; study, 3.3 Ϯ 0.9). Implantation rates were 12% and 26% in the control and study groups, respectively. The clinical pregnancy rate was 23% in the control group and 64% in the study group when lysed cell removal was performed.