Relationship between the day of embryo transfer and the outcome in human in vitro fertilization and embryo transfer

Cryopreservation of incomplete compacted morulae and preliminary biopsy of excluded fragments

The complexity of predicting embryo development potential at the cleavage stages and the emergence of epigenetic risks during prolonged in vitro culture of pre-implantation embryos made it more advantageous to transfer embryos at the morula stage to the uterine cavity. The criteria for estimating embryos at this stage that allow prediction of cryopreservation outcomes have been poorly described. All day 4 embryos (n = 224) were graded 1, 2, 3, 4 or 5 according to blastomere compaction degree (BCD = 100, 75, 50, 25 or 0%, respectively) and the survival and blastocyst formation rate of these morulae were studied after cryopreservation. An inverse dependence was found between survival rate and BCD. Excluded fragments were characterized by low osmotic reaction during exposure to cryoprotective medium and, after freeze-thawing, they were destroyed. As damaged necrotic areas of the embryo can affect their further development rate we proposed blastomeres and biopsy fragments of incomplete compacted morula be removed before embryo cryopreservation. This step led to significant increase in the post-thawing survival rate up to 93.1 ± 4.1%, 75 ± 8.8% and blastocyst formation rate up to 85.2 ± 10.4%, 59.4 ± 5.2% in grade 2 and grade 3 embryos, respectively. There was no significant difference in grade 4 embryos. Therefore the removal of blastomeres and biopsy fragments in incomplete compacted morulae can improve cryopreservation outcomes of grade 2 and grade 3 embryos with BCD.

Should the flexibility enabled by performing a day-4 embryo transfer remain as a valid option in the IVF laboratory? A systematic review and network meta-analysis

PURPOSE

The present systematic review and network meta-analysis aims to uniquely bring to literature data supporting the true place of the alternative practice of day-4 embryo transfer (D4 ET) in an IVF laboratory, beyond the one-dimensional option of facilitating a highly demanding program.

METHODS

A systematic search was conducted in the databases of PubMed/Medline, Embase, and Cochrane Central Library, resulting to six prospective along with nine retrospective cohort studies meeting eligibility criteria for inclusion. A comparison of D4 ET with day-2 (D2), day-3 (D3), and day-5 (D5) ET, respectively, was performed employing R statistics.

RESULTS

The sourced results indicate no statistically significant difference regarding clinical pregnancy rates, and ongoing pregnancy/live birth rates stemming from the comparison of D4 with D2, D4 with D3, and D4 with D5 ET, respectively. Additionally, no statistically significant difference could be established in respect to cancelation, and miscarriage rates, following the comparison of D4 with D3 and D4 with D5 ET. Interestingly, we report statistically significant lower preterm birth rates associated with D4 ET, in contrast with D5 ET (RR, 0.19; 95% CI, 0.05-0.67; p value = 0.01).

CONCLUSIONS

The aforementioned results may serve as advocates buttressing the option of D4 ET as a valid candidate in the ET decision-making process. Possible limitations of the current study are the publication bias stemming from the retrospective nature of certain included studies, along with various deviations among studies' design, referring to number and quality of transferred embryos, or different culture conditions referring to studies of previous decades.

Day three versus day two embryo transfer following in vitro fertilization or intracytoplasmic sperm injection

BACKGROUND

Embryo transfer (ET) was traditionally performed two days after oocyte retrieval; however, developments in culture media have allowed embryos to be maintained in culture for longer periods. Delaying transfer from Day two to Day three would allow for further development of the embryo and might have a positive effect on pregnancy outcomes.

OBJECTIVES

To determine if there are any differences in live birth and pregnancy rates when embryo transfer is performed on day three after oocyte retrieval, compared with day two, in infertile couples undergoing treatment with in vitro fertilisation (IVF), including intracytoplasmic sperm injection (ICSI).

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group Specialised Register of Controlled Trials, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid), Embase (Ovid), PsycINFO (Ovid) from the inception of the databases to 26th April 2016. We also searched ClinicalTrials.gov and the WHO portal for ongoing trials plus citation lists of relevant publications, review articles and included studies, as well as abstracts of appropriate scientific meetings.

SELECTION CRITERIA

Randomised controlled trials that compared Day 3 versus Day 2 embryo transfer after oocyte retrieval during an IVF or ICSI treatment cycle in infertile couples.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. We contacted study authors for additional information. The primary outcome measures were live birth rate and ongoing pregnancy rate.

MAIN RESULTS

We included 15 studies. Fourteen studies reported data per woman (2894 women) and one study reported data per cycle (969 cycles). The quality of the evidence using the GRADE approach ranged from moderate quality to very low quality. The main reasons for downgrading evidence were poor methodological reporting, selective reporting, inconsistency and imprecision. Live birth per woman - Overall, there was no evidence of a difference in live birth rate between Day three and Day two embryo transfer (risk ratio (RR) 1.05, 95% confidence interval (CI) 0.89 to 1.23; three studies, n = 1200 women; I2 = 63%; very low quality evidence). The data suggest that if 32% of women who underwent a Day two embryo transfer had a live birth, then between 28% to 39% of women undergoing a Day three embryo transfer would have a live birth. Ongoing pregnancy per woman - There was no evidence of a difference between Day three and Day two embryo transfer for ongoing pregnancy (RR 0.98, 95% CI 0.85 to 1.12; six studies, n = 1740 women; I2 = 52%; very low quality of evidence). The data suggest that if 33% of women undergoing a Day two embryo transfer had an ongoing pregnancy then between 28% to 37% of women undergoing a Day three embryo transfer would have an ongoing pregnancy. Clinical pregnancy per woman - There was no evidence of a difference between Day three and Day two embryo transfer for the chance of a clinical pregnancy (RR 1.08, 95% CI 0.98 to 1.19; 12 studies, n = 2461, I2 = 51%; very low quality evidence). The data suggest that if 39% of women undergoing Day two embryo transfer had a clinical pregnancy, then between 38% to 46% of women undergoing a Day three embryo transfer would have a clinical pregnancy. Multiple pregnancy per woman - There was no evidence of a difference between Day three and Day two embryo transfer for the risk of a multiple pregnancy (RR 1.12, 95% CI 0.86 to 1.44; eight studies, n = 1837; I2 = 0%; moderate quality evidence). The data suggest that if 11% of women undergoing Day two embryo transfer had a multiple pregnancy, then between 9% to 15% of women undergoing a Day three embryo transfer would have a multiple pregnancy. Miscarriage rate per woman - There was no evidence of a difference between Day three and Day two embryo transfer for the risk of miscarriage (RR 1.16, 95% CI 0.84 to 1.60; nine studies, n = 2153 women, I2 = 26%; moderate quality evidence). The data suggest that if 6% of women undergoing Day two embryo transfer had a miscarriage, then between 5% to 10% of women undergoing a Day three embryo transfer would have a miscarriage. Ectopic pregnancy rate per woman - There was no evidence of a difference between Day three and Day two embryo transfer for the risk of ectopic pregnancy (RR 0.99, 95% CI 0.29 to 3.40; six studies, n = 1531 women, I2 = 0%; low quality evidence). The data suggest that if 0.7% of women undergoing Day two embryo transfer have an ectopic pregnancy, then between 0.2% to 2% of women undergoing Day three embryo transfer would have an ectopic pregnancy.Subgroup analysis for pregnancy outcomes did not identify any differential effect between IVF and ICSI.None of the included studies prespecified complication rate (e.g. OHSS), fetal abnormality or women's evaluation of the procedure as outcomes in their studies.

AUTHORS' CONCLUSIONS

Twelve of 15 studies contributed data that could be included in meta-analyses. The quality of the evidence ranged from moderate to very low. Only three of the 15 studies reported data for live birth, although the data for ongoing pregnancy and clinical pregnancy are consistent with the live birth data, suggesting no difference between Day three and Day two embryo transfer for these outcomes. There was no evidence of a difference identified between Day three and Day two embryo transfer for multiple pregnancy, miscarriage or ectopic pregnancy per woman randomised. No data were reported for complication rate, fetal abnormality or woman's evaluation of the procedure. The current evidence has not identified any evidence of differences in pregnancy outcomes between Day two and Day three embryo transfers. Any further studies comparing these timings of embryo transfer are unlikely to alter the findings and we suggest that this review no longer be updated.

Morphological assessment on day 4 and its prognostic power in selecting viable embryos for transfer

The aim of this study was to describe a system for embryo morphology scoring at the morula stage and to determine the efficiency of this model in selecting viable embryos for transfer. In total, 519 embryos from 122 patients undergoing intracytoplasmic sperm injection (ICSI) were scored retrospectively on day 4 according to the grading system proposed in this article. Two separate quality scores were assigned to each embryo in relation to the grade of compaction and fragmentation and their developmental fate was then observed on days 5 and 6. Secondly, the prediction value of this scoring system was compared with the prediction value of the traditional scoring system adopted on day 3. Morulas classified as grade A showed a significant higher blastocyst formation rate (87.2%) compared with grades B, C and D (63.8, 41.3 and 15.0%, respectively), (P < 0.001). Furthermore, the ability to form top quality blastocysts was significantly higher for grade A morulas with respect to grades B, and C and D (37.8% vs. 22.4% vs. 11.1%), (P < 0.001). Finally, the morula scoring system showed more prediction power with respect to the embryo scoring a value of 1 [Akaike information criterion (AIC) index 16.4 vs. 635.3 and Bayesian information criterion (BIC) index −68.8 vs. −30.0 for morulas and embryos respectively]. In conclusion, results demonstrated that the presented scoring system allows for the evaluation of eligible embryos for transfer as a significant correlation between the grade of morula, blastulation rate and blastocyst quality was observed. Furthermore, the morula scoring system was shown to be the best predictive model when compared with the traditional scoring system performed on day 3.

Day 4 versus day 3 embryo transfer: a prospective study of clinical outcomes

OBJECTIVE

To compare the clinical outcomes after day 4 or day 3 embryo transfers in controlled ovarian hyperstimulation-IVF/intracytoplasmic sperm injection (ICSI) cycles.

DESIGN

Prospective randomized study.

SETTING

Center for Human Reproduction, 'Genesis Athens' Clinic (private gynecological and surgical clinic), Athens, Greece.

PATIENT(S)

Three hundred fifty women with primary infertility and indication for IVF/ICSI treatment. Patients were randomly allocated to day 4 or day 3 embryo transfer.

INTERVENTION(S)

Controlled ovarian hyperstimulation, oocyte retrieval, IVF/ICSI, embryo transfer.

MAIN OUTCOME MEASURE(S)

Implantation rate; clinical, ongoing, and multiple pregnancy rates.

RESULT(S)

A trend toward higher clinical and ongoing pregnancy rates was noted after day 4 embryo transfers. Implantation and multiple pregnancy rates were comparable after day 4 or day 3 embryo transfers.

CONCLUSION(S)

The transfer of day 4 embryos in IVF/ICSI cycles may result in favorable implantation and pregnancy rates which are at least comparable to those after the transfer of day 3 embryos.

Developmentally retarded frozen blastocysts can be rescued by synchronizing culture prior to transfer

Asynchrony between embryo development and endometrial differentiation is the limiting step of successful pregnancy in assisted reproduction. The aim of this study was to investigate whether or not post-thaw synchronization culture of day 5-6 frozen embryos, prior to transfer, with endometrial differentiation resulted in pregnancy. A total of 142 cycles of 134 patients were transferred in three protocols. Blastocysts with cavities larger than half of the entire blastocyst volume were transferred without synchronizing culture on day 5 or 6 of progesterone commencement (P5/6) in hormone replacement treatment cycles (protocol 1). Blastocysts with cavitation below half of the entire blastocyst were cultured for 1 or 2 days after thawing prior to transfer on P5 or P6 (protocol 2). Morulae and very early stage blastocysts were thawed on the days corresponding to P5 and P6, and only the embryos that reached expanded or hatching blastocysts were transferred on P7 without synchronizing culture (protocol 3). Pregnancy rate in protocol 2 (32.0%) was comparable with that of protocol 1 (35.0%). It is concluded that developmentally retarded frozen embryos can be rescued with synchronizing culture prior to transfer by evading asynchrony.

Day three versus day two embryo transfer following in vitro fertilization or intracytoplasmic sperm injection

BACKGROUND

Embryo transfer (ET) was traditionally performed two days after oocyte retrieval; however, developments in culture media have allowed embryos to be maintained in culture for longer periods. Delaying transfer from day two to day three would allow for further development of the embryo and might have a positive effect on pregnancy outcomes.

OBJECTIVES

To determine if there is any difference in live birth and pregnancy rates when ET is performed on day three, compared with day two, in infertile couples undergoing treatment with in vitro fertilization (IVF), including intracytoplasmic sperm injection (ICSI).

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders & Subfertility Group trials register (17th December 2003), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2003), MEDLINE (1966 to 2003), EMBASE (1980 to 2003) and Biological Abstracts Databases (1980 to 2003), the National Research Register (NRR), the Medical Research Council's Clinical Trials Register, the NHS Centre for Reviews and Dissemination, citation lists of relevant publications, review articles and included studies, as well as abstracts of appropriate scientific meetings.

SELECTION CRITERIA

Randomized controlled trials that compared day three versus day two embryo transfer after oocyte retrieval during an IVF or ICSI treatment cycle in subfertile couples.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information. The primary outcome measures were live birth rate and ongoing pregnancy rate.

MAIN RESULTS

Ten studies involving 2027 women were included, but only three studies reported live birth and four reported ongoing pregnancy rates. The pooled odds ratios (day three compared to day two) were 1.07, 95% CI 0.84 to 1.37 for live birth and 1.05, 95% CI 0.83 to 1.32 for ongoing pregnancy. From ten studies, the pooled odds ratio for clinical pregnancy was 1.26, 95% CI 1.06 to 1.51. Sub-group analysis revealed that this advantage occurred in those undergoing ICSI cycles. A higher miscarriage rate with day 3 ET in ICSI cycles works to negate the increased clinical pregnancy rate, in agreement with the finding of no significant difference between treatments in live birth rate.

REVIEWERS' CONCLUSIONS

Although an increase in clinical pregnancy rate with day three embryo transfer was demonstrated, at present there is not sufficient good quality evidence to suggest an improvement in live birth when embryo transfer is delayed from day two to day three.

A prospective randomized multicenter study to evaluate the best day for embryo transfer: does the outcome justify prolonged embryo culture?

PURPOSE

This study aimed to evaluate the best day for embryo transfer in a prospective unrestricted randomized multicenter trial.

METHODS

Data were collected on a preformed Excel-sheet which contained random numbers from 1 to 5 for each subsequent patient as a preprogrammed day for embryo transfer. Information was requested on patient's age, indication for sterility treatment, stimulation protocol used, numbers of oocytes retrieved, fertilized oocytes, cryopreserved embryos, and cell stage of embryos transferred.

RESULTS

A total of 329 embryo transfers were performed, resulting in 106 clinical pregnancies (32.2%). Pregnancy rates achieved were 20.0% on day 1, 30.4% on days 2 and 3, and 50.0% on days 4 and 5 (p = 0.03).

CONCLUSIONS

Within the scope of the present randomized multicenter trial, embryo transfers performed on days 4 and 5 enhanced the pregnancy rate significantly, compared to those of days 1, 2, and 3.

Improved clinical outcomes for in vitro fertilization with delay of embryo transfer from 48 to 72 hours after oocyte retrieval: use of glucose- and phosphate-free media

OBJECTIVE

To evaluate clinical outcomes of day 2 versus day 3 ET using a culture media with no glucose or phosphate.

DESIGN

Retrospective clinical study.

SETTING

Hospital-based fertility clinic.

PATIENT(S)

One hundred seventy-six IVF-ET patients undergoing controlled ovarian supraovulation.

INTERVENTION(S)

IVF and delaying the ET by 1 day.

MAIN OUTCOME MEASURE(S)

Number of blastomeres per embryo, implantation and pregnancy rates.

RESULT(S)

Delaying the ET from day 2 to day 3 after oocyte retrieval significantly increased implantation rates (13% versus 24%) and ongoing/delivered pregnancy rates per retrieval (26% versus 44%). Day 3 embryos with > or = 8 blastomeres resulted in a significantly higher pregnancy rate (53%) than day 3 embryos with < 8 cells (23%) and day 2 embryos with > or = 4 cells (31%) or < 4 cells (11%).

CONCLUSION(S)

Day 3 ET was associated with a significant increase in implantation and pregnancy rates. Delaying the ET until day 3 may permit the selection of more viable embryos than on day 2. The absence of glucose and phosphate from the culture media is compatible with good IVF outcomes.