Cleavage stage versus blastocyst stage embryo transfer in assisted conception

Establishment and validation of a nomogram for subsequent first-cycle live births in patients diagnosed with recurrent implantation failure: a population-based analysis

Background

The inability of patients with recurrent implantation failure (RIF) to achieve pregnancy and a live birth after multiple high-quality embryo transfer treatments has been recognized as a major obstacle to successful application of artificial reproductive technologies. The objective of this study was to establish and validate a nomogram for prediction of subsequent first-cycle live births to guide clinical practice in patients diagnosed with RIF.

Methods

A total of 538 patients who underwent in vitro fertilization/intracytoplasmic sperm injection treatment and were first diagnosed with RIF at the Reproductive Center of the First Affiliated Hospital of Xinjiang Medical University between January 2017 and December 2020 were enrolled. The patients were randomly divided into a training cohort (n=408) and a validation set (n=175) in a ratio of 7:3. A nomogram model was constructed using the training set based on the results of univariate and multivariate logistic regression analyses and validated in the validation set.

Results

Age, body mass index, duration of RIF, endometrial thickness, type of embryo transferred, and number of previous biochemical pregnancies were included in the nomogram for prediction of subsequent first-cycle live births in patients diagnosed with RIF. Analysis of the area under the receiver-operating characteristic curve, calibration plots, and decision curve analysis showed that our predictive model for live births had excellent performance.

Conclusion

We have developed and validated a novel predictive model that estimates a woman's chances of having a live birth after a diagnosis of RIF and provides clinicians with a personalized clinical decision-making tool.

Cleavage-stage versus blastocyst-stage embryo transfer in assisted reproductive technology

BACKGROUND

Advances in embryo culture media have led to a shift in in vitro fertilisation (IVF) practice from cleavage-stage embryo transfer to blastocyst-stage embryo transfer. The rationale for blastocyst-stage transfer is to improve both uterine and embryonic synchronicity and enable self selection of viable embryos, thus resulting in better live birth rates.

OBJECTIVES

To determine whether blastocyst-stage (day 5 to 6) embryo transfer improves the live birth rate (LBR) per fresh transfer, and other associated outcomes, compared with cleavage-stage (day 2 to 3) embryo transfer.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group Specialised Register of controlled trials, CENTRAL, MEDLINE, Embase, PsycINFO, and CINAHL, from inception to October 2021. We also searched registers of ongoing trials and the reference lists of studies retrieved.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) which compared the effectiveness of IVF with blastocyst-stage embryo transfer versus IVF with cleavage-stage embryo transfer.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. Our primary outcomes were LBR per fresh transfer and cumulative clinical pregnancy rates (cCPR). Secondary outcomes were clinical pregnancy rate (CPR), multiple pregnancy, high-order multiple pregnancy, miscarriage (all following first embryo transfer), failure to transfer embryos, and whether supernumerary embryos were frozen for transfer at a later date (frozen-thawed embryo transfer). We assessed the overall quality of the evidence for the main comparisons using GRADE methods.

MAIN RESULTS

We included 32 RCTs (5821 couples or women). The live birth rate following fresh transfer was higher in the blastocyst-stage transfer group (odds ratio (OR) 1.27, 95% confidence interval (CI) 1.06 to 1.51; I² = 53%; 15 studies, 2219 women; low-quality evidence). This suggests that if 31% of women achieve live birth after fresh cleavage-stage transfer, between 32% and 41% would do so after fresh blastocyst-stage transfer. We are uncertain whether blastocyst-stage transfer improves the cCPR. A post hoc analysis showed that vitrification could increase the cCPR. This is an interesting finding that warrants further investigation when more studies using vitrification are published. The CPR was also higher in the blastocyst-stage transfer group, following fresh transfer (OR 1.25, 95% CI 1.12 to 1.39; I² = 51%; 32 studies, 5821 women; moderate-quality evidence). This suggests that if 39% of women achieve a clinical pregnancy after fresh cleavage-stage transfer, between 42% and 47% will probably do so after fresh blastocyst-stage transfer. We are uncertain whether blastocyst-stage transfer increases multiple pregnancy (OR 1.05, 95% CI 0.83 to 1.33; I² = 30%; 19 studies, 3019 women; low-quality evidence) or miscarriage rates (OR 1.12, 95% CI 0.90 to 1.38; I² = 24%; 22 studies, 4208 women; low-quality evidence). This suggests that if 9% of women have a multiple pregnancy after fresh cleavage-stage transfer, between 8% and 12% would do so after fresh blastocyst-stage transfer. However, a sensitivity analysis restricted only to studies with low or 'some concerns' for risk of bias, in the subgroup of equal number of embryos transferred, showed that blastocyst transfer probably increases the multiple pregnancy rate. Embryo freezing rates (when there are frozen supernumerary embryos for transfer at a later date) were lower in the blastocyst-stage transfer group (OR 0.48, 95% CI 0.40 to 0.57; I² = 84%; 14 studies, 2292 women; low-quality evidence). This suggests that if 60% of women have embryos frozen after cleavage-stage transfer, between 37% and 46% would do so after blastocyst-stage transfer. Failure to transfer any embryos was higher in the blastocyst transfer group (OR 2.50, 95% CI 1.76 to 3.55; I² = 36%; 17 studies, 2577 women; moderate-quality evidence). This suggests that if 1% of women have no embryos transferred in planned fresh cleavage-stage transfer, between 2% and 4% probably have no embryos transferred in planned fresh blastocyst-stage transfer. The evidence was of low quality for most outcomes. The main limitations were serious imprecision and serious risk of bias, associated with failure to describe acceptable methods of randomisation.

AUTHORS' CONCLUSIONS

There is low-quality evidence for live birth and moderate-quality evidence for clinical pregnancy that fresh blastocyst-stage transfer is associated with higher rates of both than fresh cleavage-stage transfer. We are uncertain whether blastocyst-stage transfer improves the cCPR derived from fresh and frozen-thawed cycles following a single oocyte retrieval. Although there is a benefit favouring blastocyst-stage transfer in fresh cycles, more evidence is needed to know whether the stage of transfer impacts on cumulative live birth and pregnancy rates. Future RCTs should report rates of live birth, cumulative live birth, and miscarriage. They should also evaluate women with a poor prognosis to enable those undergoing assisted reproductive technology (ART) and service providers to make well-informed decisions on the best treatment option available.

Prediction of embryo implantation rate using a sole parameter of timing of starting blastulation

A time-lapse monitoring system provides a complete picture of the dynamic embryonic development process and simultaneously supplies extensive morphokinetic data. The objective of this study was to investigate whether the use of the morphokinetic parameter of time of starting blastulation (tSB) can improve the implantation rate of day-5 transferred blastocyst selected based on morphological parameters. In this retrospective study we analyzed the morphokinetics of 196 day-5 transferred blastocysts, selected solely based on morphological parameters. The interval time from intracytoplasmic sperm injection (ICSI) to time of starting blastocyst formation (tSB) was calculated for each embryo. The overall implantation rate of transferred blastocyst, selected based only on morphological parameters, was 49.2%. Implantation rate, determined retrospectively, was significantly higher (58.8% versus 42.6%, P = 0.02) for embryos with a short interval time to tSB (78-95.9 h) compared with embryos with a longer timeframe (96-114 h). Time of expanded blastocyst (tEB) post-ICSI was also significantly associated with implantation; however, this parameter was not available for all the embryos at time of transfer. When we tested only high ranked KIDScore day-3 sub-group embryos, the implantation rate was significantly higher in short interval time embryos compared with longer interval time embryos (62.2% vs. 45.5%, respectively, P = 0.02).These observations emphasize the importance of the timing of starting blastulation over blastocyst morphological parameters and may provide a preferable criterion for good morphology day-5 blastocyst selection.

Application of a Nomogram for Predicting the Risk of Subchorionic Hematoma in Early Pregnancy With In Vitro Fertilization-Embryo Transfer/Frozen Embryo Transfer

BACKGROUND

Subchorionic hematoma (SCH) is common in early pregnancy achieved by in vitro fertilization-embryo transfer/frozen embryo transfer (IVF-ET/FET), and is associated with adverse obstetric outcomes. However, there are no methods known to accurately predict the occurrence of SCH.

OBJECTIVE

To establish a nomogram prediction model for predicting the risk of SCH in early pregnancy with IVF-ET/FET and to analyze pregnancy outcomes of patients with SCH.

METHODS

Patients who underwent IVF-ET/FET treatment and were diagnosed with clinical pregnancy were enrolled in our study. A total of 256 patients with SCH were enrolled in the SCH group, and 526 patients without SCH in the control group. Logistic regression was used to screen risk factors for SCH, and the nomogram was developed according to the regression coefficient of relevant variables. Discrimination, effect, calibration, and the predictive model's clinical usefulness were assessed using the C-index, the area under the receiver operating characteristic standard curve, calibration plot, and decision curve analysis. Internal validation was assessed using bootstrapping validation. The effects of SCH on pregnancy outcomes were analyzed.

RESULTS

A multivariate logistic regression analysis showed that fresh embryo transfer, polycystic ovary syndrome, hydrosalpinx, and thin endometrium were risk factors affecting the occurrence of SCH. Based on the above factors, a predictive model for the risk of SCH was created. The model displayed good discrimination, with a C-index of 0.783 (95% confidence interval: 0.750-0.816), area under the receiver operating characteristic standard curve of 0.783, and good calibration. A high C-index value of 0.765 could still be reached in the interval validation. Decision curve analysis showed that the nomogram was clinically useful when the intervention was decided at the SCH possibility threshold of 4%-87%. For patients with successful deliveries, the occurrence of SCH did not influence the gestational weeks of delivery, mode of delivery, preterm birth, height, and weight of the newborn.

CONCLUSION

We screened the risk factors for SCH in patients who underwent IVF-ET/FET treatment. Successful establishment of a nomogram can effectively predict the occurrence of SCH. Furthermore, the incidence of miscarriage is higher in patients with SCH.

Comparison of pregnancy outcomes after vitrification at the cleavage and blastocyst stage: a meta-analysis

OBJECTIVE

This systematic review sought to evaluate the clinical outcomes of vitrification at the cleavage stage and blastocyst stage for embryo transfer in patients undergoing assisted reproductive technology (ART) treatment.

METHODS

We searched for related comparative studies published in the PubMed, EMBASE, and Cochrane Library databases up to July 2017. The primary outcomes were clinical pregnancy rate (CPR) and embryo implantation rate (IR). Secondary outcomes were multiple pregnancy rate (MPR), miscarriage rate (MR), live birth rate (LBR), and ongoing pregnancy rate (OPR). The Mantel-Haenszel fixed effects model and random effects model were used to analyze the summary risks ratios (RRs) with 95% confidence intervals (CIs).

RESULTS

Eight studies with more than 6590 cycles were included in our meta-analysis. Seven studies were observational retrospective comparative studies. One was a prospective study. Overall, the current study summarizes information from 6590 vitrification warming cycles (cleavage stage n = 4594; blastocysts n = 1996). There was no difference in the primary outcome clinical pregnancy rate (RR = 0.97, 95% CI = 0.90-1.04; fixed effects model; I ²  = 21%), whereas vitrified blastocyst transfer was significantly superior to vitrified cleavage-stage embryo transfer regarding the implantation rate (RR = 0.85, 95% CI = 0.74-0.97; random effects model; I ²  = 43). Regarding the secondary outcomes, no differences were found in the multiple pregnancy rate (RR = 1.20, 95% CI = 0.79-1.82; fixed effects model; I ²  = 22), live birth rate (RR = 1.07, 95% CI = 0.98-1.16; fixed effects model; I ²  = 0), and ongoing pregnancy rate (RR = 1.01, 95% CI = 0.92-1.120; fixed effects model; I ²  = 0), whereas a higher miscarriage rate was observed with vitrified blastocyst transfer (RR = 0.65, 95% CI = 0.45-0.93; random effects model; I ²  = 23).

CONCLUSION

In summary, this meta-analysis shows that vitrification at any stage has no detrimental effect on clinical outcome. Blastocyst transfer will still remain a favorable and promising option in ART. Due to the small sample evaluated in the pool of included studies, large-scale, prospective, and randomized controlled trials are required to determine if these small effects are clinically relevant.

Cleavage stage versus blastocyst stage embryo transfer in assisted reproductive technology

BACKGROUND

Advances in cell culture media have led to a shift in in vitro fertilisation (IVF) practice from cleavage stage embryo transfer to blastocyst stage transfer. The rationale for blastocyst transfer is to improve both uterine and embryonic synchronicity and enable self selection of viable embryos, thus resulting in better live birth rates.

OBJECTIVES

To determine whether blastocyst stage (day 5 to 6) embryo transfers improve the live birth rate, and other associated outcomes, compared with cleavage stage (day 2 to 3) embryo transfers.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group Specialised Register of controlled trials, Cochrane Central Register of Controlled Trials (CENTRAL; the Cochrane Library; 2016, Issue 4), MEDLINE, EMBASE, PsycINFO, CINAHL, and Bio extracts from inception to 4th April 2016. We also searched registers of ongoing trials and the reference lists of studies retrieved.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) which compared the effectiveness of blastocyst versus cleavage stage transfers.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. Our primary outcomes were live birth and cumulative clinical pregnancy rates. Secondary outcomes were clinical pregnancy, multiple pregnancy, high order pregnancy, miscarriage, failure to transfer embryos, and embryo freezing. We assessed the overall quality of the evidence for the main comparisons using GRADE methods.

MAIN RESULTS

We included 27 RCTs (4031 couples or women).The live birth rate following fresh transfer was higher in the blastocyst transfer group (odds ratio (OR) 1.48, 95% confidence interval (CI) 1.20 to 1.82; 13 RCTs, 1630 women, I(2) = 45%, low quality evidence) following fresh transfer. This suggests that if 29% of women achieve live birth after fresh cleavage stage transfer, between 32% and 42% would do so after fresh blastocyst stage transfer.There was no evidence of a difference between the groups in rates per couple of cumulative pregnancy following fresh and frozen-thawed transfer after one oocyte retrieval (OR 0.89, 95% CI 0.64 to 1.22; 5 RCTs, 632 women, I(2) = 71%, very low quality evidence).The clinical pregnancy rate was also higher in the blastocyst transfer group, following fresh transfer (OR 1.30, 95% CI 1.14 to 1.47; 27 RCTs, 4031 women, I(2) = 56%, moderate quality evidence). This suggests that if 36% of women achieve clinical pregnancy after fresh cleavage stage transfer, between 39% and 46% would do so after fresh blastocyst stage transfer.There was no evidence of a difference between the groups in rates of multiple pregnancy (OR 1.05, 95% CI 0.83 to 1.33; 19 RCTs, 3019 women, I(2) = 30%, low quality evidence), or miscarriage (OR 1.15, 95% CI 0.88 to 1.50; 18 RCTs, 2917 women, I(2) = 0%, low quality evidence). These data are incomplete as under 70% of studies reported these outcomes.Embryo freezing rates were lower in the blastocyst transfer group (OR 0.48, 95% CI 0.40 to 0.57; 14 RCTs, 2292 women, I(2) = 84%, low quality evidence). This suggests that if 60% of women have embryos frozen after cleavage stage transfer, between 37% and 46% would do so after blastocyst stage transfer. Failure to transfer any embryos was higher in the blastocyst transfer group (OR 2.50, 95% CI 1.76 to 3.55; 17 RCTs, 2577 women, I(2) = 36%, moderate quality evidence). This suggests that if 1% of women have no embryos transferred in (planned) fresh cleavage stage transfer, between 2% and 4% will have no embryos transferred in (planned) fresh blastocyst stage transfer.The evidence was of low quality for most outcomes. The main limitation was serious risk of bias, associated with failure to describe acceptable methods of randomisation, and unclear or high risk of attrition bias.

AUTHORS' CONCLUSIONS

There is low quality evidence for live birth and moderate quality evidence for clinical pregnancy that fresh blastocyst stage transfer is associated with higher rates than fresh cleavage stage transfer. There was no evidence of a difference between the groups in cumulative pregnancy rates derived from fresh and frozen-thawed cycles following a single oocyte retrieval, but the evidence for this outcome was very low quality. Thus, although there is a benefit favouring blastocyst transfer in fresh cycles, it remains unclear whether the day of transfer impacts on cumulative live birth and pregnancy rates. Future RCTs should report rates of live birth, cumulative live birth, and miscarriage to enable couples or women undergoing assisted reproductive technology (ART) and service providers to make well informed decisions on the best treatment option available.

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.

Current status of the approach to assisted reproduction

Assisted reproductive technologies are important tools in the clinical armamentarium used to treat both female and male infertility disorders. Pre-implantation genetic diagnosis offers couples at risk of having children with inheritable disorders the ability to analyze the genetic make-up of embryos before transfer. For patients undergoing treatment of cancer with chemotherapy or radiation therapy, these technologies offer the potential for the preservation of future fertility. As technology evolves, it is likely the clinical applications of assisted reproduction will continue to develop and expand in the future to enhance fertility.

Embryo quality and impact of specific embryo characteristics on ongoing implantation in unselected embryos derived from modified natural cycle in vitro fertilization

OBJECTIVE

To study the implantation potential of unselected embryos derived from modified natural cycle IVF according to their morphological characteristics.

DESIGN

Cohort study.

SETTING

Academic department of reproductive medicine.

PATIENT(S)

A series of 449 single embryo transfers derived from modified natural cycle IVF.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Ongoing implantation rate according to embryo characteristics.

RESULT(S)

The best implantation was found in embryos with 4 and 8 cells on day 2 and 3 respectively, <or=10% fragmentation, and absence of multinucleated blastomeres. In contrast to findings from other studies, we found embryos with fewer than four blastomeres on day 2 to do relatively well. Furthermore, we found the implantation potential of embryos containing multinucleated blastomeres to be less severely impaired than expected.

CONCLUSION(S)

Findings from this study suggest that in currently used embryo scoring systems, the implantation potential of embryos with low numbers of blastomeres on day 2, as well as embryos containing multinucleated blastomeres, is underestimated. However, it is unclear whether the results of our study apply to embryos derived from controlled ovarian hyperstimulation cycles.

Stimulation of endometrium embryo transfer can improve implantation and pregnancy rates for patients undergoing assisted reproductive technology for the first time with a high-grade blastocyst

OBJECTIVE

To evaluate whether stimulation of endometrium embryo transfer (SEET) can improve implantation rate and pregnancy rate (PR) for patients undergoing assisted reproductive technology (ART) for the first time by injecting embryo culture supernatant into the uterus before blastocyst transfer (BT).

DESIGN

Randomized, controlled trial.

SETTING

Private in vitro fertilization clinic.

PATIENT(S)

Forty-eight women in the BT group, 48 women in the stimulation group who had culture medium injected into the uterus before BT, and 48 women in the SEET group.

INTERVENTION(S)

Injection of embryo culture supernatant and injection of culture medium.

MAIN OUTCOME MEASURE(S)

Implantation rates and PRs.

RESULT(S)

Odds ratios of successful implantation rate for stimulation and SEET in patients with high-grade blastocysts, having BT as reference, were 2.58 and 6.46 without adjustment, and 5.91 and 9.20 after adjusting for basal FSH levels and period of infertility. Odds ratios of clinical pregnancies were 2.47 and 4.32 without adjustment, and 4.46 and 5.10 with adjustment, respectively. In groups with low-grade blastocysts, such tendencies were not observed.

CONCLUSION(S)

The SEET may be an effective method for increasing implantation rate and PR for first-time ART patients who have a high-grade blastocyst.

Live birth sex ratios are not influenced by blastocyst-stage embryo transfer

OBJECTIVE

To analyze the sex ratio of infants born after blastocyst-stage transfer of embryos with normal preimplantation FISH genetic screening.

DESIGN

Retrospective cohort analysis.

SETTING

Large academic assisted reproductive technology center.

PATIENT(S)

Two hundred twenty-eight patients undergoing fresh IVF cycle with blastocyst transfer.

INTERVENTION(S)

Preimplantation genetic screening for sex complement.

MAIN OUTCOME MEASURE(S)

Sex ratio in liveborn infants following blastocyst transfer.

RESULT(S)

One thousand thirteen embryos were normal by preimplantation genetic screening of chromosomes 13, 15, 16, 17, 18, 21, 22, X, and Y. Four hundred ninety-eight normal embryos were transferred to 228 patients with an overall live birth rate of 41.7%. Transferred blastocysts were selected based upon morphologic assessment. When controlling for the sex of the blastocyst embryo, there was no difference in the male-to-female delivery rate per embryo transferred (27.3% vs. 21.4%) (relative risk =1.28, confidence interval 0.93-1.74). Of the live births 51.7% were male and 48.3% were female (P=.61). Subanalysis revealed no difference in male-to-female delivery rates in groups with a 1:1 ratio of male:female embryos transferred, a non 1:1 ratio transferred, or single-sex transfers.

CONCLUSION(S)

Blastocyst-stage embryo transfer does not influence the live birth sex ratio of embryos with normal preimplantation FISH genetic screening.

Significant reduction of twins with single embryo transfer in IVF

Multiple pregnancies in assisted reproduction can be regarded as iatrogenic and avoidable, given that the phenomenon is related to the number of embryos replaced. Prospective studies have shown that transferring one fresh embryo and subsequently one frozen embryo gives similar cumulative pregnancy rates to transferring two fresh embryos. However, the multiple pregnancy rates differ significantly between the two strategies. In Trondheim, elective double embryo transfer (eDET) was introduced in September 1991. Prior to that, multiple pregnancy rates were nearly 35% and the triplet rate was 7%. The triplet rate dropped to below 1%, but the twin rate still remained high. In 2002, it was decided to start elective single embryo transfer (eSET) and currently SET is performed in more than 90% of in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles. The inclusion criteria are nearly as simple as: 'If you have two good embryos, you get only one embryo at a time'. Multiple pregnancy rates are well below 10% and there are no triplets. In conclusion, triplet rates can be reduced to zero and twin rates to below 10% by eSET. The cumulative pregnancy rate per oocyte recovery is not reduced, including replacement of frozen- thawed embryos.

Stimulation of endometrium embryo transfer (SEET): injection of embryo culture supernatant into the uterine cavity before blastocyst transfer can improve implantation and pregnancy rates

OBJECTIVE

To evaluate whether stimulation of endometrium embryo transfer (SEET) by injecting embryo culture supernatant (ECS) into the uterus before blastocyst transfer (BT) can improve implantation and pregnancy rates.

DESIGN

Randomized, controlled trial.

SETTING

Private in vitro fertilization clinic.

PATIENT(S)

23 women in the SEET group, and 25 women in the control group.

INTERVENTION(S)

Injection of ECS.

MAIN OUTCOME MEASURE(S)

Implantation rates, pregnancy rates, and serum beta human chorionic gonadotropin (beta-hCG) levels at 4 weeks and 1 day of gestation.

RESULT(S)

Communication between the embryo and the endometrium (cross-talk) plays an important role in implantation. Several embryonic factors that modulate endometrial receptivity have been detected in ECS. In BT, cross-talk is absent until the blastocysts are transferred, so we injected ECS into the uterine cavity before BT to stimulate the endometrium and provide an optimum environment for implantation of forthcoming blastocysts. The implantation rates, pregnancy rates, and beta-hCG levels in the SEET group were statistically significantly higher than those in the BT control group.

CONCLUSION(S)

A novel method of embryo transfer based on the concept of embryo-dependent induction of endometrial receptivity, SEET may be an effective option for increasing implantation and pregnancy rates.

Live birth rates after transfer of equal number of blastocysts or cleavage-stage embryos in IVF. A systematic review and meta-analysis

BACKGROUND

Both cleavage-stage and blastocyst-stage embryo transfer policies have advantages and drawbacks. The number of embryos transferred, however, is a crucial parameter that needs to be considered before attempting any comparison.

METHODS

An extensive literature search yielded initially 282 studies from which 8 randomized controlled trials met the inclusion criteria: (i) truly randomized design (ii) policy to transfer equal number of embryos in both the cleavage-stage and the blastocyst-stage groups and (iii) published as full text in a peer-review journal. Primary outcome was the live birth rate and secondary outcomes were clinical pregnancy rate, multiple pregnancy rate, cancellation rate and cryopreservation rate.

RESULTS

A total of 1654 patients were reviewed. Live birth rate per randomized patient was significantly higher (n = 6 studies) in patients who had a blastocyst-stage transfer as compared to patients with cleavage-stage embryo transfer [odds ratio (OR): 1.39, 95% confidence interval (CI): 1.10-1.76; P = 0.005]. Clinical pregnancy rate (OR: 1.27, 95% CI: 1.03-1.55; P = 0.02) and cancellation rate per patient randomized (OR: 2.21, 95% CI: 1.47-3.32; P = 0.0001) were significantly higher in patients with a blastocyst-stage embryo transfer as compared to patients in whom a cleavage-stage embryo transfer was performed. The cryopreservation rate was significantly higher in the cleavage-stage group (OR: 0.28, 95% CI: 0.14-0.55; P = 0.0002).

CONCLUSIONS

The best available evidence suggests that the probability of live birth after fresh IVF is significantly higher after blastocyst-stage embryo transfer as compared to cleavage-stage embryo transfer when equal number of embryos are transferred in the two groups compared.

Murine pre-embryo oxygen consumption and developmental competence

PURPOSE

In search for a new marker of preimplantation embryo viability the present study investigated oxygen consumption of individual cleavage stage murine embryos, and evaluated the predictive value regarding subsequent development to expanded blastocysts.

METHODS

In all, 248 embryos were investigated from 2 cell stage until blastocyst stage with individual measurement of oxygen consumption and recording of developmental stage. Cleavage stage embryos and morula were divided in groups according to their oxygen consumption, and odds ratios (OR) for subsequent development to expanded blastocyst were calculated.

RESULTS

Cleavage stage (2-8 cell) individual oxygen consumption was 0.16-0.20 nl O(2) h(-1), with a significant increase to 0.21-0.23 nl O(2) h(-1) at the morula stage followed by a more than twofold increase for the expanded blastocyst 0.47 nl O(2) h(-1). A significantly higher chance of reaching the expanded blastocyst stage was found in 4-cell embryos with high oxygen consumption, than embryos with low consumption (OR 2.25, 95% CI 1.04-4.90). Among 2-cell embryos the chance of low and high consumers was not significantly different. The method used in the present study somewhat compromised embryo development (51% blastocyst rate) compared to controls (80% blastocystrate) which could make our results less robust.

CONCLUSION

Preliminary data from the present study suggest that oxygen consumption in cleavage stage embryos may be an indicator, but a not a strong predictor, of subsequent development to expanded blastocysts.

Human embryos developing in vitro are susceptible to impaired epithelial junction biogenesis correlating with abnormal metabolic activity

BACKGROUND

Blastocyst biogenesis occurs over several cell cycles during the preimplantation period comprising the gradual expression and membrane assembly of junctional protein complexes which distinguish the outer epithelial trophectoderm (TE) cells from the inner cell mass (ICM). In the human, TE integrity and the formation of a junctional seal can often be impaired. Embryos likely to result in a successful pregnancy after transfer are mostly selected according to morphological criteria. Recent data suggest that non-invasive measurement of amino acid turnover may be useful to complement such morphological scores. Whether morphological and metabolic criteria can be linked to poor TE differentiation thereby underpinning developmental predictions mechanistically remains unknown.

METHODS

We examined TE intercellular junction formation in human embryos by immunofluorescence and confocal microscopy and correlated this process with morphological criteria and amino acid turnover during late cleavage.

RESULTS

Our results show that TE differentiation may be compromised by failure of membrane assembly of specific junction constituents. This abnormality relates more closely to metabolic profiles than morphological criteria.

CONCLUSION

Our data identify that amino acid turnover can predict TE differentiation. These findings are the first to link two mechanisms, metabolism and junction membrane assembly, which contribute to early embryo development.

The role of the endometrium and embryo in human implantation

Despite many advances in assisted reproductive technologies (ART), implantation rates are still low. The process of implantation requires a reciprocal interaction between blastocyst and endometrium, culminating in a small window of opportunity during which implantation can occur. This interaction involves the embryo, with its inherent molecular programme of cell growth and differentiation, and the temporal differentiation of endometrial cells to attain uterine receptivity. Implantation itself is governed by an array of endocrine, paracrine and autocrine modulators, of embryonic and maternal origin. Implantation failure is thought to occur as a consequence of impairment of embryo developmental potential and/or impairment of uterine receptivity and the embryo-uterine dialogue. Therefore a better comprehension of implantation, and the relative importance of the factors involved, is warranted. New techniques for monitoring changes in the endometrium and/or the embryo at the level of gene regulation and protein expression may lead to the identification of better markers for implantation. Moreover, the use of predictive sets of markers may prove to be more reliable than a single marker. Continuing refinements to ART protocols, such as optimizing ovarian stimulation regimens, the timing of human chorionic gonadotrophin injection, or the timing of embryo transfer, should help to increase implantation rates further.

Aneuploidy in the miscarriages of infertile women and the potential benefit of preimplanation genetic diagnosis

OBJECTIVE

To evaluate the frequency of specific aneuploidies in miscarriages in an infertility practice and calculate the potential sensitivities of the different aneuploidy screening options for preimplantation genetic diagnosis (PGD) in this setting.

DESIGN

Retrospective analysis.

SETTING

Academic reproductive endocrinology and infertility practice.

PATIENT(S)

Women with miscarriages that had karyotype analysis on products of conception.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Karyotype of spontaneous abortions compared with commercially available PGD options.

RESULT(S)

Of the 273 karyotypes analyzed, 177 (64.8%) were abnormal. The average age of the patients was 37 +/- 4.5 years. Using a limited five-probe panel, 54 of the 177 (31%) abnormal karyotypes would have been detected. In contrast, an extended PGD panel (using 9, 10, or 12 chromosome probes) would have detected 127, 131, and 140 of 177 abnormalities, 72%, 74%, and 79% respectively. The difference between the limited (5-probe) and extended (9-, 10-, and 12-probe) panels was statistically significant. There was not a statistically significant difference among the extended panels.

CONCLUSION(S)

Most of the abnormalities seen in miscarriages are detectable by PGD with extended panels. A significantly higher percentage of these abnormalities could be detected by screening for 9, 10, or 12 chromosomes compared with only 5.

Triggering final oocyte maturation using different doses of human chorionic gonadotropin: a randomized pilot study in patients with polycystic ovary syndrome treated with gonadotropin-releasing hormone antagonists and recombinant follicle-stimulating hormone

OBJECTIVE

To evaluate the effect of different human chorionic gonadotropin (hCG) doses on the ongoing pregnancy rates in patients with polycystic ovary syndrome (PCOS).

DESIGN

Prospective, randomized, controlled trial.

SETTING

Tertiary university referral center.

PATIENT(S)

Eighty PCOS patients.

INTERVENTION(S)

Patients were randomized to receive 10,000 IU (n = 28), 5000 IU (n = 26), or 2500 IU (n = 26) of hCG for triggering final oocyte maturation as soon as >or=3 or more follicles of 17 mm or larger were present at ultrasound. Patients were stimulated with recombinant follicle stimulating hormone (FSH) and daily gonadotropin-releasing hormone (GnRH) antagonist, starting on day 6 of stimulation.

MAIN OUTCOME MEASURE(S)

Ongoing pregnancy, fertilization rates.

RESULT(S)

The median fertilization rates were 52.8%, 65.4%, and 55.6% after administration of 10,000 IU, 5000 IU and 2500 IU, respectively. The ongoing pregnancy rates per PCOS patient receiving hCG were 26.9% (7 of 26), 30.8% (8 of 26) and 34.8% (8 of 23), respectively.

CONCLUSION(S)

A decrease in the dose of hCG used to trigger final oocyte maturation does not appear to affect adversely the probability of pregnancy in PCOS patients treated by IVF using GnRH antagonists and recombinant FSH, and further testing in future larger-scale trials is recommended.

A retrospective comparison of clinical outcomes and satisfaction using reconstituted recombinant gonadotropins (rFSH) or cartridge rFSH with a pen device in donor oocyte cycles

BACKGROUND

Use of recombinant follicle stimulating hormone (rFSH) in a cartridge pen device offers obvious benefits for donor oocyte cycles including the administration of fewer and more patient-friendly injectable medications.

METHODS

In a University-based IVF program, a total of 98 oocyte donor cycles using rFSH either reconstituted or as a pen device given to 118 recipients (eight split cycles) were retrospectively reviewed. Following discontinuation of oral contraceptive, controlled ovarian hyperstimulation was begun using either reconstituted rFSH (n = 19) or rFSH with a cartridge pen device (n = 79) (150-300 IU qd). GnRH-antagonists (Ganirelix, Organon) and an additional 75 IU of rFSH/day were begun when lead follicles were 13-14 mm in greatest diameter. The primary endpoints analyzed included cycle stimulation characteristics for each donor group and donor medication tolerance assessment with respect to each rFSH formulation, while secondary outcome measures included clinical pregnancy and implantation rates.

RESULTS

Oocyte donors using the pen required significantly less rFSH (2734 IU vs. 3276 IU, p < 0.05) and scored significantly higher medication tolerance scores (3.9 +/- 0.4 vs. 3.1 +/- 0.6, p < 0.05). No other differences in cycle stimulation for oocyte donors and clinical outcomes for recipients were seen including pregnancy rates (pen, 77% vs. reconstituted, 55%, p - NS) and clinical pregnancy rates (61% vs. 45%, p - NS). However, significantly greater implantation rates (57% vs. 31%, p < 0.01) occurred in the pen group.

CONCLUSION

Compared to reconstituted formulations, the pen device results in lower gonadotropin requirements and provides a simplified dosing method with better tolerance.

Preferable correlation to blastocyst development and pregnancy rates with a new embryo grading system specific for day 3 embryos

PURPOSE

To investigate the cleavage stage embryo quality by the correlation between the morphological features and blastocyst development rate to develop a new embryo grading system.

METHODS

A retrospective analysis, including 216 cycles of cleavage stage embryo transfer and 251 cycles of blastocyst transfer. The correlation with blastocyst development of the embryo cleavage stage, fragmentation and uniformity of blastomeres was evaluated.

RESULTS

There were significant differences in the blastocyst development rate between > or =7 cells and < or=6 cells (68.8% vs. 30.7%), <50% fragmentation and > or =50% fragmentation (51.9% vs. 25.7%), and evenly sized blastomeres and unevenly sized blastomeres (48.7% vs. 30.1%) on day 3. The new grading system defined by these 3 parameters showed a preferable correlation to the pregnancy rate.

CONCLUSIONS

The new grading system specific for day 3 embryos is useful for the selection of good quality embryos and may improve the pregnancy rate.

Guidelines for the number of embryos to transfer following in vitro fertilization

OBJECTIVE

To review the effect of the number of embryos transferred on the outcome of in vitro fertilization (IVF), to provide guidelines on the number of embryos to transfer in IVF-embryo transfer (ET) in order to optimize healthy live births and minimize multiple pregnancies.

OPTIONS

Rates of live birth, clinical pregnancy, and multiple pregnancy or birth by number of embryos transferred are compared.

OUTCOMES

Clinical pregnancy, multiple pregnancy, and live birth rates.

EVIDENCE

The Cochrane Library and MEDLINE were searched for English language articles from 1990 to April 2006. Search terms included embryo transfer (ET), assisted reproduction, in vitro fertilization (IVF), ntracytoplasmic sperm injection (ICSI), multiple pregnancy, and multiple gestation. Additional references were identified through hand searches of bibliographies of identified articles.

VALUES

Available evidence was reviewed by the Reproductive Endocrinology and Infertility Committee and the Maternal-Fetal Medicine Committee of the Society of Obstetricians and Gynaecologists of Canada and the Board of the Canadian Fertility and Andrology Society, and was qualified using the Evaluation of Evidence Guidelines developed by the Canadian Task Force on the Periodic Health Exam.

BENEFITS, HARMS, AND COSTS

This guideline is intended to minimize the occurrence of multifetal gestation, particularly high-order multiples (HOM), while maintaining acceptable overall pregnancy and live birth rates following IVF-ET.

[How to improve assisted reproductive techniques results? Biological aspects]

In spite of recent improvements in IVF, pregnancy rates remained dramatically low. Better criteria are therefore necessary to establish the viability of a transferable top quality embryo. Observation of both pronuclei patterns at the zygote stage and early cleavage appears to offer an additional prognostic tool, correlating with chromosomal status and IVF outcome. Developmental ability and morphological evaluation of the embryo on days 2-3 remains the most used and valid method of selection, even though it is not sufficient to select embryos with the higher implantation potential. Blastocyst culture is another possible strategy for selecting the ideal embryo with theoretical, reduced risk of aneuploidies, though not all major chromosomal aberrations are excluded by prolonged in-vitro-culture. Concerning micro-manipulation of embryo such as hatching or cleaning or cytoplasm transfer, only controversial data are still available. In the field of ART, recent meta-analysis could not conclude to a positive effect concerning hatching, blastocyst culture or systematic PGD-AS (preimplantation genetic diagnosis with aneuploidy screening). Beside the technological aspect, Quality Management System is of great importance. Staff development and monitoring of staff performance in the IVF laboratory has to be considered in the next future.

Addressing the growing problem of multiple gestations created by assisted reproductive therapies

Iatrogenic multiple pregnancy is the most significant complication of assisted reproductive technology (ART). Approximately half of all children born subsequent to ART result from a plural gestation. Furthermore, the majority of triplets and higher order births are the product of ART. The risks for multiple pregnancy vary with practice patterns and the techniques used to achieve pregnancy. Recognizing the potential for serious morbidity associated with multiple pregnancies, infertility specialists have developed strategies to reduce the complication of multiple pregnancies while maintaining acceptable pregnancy rates. Implementation of these refined practices has led to a reduction in the incidence of higher order multiple births, although the incidence of twins has yet to be minimized. Further reduction in the incidence of multiple births after ART necessitates a redefinition of success to emphasize the healthy singleton birth rate, rather than crude pregnancy rates.