Is there any benefit from the culture of a single oocyte to a blastocyst-stage embryo in unstimulated cycles?

Trade-off between double cleavage-stage embryos transfer and single blastocyst-stage embryo transfer in patients with few good quality embryos in antagonist cycles: a retrospective study using a propensity score matching analysis

OBJECTIVE

This study aimed to compare the per OPU clinical outcomes for transfer of Day 3 double cleavage-stage embryos (DET) and Day 5 single blastocyst-stage (SBT) in patients with five or fewer good quality embryos on day 3 per occyte pick-up cycle (OPU) in antagonist cycles with consideration of blastocyst formation failure.

METHODS

This was a retrospective, observational cohort study of 2,116 cases of OPU treated with antagonist protocol in the affiliated Chenggong Hospital of Xiamen University between January 2013 and December 2020. DET was performed in 1,811cycles and SBT was performed in 305 cycles. The DET group was matched to the SBT group by propensity score (PS) matching according to multiple maternal baseline covariates. After PS matching, there were 303 ET cycles in each group. The primary outcomes were the cumulative live birth rate (CLBR), cumulative multiple pregnancy rate(CMPR)per OPU and the number of ET to achieve live birth per OPU. Secondary outcomes were the percentage of clinical pregnancy(CPR), live birth rate(LBR), multiple pregnancy rate(MPR).

RESULTS

Following PS mating, the CLBR was slightly higher (48.8% versus 40.3% ; P = 0.041) and the CMPR was significantly higher in the DET group compared to SBT group(44.2% versus 7.9%, P < 0.001). The CPR, LBR and MPR per fresh transfer were higher in DET group compared to SBT group(50.2% versus 28.7%; 41.3% versus 21.5%;29.6% versus 0%, P < 0.001). The number of ET to achieve live birth per OPU in SBT group was obiviously more than in DET group(1.48 ± 0.578 versus 1.22 ± 0.557 ,P < 0.001).

CONCLUSION

With a marginal difference cumulative live birth rate, the lower live birth rate per fresh transfer and higher number of ET per OPU in the SBT group suggested that it might take longer time to achieve a live birth with single blastocyst strategy. A trade-off decision should be made between efficiency and safety.

No difference in cumulative live birth rates between cleavage versus blastocyst transfer in patients with four or fewer zygotes: results from a retrospective study

STUDY QUESTION

Is the cumulative live birth rate (CLBR) per oocyte collection cycle (OCC) comparable after cleavage-stage or blastocyst-stage transfer in combination with supernumerary blastocyst vitrification on Day 5 (D5) in patients with four or fewer zygotes on Day 1?

SUMMARY ANSWER

The CLBR in a fresh blastocyst-transfer or cleavage-stage transfer policy followed by vitrification on D5 is comparable in patients with four or fewer zygotes.

WHAT IS KNOWN ALREADY

Blastocyst transfer enhances the self-selection of the embryo and shortens the time to pregnancy in patients with normal or high ovarian response. Whether these advantages are also present in patients with a low ovarian response and/or a limited number of available zygotes is a continuous debate.

STUDY DESIGN SIZE DURATION

This was a retrospective, observational cohort study of 2359 consecutive OCCs between January 2014 and December 2018. According to a shift in transfer policy in our center, 571 OCCs had been scheduled for a fresh transfer on Day 3 (D3) and 1788 on D5. The D5 group was matched to the D3 group by propensity score (PS) matching according to multiple maternal baseline covariates. After PS matching, there were 571 OCCs in each group.

PARTICIPANTS/MATERIALS SETTING METHODS

OCCs scheduled for a D3 transfer (n = 571) or for a D5 transfer (n = 1788) were matched by PS matching in a 1:1 ratio accounting for potential confounding factors associated with CLBR. The model included patient characteristics, such as maternal age and cycle rank, as well as treatment characteristics such as GnRH analog regimen and ovarian response. Embryological variables included the number of zygotes and the number of 6- to 7- and 8-cell embryos on D3. The delivery outcomes of the fresh treatment cycle and the consecutive vitrified-warmed embryo transfers were analyzed up to the first live birth. The primary endpoint of this study was CLBR per OCC. Secondary outcomes were live birth rate per fresh transfer and embryo implantation rate per transferred embryo.

MAIN RESULTS AND THE ROLE OF CHANCE

The CLBR per OCC was comparable between the D5 and D3 groups (16.8% versus 17.7%, respectively, P = 0.600). Live birth rates per OCC did not differ between a cleavage-stage transfer and blastocyst-stage transfer policy (15.2% versus 12.4%, respectively, P = 0.160). In the D5 group, 201 cycles did not result in a blastocyst to perform an embryo transfer or cryopreservation; in the D3 group, only 59 cycles did not have an embryo transfer because of poor embryo quality (35.2% versus 10.3%, respectively; P < 0.001). A significantly higher number of fresh double embryo transfers were performed in the D3 group compared to D5 (23.8% versus 7.0%, respectively, P < 0.001).

LIMITATIONS REASONS FOR CAUTION

Although adjusted for important confounders in the PS matching, BMI and embryo quality of the transferred embryo(s) were not taken into account. This study is limited by its retrospective design and is a single-center study, which may limit the generalizability of our findings.

WIDER IMPLICATIONS OF THE FINDINGS

The CLBR in a fresh blastocyst-transfer or cleavage-stage transfer policy followed by vitrification on D5 is comparable. A fresh embryo transfer on D3 can still be considered in patients with a poor ovarian response and/or limited number of zygotes when combined with blastocyst vitrification without impacting the overall CLBR of the cycle.

STUDY FUNDING/COMPETING INTERESTS

No external funding was obtained for this study. There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

This retrospective study was approved by the local ethical committee at Ghent University Hospital (B 670201731234).

A stepwise approach to move from a cleavage-stage to a blastocyst-stage transfer policy for all patients in the IVF clinic

STUDY QUESTION

Is a stepwise change management approach an efficacious method to move from a Day 3 transfer policy to a Day 5 transfer policy for all patients in an IVF program?

SUMMARY ANSWER

A stepwise change from a Day 3 to a Day 5 transfer policy maintained the live birth rates per oocyte collection cycle (OCC) of the IVF program, with increased single embryo transfer (SET) and reduction of twin pregnancies.

WHAT IS KNOWN ALREADY

Evidence has shown that the probability of a live birth following IVF with a fresh embryo transfer (ET) is significantly higher after blastocyst-stage transfer than after cleavage-stage transfer. Blastocyst culture and transfer are usually performed in cases of good prognosis patients but many centers keep transferring cleavage-stage embryos for most of their patients because of the higher transfer cancelation rate in a blastocyst transfer policy.

STUDY DESIGN, SIZE, DURATION

In January 2012, a Day 5 embryo culture and blastocyst transfer policy including vitrification of supernumerary Day 5 blastocysts were implemented in a stepwise approach. The retrospective descriptive single-center analysis involving a preintervention phase consisted of Day 3 ETs and Day 3 slow freezing from 2010 until 2012. The postintervention phase involved a 6-year period from 2012 until 2017 in which three consecutive changes in the transfer policy were made, each over a 2-year period, based on the number of zygotes on Day 1. The primary outcome was live birth delivery rate per OCC during the stepwise change.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All patients with at least one zygote available on Day 1 were scheduled for a fresh transfer, either on Day 3 or 5. Cycles with preimplantation genetic testing, freeze-all and oocyte donation cycles and cycles with a Day 2 transfer in the preintervention period were excluded. In the preintervention group, all cycles were scheduled for Day 3 transfer (n = 671 OCC) and slow freezing of the remaining Day 3 embryos. In the postintervention period, three periods were analyzed: period 1 (n = 1510 OCC; 1–9 zygotes: Day 3 transfer and >9 zygotes: Day 5 transfer); period 2 (n = 1456 OCC; 1–4 zygotes: Day 3 transfer and >4 zygotes: Day 5 transfer) and period 3 (n = 1764 OCC; Day 5 transfer). All remaining embryos underwent extend culture and were vitrified on Day 5, if developed to at least an early blastocyst. Data were analyzed using a mixed regression model with patient as a random factor.

MAIN RESULTS AND THE ROLE OF CHANCE

In the preintervention group, all OCC were scheduled for a Day 3 transfer. In period 1, period 2 and period 3, 20.9%, 61.5% and 100% of the OCCs were scheduled for a Day 5 transfer, respectively. More transfers per OCC were canceled in the postintervention period 2 and period 3 compared to the preintervention period (5.3% and 18.7% versus 3.4%, respectively; P < 0.0001). The mean number of embryos used per transfer decreased gradually after the introduction of the Day 5 transfer policy, from 1.62 ± 0.65 in the preintervention group to 1.12 ± 0.61 in period 3 (P < 0.0001). The percentage of SET cycles increased from 48.4% in the preintervention group to 54.6%, 73.8% and 87.8% in period 1, period 2 and period 3, respectively (P < 0.0001). The mean number of cryopreserved surplus embryos was significantly lower in period 3 compared to the preintervention group (1.29 ± 1.97 versus 1.78 ± 2.80; P < 0.0001).

Pregnancy and live birth delivery rate per fresh transfer, respectively, were significantly lower in the preintervention group (26.7% and 19.1%) as compared to period 3 (39.3% and 24.2%) (P < 0.0001). Twin pregnancy rate decreased gradually from 11.0% to 8.2%, 5.7% and 2.5% in the preintervention group, period 1, period 2 and period 3, respectively (P < 0.0001). Live birth rate and cumulative live birth delivery rates per OCC were significantly higher in group 2 compared to the preintervention period (25.6% and 35.8% versus 18.5% and 25.9%, respectively). Similar live birth and cumulative live birth delivery rates per OCC were achieved between the preintervention period and period 3 (18.5% and 25.6% versus 19.7% and 24.9%; respectively).

LIMITATIONS, REASONS FOR CAUTION

The primary limitation is the retrospective design of the study. The allocation of the cycles was done by the number of zygotes available without taking into account both embryological and clinical prognostic factors. Furthermore, the analysis was restricted to cycles where the standard transfer policy was followed. Embryos which were in the morula or compaction stage were not vitrified or cultured to Day 6, which could have contributed to the slight, not statistically significant, drop in live birth rate per OCC in group 3.

WIDER IMPLICATIONS OF THE FINDINGS

Live birth and cumulative live birth delivery rate per OCC in an unselected patient population is maintained in a Day 5 transfer policy compared to a Day 3 transfer policy. Additionally, a significantly reduction in twin pregnancy rate and a significant increase in SET were observed in a Day 5 transfer policy. For centers wanting to make the step from Day 3 to Day 5, this study provides a practical stepwise change management approach.

STUDY FUNDING/COMPETING INTEREST(S)

None.

TRIAL REGISTRATION NUMBER

None.

Endometrial injury, the quality of embryos, and blastocyst transfer are the most important prognostic factors for in vitro fertilization success after previous repeated unsuccessful attempts

Purpose

The purpose of this study was to find out the most important prognostic factors for achieving a pregnancy after in vitro fertilization (IVF) in women with history of repeated unsuccessful IVF attempts.

Methods

We analyzed factors affecting pregnancy rate in a retrospective study including 429 IVF/ICSI cycles performed in women younger than 40 years with at least three previous consecutive failed IVF/ICSI attempts.

Results

Clinical pregnancy was observed in 140/429 (32.6%) cycles. Clinical pregnancy rate (CPR) was significantly higher in cycles with LEI compared to cycles without LEI before embryo transfer (44.4 vs 26.54%, p = 0.007). The CPR was also higher in cycles with day 5 blastocyst- compared with day 3 cleavage-stage embryo transfers (45.51 vs 26.54%, p < 0.001). In multivariate logistic regression model, only transfer of at least one good quality embryo (OR = 4.32, 95% CI 2.41–7.73), local endometrial injury (OR = 1.73, 95% CI 1.02–2.92), and transfer on day 5 (OR = 3.02, 95% CI 1.53–5.94) remained important independent prognostic factors for clinical pregnancy.

Conclusions

These results suggest that hysteroscopy with local injury to the endometrium prior to ovarian stimulation for IVF/ICSI can improve implantation and pregnancy rates in women experiencing recurrent IVF failure. However, large studies are needed to confirm these findings.

Increased Krüppel-like factor 12 in recurrent implantation failure impairs endometrial decidualization by repressing Nur77 expression

BACKGROUND

Decidualization is a prerequisite for successful implantation and the establishment of pregnancy. A critical role of impaired decidualization in subfertility has been established. In human endometrial stromal cells (hESCs), Krüppel-like factor 12 (KLF12) and Nur77 are novel regulators of decidualization. We investigated whether KLF12 impaired the decidualization of hESCs in recurrent implantation failure (RIF) patients.

METHODS

Endometrial tissues and hESCs were collected from RIF patients (n = 34) and fertile controls (n = 30) for in vitro analysis. Primary hESCs isolated from RIF endometrial tissues were used to evaluate the biological functions of KLF12 and Nur77. In addition, their molecular mechanisms were investigated by adenovirus-mediated overexpression. Gene expression regulation was examined by real-time-quantitative PCR (qRT-PCR), immunostaining and luciferase reporter assay. Further, blastocyst-like spheroid (BLS) and blastocyst implantation models were performed to examine the roles of KLF12 and Nur77 during embryo expansion on hESCs.

RESULTS

hESCs from the RIF patients showed a poor decidual response, mainly characterized by decreased decidual prolactin (dPRL) secretion, impaired transformation and limited BLS expansion. In addition, KLF12 expression was increased in endometrial tissues from the RIF patients compared with those from the fertile controls, especially in stromal compartments. The opposite results were observed for Nur77 expression in these tissues. KLF12 repressed hESC decidualization by decreasing Nur77 expression. Mechanistically, KLF12 bound to a conserved site in the Nur77 promoter region. Nur77 overexpression significantly reversed the KLF12-mediated repression of dPRL expression, decidual transformation and BLS/blastocyst expansion.

CONCLUSIONS

KLF12 impairs endometrial decidualization by transcriptionally repressing Nur77, and Nur77 overexpression reverses the poor decidual response of hESCs in RIF patients.

Decreased expression of NR4A nuclear receptors in adenomyosis impairs endometrial decidualization

STUDY QUESTION

How do NR4A receptors drive decidualization of human endometrial stromal cells (hESCs)?

SUMMARY ANSWER

NR4A receptors modulate endometrial decidualization by transcriptional activation of FOXO1A, and in adenomyosis patients, the reduced expression of NR4A receptors in the eutopic endometrium may represent a novel mechanism to explain impaired decidualization and subfertility.

WHAT IS KNOWN ALREADY

A close relationship between impaired decidualization and subfertility has been established. In human endometrial stromal cells, orphan nuclear receptor NR4A is a novel regulator of decidualization.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

Eutopic endometrial tissues and hESCs from fertile controls (n = 56) and adenomyosis patients (n = 27) were collected for in vitro analysis. Primary hESCs isolated from eutopic endometrial tissues were used to evaluate the biological function of NR4A receptors. Adenovirus-mediated overexpression of NR4A and small interfering RNAs targeting NR4A, and FOXO1A were used to investigate the molecular mechanisms. Gene expression regulation was examined by real-time-quantitative PCR, immunostaining, and luciferase reporter assay. Artificial decidualization assay was performed to investigate the role of NR4A1 during decidualization in vivo.

MAIN RESULTS AND THE ROLE OF CHANCE

NR4A modulates the decidualization of hESCs by upregulating prolactin (PRL) and insulin-like growth factor binding protein-1 (IGFBP-1) expression and transformation in vitro. Loss of uterine Nr4a1 results in female subfertility due to impaired decidualization. Mechanistically, NR4A binds to the nerve growth factor 1B (NGFI-B) -responsive element (NBRE) (-843 to -813) within the FOXO1A promoter region and regulates FOXO1A expression. Loss of FOXO1A significantly inhibits PRL and IGFBP-1 expression, as induced by NR4A. Moreover, the expression of NR4A and FOXO1A was lower in adenomyosis endometrial tissues compared to fertile controls, especially in stroma compartments. Ectopic NR4A expression rescued PRL and IGFBP-1 expression in adenomyotic hESCs to near-normal levels. Furthermore, PI3K/AKT signaling pathway involved in inducing NR4A expression under decidualization stimuli in hESCs and the level of p(Ser473)-AKT was significantly higher in stroma in endometrium from patients with adenomyosis.

LIMITATIONS, REASONS FOR CAUTION

This is an in vitro study with a small sample size, utilizing stromal cell cultures from endometrial tissues of adenomyosis patients. Furthermore, results obtained should also be confirmed in a larger data set and with adenomyosis mouse models in vivo.

WIDER IMPLICATIONS OF THE FINDINGS

Identification of a positive agonist of NR4A receptors will be critical for the improved treatment of patients with conditions of insufficient decidualization-associated infertility, such as adenomyosis and endometriosis.

LARGE SCALE DATA

N/A.

STUDY FUNDING AND COMPETING INTERESTS

This study was supported by the National Natural Science Foundation of China (81170570, G.J.Y. 81370683, G.J.Y. 81501251, Y.J. 31571189, H.X.S. and 81571402, G.J.Y.), and a special grant for clinical medicine science of Jiangsu Province (BL2014003, H.X.S.). The authors have no conflicts of interest to declare.

Embryo culture and selection: morphological criteria

In this chapter, we have outlined the various morphological criteria for selection of the best embryo at each important milestone encountered in the progress from the oocyte to the blastocyst. As Gerris et al. stated, a combination of one, two, or even three selection points should lead to a more accurate selection of the best embryo, as no one criterion is better than the other. An embryo that fails to meet the entire set of selection criteria must be avoided as culture cannot correct an impaired embryo.

Seminal plasma enhances and accelerates progesterone-induced decidualisation of human endometrial stromal cells

In preparation for embryo implantation, endometrial stromal cells (ESC) undergo differentiation, termed decidualisation. Enhancing endometrial decidualisation may overcome reduced endometrial receptivity, a major limiting factor in natural and assisted reproduction. To determine whether seminal plasma (SP) influences decidualisation, primary human ESC were treated with progesterone (P4, 50 ng mL(-1)) in the presence or absence of dialysed SP (0.5%) for 24 h or for up to 27 days to investigate immediate early effects or the effects of prolonged exposure, respectively. Combined SP and P4 treatment induced ESC morphological differentiation. Relative to control, P4 alone, and SP alone combined treatment with SP and P4 for 27 days significantly upregulated mRNA levels of the decidua-specific markers prolactin (PRL) and insulin-like growth factor binding protein 1 (IGFBP1). Consistently, PRL protein secretion was significantly increased over the course of 27 days combined SP and P4 treatment relative to control, P4 alone and SP alone. Likewise, IGFBP1 secretion was significantly greater relative to control and P4 alone over the course of 27 days. Thus, SP enhances and accelerates P4-mediated decidualisation of human ESC and may enhance endometrial receptivity.

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.

Embryo transfer and luteal support in natural cycles

Embryo transfer policy and luteal supplementation was reviewed, comparing literature data and the results from the Maribor IVF Centre. A retrospective analysis of 1024 cycles in patients undergoing IVF, intracytoplasmic sperm injection (ICSI) or testicular sperm aspiration in unstimulated cycles was carried out using four different approaches for cycle monitoring. This showed that the most successful protocol for monitoring was administration of human chorionic gonadotrophin (HCG) when serum oestradiol was >0.49 nmol/l and follicle diameter was at least 15 mm. The implantation rate per transferred embryo was higher when a blastocyst was transferred (42.8%) rather than a day-2 embryo (23.5%) in the same monitoring protocol. Analysis of the influence of patient age on the success of oocyte retrieval, oocyte fertilization, embryo transfer rate and delivery rate demonstrates that patient age does not influence the rate of positive oocyte retrieval or fertilization rate as much as it influences pregnancy rate per embryo transfer. The delivery rate per cycle was dramatically influenced by age in patients over 38 years. There is no clear evidence in the literature as to whether luteal phase support is necessary in natural cycles for IVF/ICSI. Comparing the data, a higher pregnancy rate was observed if HCG was administered after embryo transfer.

The human endometrium as a fertility-determining factor

Intensive research work has been performed to better understand the regulation of the endometrium and its clinical implications to improve implantation. Although many proteins and molecules may influence endometrial development, their co-ordinated contribution to the implantation process is still poorly understood and a translation into clinical use has not sufficiently been performed. Clinical evaluation of the endometrium by ultrasound and other techniques, like endometrial biopsy and analysis of uterine secretions, has been intensively studied and therapeutic options to improve endometrial function have been suggested and tested. Systemic treatment with heparin, aspirin or corticosteroids did not result in improved implantation rates. Gene therapy and cervical treatment, e.g. with seminal plasma, are still in the phase of clinical research. Therefore, this review focuses on different aspects of endometrial research, which all contribute to the diagnosis, evaluation and therapy of endometrial function and dysfunction. First, the endometrial development towards a receptive milieu is described. Second, the actual clinical evaluation of endometrial receptivity, possible therapeutic strategies and in particular, the evaluation of endometrial function in the non-natural situation of hormonal stimulation is critically evaluated. In conclusion, the endometrium shall be considered as an important fertility-determining factor and therapeutic options should be developed in near future.

Pregnancy rate, multiple pregnancy rate, and embryo quality: Clues for single blastocyst transfer from double blastocyst transfer in an unselected population

Objective:  Minimizing multiple pregnancy is a priority in assisted reproduction. As implantation rates are critical to success and reduce multiple pregnancy, we investigated whether blastocyst grade determined implantation rate following double blastocyst transfer in unselected cases. Materials and Methods:  We studied 69 three-cleavage stage embryo transfers and 64 two-blastocyst transfers. Two blastocysts, or one when two blastocysts were not available, were transfered after evaluating the grade of blastocysts. The difference in pregnancy and implantation rates to patient age, the number of retrieved oocytes and grade of blastocysts were analyzed. Results:  Blastocyst and grade 3AA rates per fertilized egg were 50.3% and 26.0%, respectively. Following two-blastocyst transfer, pregnancy rate per transfer, implantation rate per embryo, and multiple pregnancy rate per pregnancy were 39.1%, 26.5%, and 24.0%, respectively. Two-blastocyst transfer achieved implantation more often than three-cleavage-stage embryo transfer, but did not reduce multiple pregnancy. Pregnancy, implantation, and multiple pregnancy rates did not reflect maternal age. Higher pregnancy and implantation rates per transfer were attained for with six or more oocytes retrieved or transfer of two-blastocyst graded 3AA or higher especially when two or more blastocysts graded 3AA or higher are available, but the latter showed a high multiple pregnancy rate (38.5%). Conclusions:  Single embryo transfer could be carried out when two or more blastocysts of grade 3AA or higher have been developed. (Reprod Med Biol 2005; 4: 153-160).

Controlled natural cycle IVF with antagonist use and blastocyst transfer

A method of controlled natural cycle IVF (CONCIVF) was sought to provide simpler and shorter treatment without the risks of ovarian hyperstimulation syndrome and multiple pregnancies. A total of 138 couples with normal ovulation and normal sperm parameters, in whom the women were <40 years old, were the candidates for this study. Gonadotrophin-releasing hormone antagonist was used before human chorionic gonadotrophin (HCG) administration if LH increased to a concentration of 10 mIU/ml before HCG injection. Treatment was initiated at > or =16 mm follicular growth and at oestradiol concentrations > or =400 pmol/l with 5000 IU HCG induction. All the embryos were cultured to the blastocyst stage and transferred only if they reached early or advanced blastulation. A total of 126 patients underwent oocyte retrieval. In 102 cases, one oocyte was retrieved; 95% of the oocytes fertilized, 99% cleaved and 47.9% achieved the blastocyst stage. The implantation rate per blastocyst transfer was 53.3% and the live-birth rate per embryo transfer was 40%. Therefore, CONCIVF with blastocyst transfer gives acceptable blastocyst development and implantation rates without the long- or short-term side effects of ovulation induction.

Developmental capacity of different morphological types of day 5 human morulae and blastocysts

After prolonged culture of human embryos, the expanded blastocysts with oval inner cell mass (ICM) and cohesive trophectoderm (TE) are preferably selected for transfer. In cycles with poor embryonic development, the selection has to be done from among suboptimal blastocysts for which no grading system exists. In this study, 1396 transferred blastocysts and morulae were classified into eight morphologic categories. The B1 category constituted the optimal blastocysts. The other categories were characterized by different deviations from optimal blastocysts: cytoplasmic fragments and necrosis in TE (B2), unexpanded blastocoele (B3), non-compact or small ICM (B4), fragments in TE and ICM (B5), up to 20% excluded blastomeres (B6), necrotic TE and ICM (B7), and more than 20% excluded cells from blastocysts (B8). The live birth rate was calculated from blastocysts with known outcome after transfer (88.9% transferred blastocysts). The birth rate declined from B1 to B8 by the same order and was: 45.2, 32.8, 26.9, 23, 17.7, 16.7, 7.7 and 1.2% respectively. Normal ICM was recognized as the most important parameter for implantation. There was a strong relation between such ordered morphology categories and implantation capacity (P < 0.0001). Such a grading system is helpful in selecting the best of all available day-5 embryos for transfer.

Measurement of perifollicular blood flow of the dominant preovulatory follicle using three-dimensional power Doppler

OBJECTIVE

To establish whether we might predict the outcome of unstimulated in-vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles with quantitative indices of perifollicular blood flow assessed with three-dimensional (3D) reconstruction of power Doppler images.

METHODS

This prospective study included an analysis of 52 unstimulated cycles. Color and power Doppler ultrasound examinations of a single dominant preovulatory follicle were performed on the day of oocyte pick-up. With 3D reconstruction and processing, quantitative indices were obtained i.e. the percentage of volume showing a flow signal (VFS) inside a 5-mm capsule of perifollicular tissue and the percentage of VFS of each of the three largest vessels in this capsule. These indices as well as pulsed Doppler indices were compared between the groups of cycles with different outcomes using a one-way ANOVA test.

RESULTS

In nine cycles no oocyte was retrieved (Group A), in seven cycles no fertilization occurred (Group B) and in 30 cycles no implantation occurred (Group C). Six cycles resulted in pregnancy (Group D). There were no statistically significant differences in pulsed and power Doppler indices between these groups. However, the percentage of VFS in the capsule was higher than average in cycles with implantation (19.22 +/- 16.82 vs. 12.42 +/- 8.89, NS) and the percentage of VFS in the main vessel exhibited lower than average values in cycles with implantation (20.66 +/- 10.05 vs. 39.84 +/- 20.15), but only reached borderline statistical significance (F = 2.457, P = 0.074).

CONCLUSION

It can be hypothesized that the follicles containing oocytes able to produce a pregnancy have a distinctive and more uniform perifollicular vascular network.

Pronuclear scoring as a predictor of embryo development

Many strategies have been proposed for the selection of viable embryos for transfer in human assisted reproduction. These have included morphological scoring criteria for day 1, 2, 3 and 5 embryos or combinations of these. Other strategies have used predictors such as timing of certain key events, as with early cleavage to the 2-cell, development to the 8-cell stage or patterns of fragmentation. All have shown some correlations with implantation. However, the overall success of these methods is still limited, with over 50% of all transferred embryos failing to implant. The use of pronuclear oocyte morphology has shown correlations with implantation and development to the blastocyst stage. The key aspects of pronuclear scoring, namely the presence of a cytoplasmic halo, the orientation of the nuclei in relation to the polar bodies and the size, number and pattern of distribution of nucleolar precursor bodies (NPB) in the nuclei were related to day 2,3 and 5 development, rate of development and day 3 and 5 morphology in a retrospective study. The pattern of the NPB or Z-score and the presence/absence of a halo had a significant effect on the rate of development on day 3 and day 5 and on the overall embryo morphology score. Low Z-score resulted in slow development, poor blastocyst formation and low morphology scores. The absence of a halo also resulted in slow and poor development, poor morphology, increased fragmentation and increased numbers of poor Z-scored embryos. The use of PN scoring can help predict embryos that have poor developmental potential, aid in early selection and may indicate the health of the oocyte.

Comparable effectiveness using flexible single-dose GnRH antagonist (cetrorelix) and single-dose long GnRH agonist (goserelin) protocol for IVF cycles – a prospective, randomized study

This prospective randomized study compared the effectiveness of a flexible single-dose gonadotrophin-releasing hormone (GnRH) antagonist (cetrorelix) and a single-dose long GnRH agonist (goserelin) protocol for ovarian stimulation in IVF/intracytoplasmic sperm injection (ICSI) cycles. All patients from the waiting list were successively included in the study, pre-programmed with an oral contraceptive, and randomized into goserelin and cetrorelix groups. Depending on the date on which their menstrual period started, patients took oral contraceptives for one or two cycles. Ultimately, 236 patients in the first group received a single dose of depot preparation of goserelin and 224 patients received a single 3 mg dose of cetrorelix in the late follicular phase, when the mean follicle diameter exceeded 12 mm. The mean number of ampoules of FSH and the duration of stimulation was statistically significantly lower in the cetrorelix group than in the goserelin group (25.9 versus 34.5, and 9.6 versus 12.2 days, P < 0.01). The mean number of oocytes retrieved was similar (6.7 +/- 4.5 versus 7.2 +/- 4.6, NS). Similar results were observed in fertilization rates, blastulation rates and blastocyst transfer rates in both groups. Clinical pregnancy and delivery rates per cycle were higher in the goserelin group (34.3 and 30.1%) than in the cetrorelix group (31.9 and 28.3%), but the differences were not statistically significant. The flexible single-dose GnRH antagonist protocol is an advantageous alternative to the long GnRH agonist protocol, with similar efficacy, shorter duration, a significant reduction in the number of FSH ampoules used and without the menopause-like effects of the GnRH antagonist.

Blastocyst culture: facts and fiction

The use of sequential media has made extended culture and transfer of blastocysts feasible for human IVF. Embryo transfer on day 5 has been claimed to result in higher implantation rates than transfer on day 3, on the basis of retrospective comparative studies. This is not supported convincingly, however, in randomized controlled trials published to date. Blastocyst culture imposes additional requirements in terms of personnel, equipment, education and cost and is associated with a greater incidence of monozygotic twinning and cycle cancellation rate than in the case of day 3 culture. In order for day 5 transfer to replace day 3 transfer, a convincing comparison between the two methods should therefore demonstrate the superiority of blastocyst transfer. There is still a need for properly designed randomized controlled trials to compare day 3 with day 5 transfer which will also address the effectiveness of a single blastocyst replacement in reducing the incidence of multiple pregnancies as well as the value of blastocyst cryopreservation.