The limited importance of pronuclear scoring of human zygotes

BACKGROUND: Several studies have shown a correlation between the pronuclear morphology score (PNMS) and subsequent embryo development and implantation. Embryos with poor pronuclear score, elsewhere referred to as Z3 and Z4, are often not transferred or cryopreserved because it is believed that they have poor pregnancy potential. The objective of this study is to report our data on the use of the pronuclear score and its effect on pregnancy outcome. METHODS: Retrospective analysis of IVF/ICSI-embryo transfer cycles completed over the course of 1 year (n = 334). Comparisons were made only in those groups of patients in whom cohorts of similarly scored PNMS embryos were transferred. The proportion of such homologous cohorts was 104/334 (31%). All other replacements were excluded from final analysis as they were dissimilar as far as PNMS is concerned. Pregnancy outcomes were evaluated. RESULTS: The incidence of live birth resulting from the transfer of single pronuclear score homologous embryo types was 56 (14/25), 41 (13/32), 54 (23/43) and 0% (0/4) for PNMS scores 1, 2, 3 and 4, respectively. There was no correlation between PNMS category of the embryos transferred and live birth rates (P = 0.139). CONCLUSIONS: PNMSs of 1, 2 or 3 do not correlate with live birth rates when assessing unique PNMS embryo transfers. In particular, previously considered poor (type 3) embryos can result in pregnancy with normal live birth rates. Whether type 4 embryos are compatible with normal development remains to be shown.     

Day 3 embryo selection by metabolomic profiling of culture medium with near-infrared spectroscopy as an adjunct to morphology: a randomized controlled trial

STUDY QUESTION: Is the selection of a single Day 3 embryo by metabolomic profiling of culture medium with near-infrared (NIR) spectroscopy as an adjunct to morphology able to improve live birth rates in IVF, compared with embryo selection by morphology alone? SUMMARY ANSWER: The live birth rate after embryo selection by NIR spectroscopy and morphology is not significantly different compared with the live birth rate after embryos were selected by morphology alone. WHAT IS KNOWN ALREADY: The elevated incidence of pregnancy and neonatal problems associated with a high-twinning rate after IVF can only be successfully reduced by the transfer of one embryo. Current embryo assessment methods are unable to accurately predict the reproductive potential of an individual embryo. Today, a number of techniques are said to be more accurate at selecting the best embryo. One of these new technologies is metabolomic profiling of spent embryo culture media with the use of NIR spectroscopy. STUDY DESIGN, SIZE AND DURATION: A double-blind, randomized controlled trial was conducted between 2009 and 2011, and included 417 couples undergoing IVF with a single embryo transfer. Randomization was performed centrally just before Ovum Pick-Up (OPU), using a computerized randomization program. Both patient and physician were unaware of the treatment allocation. To ensure blinding, the allocations were placed in consecutively numbered, opaque envelopes. Patients were randomized (1:1) into either the control group (embryo selection by morphology only) or the treatment group (embryo selection by morphology plus NIR spectroscopy of embryo culture medium). PARTICIPANTS/MATERIALS, SETTING AND METHODS: At OPU, 208 patients were randomized to the morphology only group and 209 patients were randomized to the morphology plus viability score group. On Day 3, 163 patients in the control group and 146 patients in the treatment group met the inclusion criteria. The study was conducted in an academic hospital with IVF laboratory and three non-academic hospitals. MAIN RESULTS AND THE ROLE OF CHANCE: Patient demographics and baseline characteristics were distributed equally over the two groups, except for embryo fragmentation, which was significantly higher in the treatment group. In the intention to treat analysis, the live birth rates were 31.7 and 26.8% for the control group and the treatment group, respectively (relative risk 0.84; 95% confidence interval 0.63-1.14, P=0.27). In the per protocol analysis, the live birth rates were 31.3 and 29.5% for the control group and the treatment group, respectively (relative risk 0.94; 95% confidence interval 0.67-1.32, P=0.73). For the treatment group, the embryological technician's independent choice (by morphology) of which embryo to transfer was recorded 138 times. In 75.4% (104 of 138) of the transfers, the embryo with the best morphology did not have the highest viability score. The live birth rate of these 104 transferred embryos was 30.8%. LIMITATIONS, REASONS FOR CAUTION: A possible limitation of our study is the pre-selection of all embryos by morphology and dividing the cohort of available embryos into two groups: good quality embryos and poor quality embryos. As a consequence, we have probably selected for a better prognosis patient group. WIDER IMPLICATIONS OF THE FINDINGS: To avoid the use of incompetent embryo selection tools at the expense of the patient, an evidence-based proof of clinical usefulness is essential before the implementation of new diagnostic tools in IVF laboratories. TRIAL REGISTRATION NUMBERS: Dutch Trial Registry, registry number NTR1178.     

常规IVF受精失败补救ICSI后行冻融胚胎移植的临床价值

目的探讨冻融胚胎移植在常规体外受精(IVF)失败后补救卵胞浆内单精子注射(L-ICSI)中的应用价值。方法在12个常规体外受精失败周期中应用ICSI对未受精的MⅡ期卵子进行显微授精,将获得的优质胚胎进行冷冻,再择期行冻融胚胎移植。结果对93个未受精的MⅡ卵子接受L-ICSI,受精63枚,受精率为67.7%(63/93),异常受精3枚(2枚1PN,1枚3PN),57个正常受精卵发生卵裂,卵裂率为95.0%(57/60),优质胚胎率为43.9%(25/57),10例患者冷冻胚胎25枚,其中4例采用程序化冷冻,6例采用玻璃化冷冻。9个患者行冻融胚胎移植,共移植胚胎18枚(其中解冻后胚胎碎裂死亡5枚),其中1个周期因冻融后2个胚胎碎裂放弃移植,2例获得临床妊娠,1例分娩出正常婴儿,1例正在妊娠中,临床妊娠率为22.2%。结论 ICSI可使常规体外受精失败的卵子再受精,冻融胚胎移植可以解决胚胎与子宫内膜不同步的问题,获得相对满意的临床结局,具有一定的应用价值。     

The cumulative embryo score: a predictive embryo scoring technique to select the optimal number of embryos to transfer in an in-vitro fertilization and embryo transfer programme.

In order to achieve a clinical pregnancy rate higher than that achieved following initial adoption of in-vitro fertilization embryo transfers, more than one embryo is transferred. This has led to a substantial increase in unwanted multiple pregnancy rates with IVF as compared with natural conception. What is therefore required is a simple, clinically useful embryo scoring system, to reflect embryo developmental potential, which will enable the selection of the optimal number of embryos to transfer in order to achieve the maximum pregnancy rate with a low incidence of high order multiple pregnancies. We believe that the Cumulative Embryo Score (CES) achieves these aims. On the day of embryo transfer the grade of each embryo transferred was multiplied by the number of blastomeres to produce a score for each embryo, and summation of the scores obtained for all the embryos transferred gave the CES. The grouped pregnancy rates obtained rose as the CES increased to maximum of 42. A continued increase in the CES above 42 did not result in any further rise in the pregnancy rate. However, an analysis of all our IVF pregnancies showed that the multiple pregnancy rate continued to rise above a CES of 42. By restricting the CES per embryo transfer to 42, 78% of triplet pregnancies and 100% of the quadruplet IVF pregnancies could have been predicted and potentially avoided.     

The effects of co-culture with human fibroblasts on human embryo development in vitro and implantation

In a human in-vitro fertilization (IVF) programme, the effect of co- culture of embryos with human fibroblasts was evaluated with respect to pregnancy rate and embryo development. Patients were included in the study after giving informed written consent. The IVF treatments were randomly assigned by stratification of both age (<36 versus > or =36 years) and previous IVF attempts (yes versus no). After fertilization was established, the zygotes were transferred to a 4-well dish with or without fibroblasts and cultured for 2 days. On the third day after ovum pick-up (OPU), cell number and quality [5 (good) to 1 (poor)] of the embryos were scored and a maximum of three embryos was transferred. Supernumerary embryos of good quality were cryopreserved. The design of this study was a group sequential trial with the objective of detecting differences between pregnancy rates following IVF with conventional incubation or incubation in co-culture with fibroblasts. This design included one evaluation at half-way data collection. In the study, 148 patients had an OPU, of whom 77 were allocated to the co-culture group. There was no statistically significant difference in pregnancy rate, cell number and embryo quality between the two groups. The ongoing pregnancy rate per embryo transfer was 27% in co-culture and 30% in the conventional culture group. The implantation rates per transferred embryo were 17 and 18% respectively. Using a multivariate logistic regression model for the probability of ongoing pregnancies, the odds ratio of co-culture, adjusted for age and previous IVF attempts, was not statistically significant. In conclusion, co-culture with human fibroblasts does not contribute to an improvement of embryo quality nor to a higher pregnancy rate after IVF in an unselected group of patients.      

Number of embryos for transfer after IVF and ICSI: a Cochrane review

BACKGROUND: The most common complication of IVF is multiple pregnancy, which occurs in 25% of pregnancies following the transfer of two embryos. Single embryo transfer can minimize twin pregnancies but could also lower live birth rates. Our aim was to perform a systematic review of randomized trials to determine the effectiveness of single versus double embryo transfer. METHODS: Cochrane Collaboration review methods were followed. Randomized controlled trials comparing single and double embryo transfers were identified by searching Medline, EMBASE and the Cochrane register of controlled trials. Contents of specialist journals and proceedings from meetings of relevant societies were hand searched. Data were pooled with Rev Man software using the Peto-modified Mantel-Hanzel method. RESULTS: Pooled results from four trials indicate that although double embryo transfer leads to a higher live birth rate per woman [odds ratio (OR) 1.94, 95% confidence interval (CI) 1.47-2.55] in a fresh IVF cycle, comparable results are obtained by subsequent transfer of a frozen embryo (OR 1.19, 95% CI 0.87-1.62). The multiple pregnancy rate is significantly higher (OR 62.83, 95% CI 8.52-463.57) after double embryo transfer. CONCLUSIONS: Single embryo transfer significantly reduces the risk of multiple pregnancy, but also decreases the chance of live birth in a fresh IVF cycle. Subsequent replacement of a single frozen embryo achieves a live birth rate comparable with double embryo transfer.     

Fertilization and early embryology: Granulosa cell co-culture enhances human embryo development and pregnancy rate following in-vitro fertilization

A preliminary study and related clinical trial were performedto evaluate the effects of granulosa-lutein cell co-cultureon human embryo development and pregnancy rates for in-vitrofertilization (IVF). In the study, sibling two-pronuclear zygoteswere randomly allocated to culture with (co-culture) or without(control) autologous granulosalutein cells. After 24 h, embryoswere examined for blastomere number and degree of fragmentation.Co-culture had no effect on the average number of blastomeresper embryo at 24 h; however, fragmentation was significantlydecreased in co-cultured embryos (0.7 ± 0.1) comparedwith controls (1.3 ± 0.2; P < 0.05). In the subsequentclinical trial, all two-pronuclear zygotes were co-culturedfor 48 h prior to embryo transfer. The live birth rate per embryotransfer was 43.4% with an implantation rate per embryo of 17.6%.Of the untransferred embryos, 68% developed to the blastocyststage and were cryopreserved. We conclude that the simple systemof autologous granulosa-lutein cell co-culture improves embryodevelopment, implantation and subsequent pregnancy rates forIVF.     

The contribution of embryo cryopreservation to in-vitro fertilization/gamete intra-Fallopian transfer: 8 years experience

In this paper, the authors summarized their experience withembryo cryopreservation over an 8-year period. The results,therefore, reflect the long-term benefit of embryo cryo-preservationto the overall in-vitro fertilization/gamete intra-Fallopiantransfer (IVF/GIFT) programme and to the women who had embryoscryopreserved. The stable survival rate of thawed embryos andpregnancy rate, especially over the past 4 years, suggests thatthe results can reliably be used to evaluate the efficacy ofthe embryo cryopreservation programme. The ongoing pregnancyrate of frozen/thawed embryo transfer is 10.9%, comparable withthe ongoing pregnancy rate of fresh IVF/embryo transfer in ourunit over the same period. In addition to those factors knownto affect the pregnancy rate in fresh IVF/GIFT cycles, suchas age of the recipients and number of embryos transferred,the major factor affecting the efficacy of the cryopreservationprogramme is the number of oocytes retrieved in the initialstimulation cycle, and the number of embryos available for cryopreservation.The storage time of cryopreserved embryos will also have a significanteffect on the realization of the total potential of embryo cryopreservation.Overall the contribution of cryopreservation to our IVF/GIFTprogramme is substantial, increasing pregnancy rate by 4%, whilethe greater net benefit, of course, is for the women who hadembryos cryopreserved (pregnancy rate increased by 7%), especiallyfor those who returned for frozen/thawed embryo transfer cycles(pregnancy rate increased by 11%).     

Identification of viable embryos in IVF by non-invasive measurement of amino acid turnover

BACKGROUND: IVF is limited by low success rates and an unacceptably high multiple pregnancy rate. These outcomes would be improved significantly if a single embryo of high viability could be replaced in each treatment cycle, but widespread acceptance of such a policy is hindered by the lack of predictive factors for embryo selection. We have conducted a retrospective clinical study of a novel non-invasive method of embryo selection based on the depletion/appearance of amino acids in the culture medium. METHODS: Fifty-three cycles of IVF treatment using ICSI were studied. Embryos were cultured for 24 h in 4 microl drops of medium containing a physiological mixture of 18 amino acids. The spent medium was analysed for amino acid content by high performance liquid chromatography. RESULTS: The turnover of three amino acids, Asn, Gly and Leu, was significantly correlated with a clinical pregnancy and live birth. These correlations were independent of known predictors, such as female age, basal levels of FSH, embryo cell number and embryo morphological grade. CONCLUSIONS: Non-invasive assay of amino acid turnover has the potential to improve significantly the prospective selection of the most viable embryos, or single embryo, for replacement in an IVF cycle.     

Frozen embryo transfers: implications of clinical and embryological factors on the pregnancy outcome

BACKGROUND: Frozen embryo transfers are characterized by impaired pregnancy outcome and increased incidence of pregnancy loss as compared with fresh IVF/ICSI embryo transfers. In this study, we performed a retrospective analysis of clinical and embryological factors that potentially influence the outcome of frozen embryo transfer. METHODS: We reviewed the outcome of 1242 frozen embryo transfers with respect to the age of the woman, the method of fertilization, embryo quality before and after freezing and the number of embryos transferred. RESULTS AND CONCLUSIONS: The pregnancy (positive hCG) and clinical pregnancy rates were 25.8 and 21.1%, respectively. A total of 107 (33.3%) of the 321 pregnancies identified by a positive hCG test miscarried either before (18.4%) or after (15%) the clinical recognition of gestational sac(s). The delivery rate for the frozen embryo transfers analysed was 17.2%. Our data revealed that the delivery rate after frozen embryo transfer was dependent on both the woman's age and the quality of embryos transferred, at the same time being unaffected by IVF/ICSI treatment. In addition, the increased woman's age at IVF/ICSI treatment was identified as the only parameter elevating the biochemical pregnancy rate, whereas the clinical abortion rate was found to be unrelated to the clinical or embryological parameters studied.     

A prospective, randomized study comparing day 2 and day 3 embryo transfer in human IVF

It is believed that delayed transfer of embryos after IVF allows for a better selection of good quality embryos. Hence, the number of embryos and all other prognostic factors being equal, transfer of day 3 embryos should be associated with higher implantation and pregnancy rates than transfer of day 2 embryos. To investigate this hypothesis, a prospective randomized study was carried out to compare implantation and pregnancy rates between day 2 and day 3 transfers. The relationship between the embryo quality score of day 2 and day 3 embryos and their respective implantation rates was also analysed. In a 2 year period all patients undergoing infertility treatment and in whom at least seven normally fertilized oocytes were obtained were included in the study. A minimization procedure was performed taking into account the patient's age and the method of fertilization (IVF or intracytoplasmic sperm injection). By using a uniform policy of embryo transfer, the number of embryos transferred was similar in both groups. The outcome parameters were embryo quality, implantation and pregnancy rates. No difference was observed in implantation and pregnancy rates between transfers on day 2 versus day 3 (23.8 versus 23.8% and 47.9 versus 46.8% respectively). The incidence of embryos of moderate to poor quality was higher in embryos cultured for 3 days compared with those cultured for 2 days. It is concluded that the outcomes of embryo transfer in terms of implantation and pregnancy rates are comparable for day 2 and day 3 embryos, although the overall embryo quality score decreases when embryos are kept in culture till day 3.     

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.     

Selective transfer of cryopreserved human embryos with further cleavage after thawing increases delivery and implantation rates

We investigated whether further in-vitro culture of human multicellular embryos that survive cryopreservation can select the viable embryos for transfer. Embryos for cryopreservation were supernumerary multicellular embryos obtained after in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) treatments, with <20% of their volume filled with anucleate fragments. These had been cryopreserved using a slow-freezing and slow-thawing protocol with 1.5 M dimethylsulphoxide as the cryoprotectant. From the start of our cryopreservation programme until September 12, 1994, the thawing strategy was to thaw frozen embryos up to the exact number needed for transfer. Embryos for transfer were selected on the basis of their morphological appearance and embryo transfer to the patient was done on the day of thawing. From September 12, 1994 onwards we used a more selective thawing strategy where a cohort of up to a maximum of 12 frozen embryos per patient is thawed from which embryos of the best morphological quality, and which are furthest advanced in terms of cleavage after a 24 h in-vitro culture period in Menezo B2 medium, are selected. We took delivery rates, embryo implantation rates and birth rates into account to see if there is any difference between the following three types of transfers used: 187 transfers exclusively of embryos having continued to cleave after thawing, 107 mixed transfers of embryos with and without further cleavage and 53 transfers exclusively of embryos with no further cleavage. The overall outcome in terms of delivery rate and embryo implantation and birth rates were not different between the new and the earlier thawing policies (6.6, 5.2 and 3.6% versus 6.0, 4.1 and 2.7% respectively). Only when a distinction was made between transfers on the basis of the presence of embryos with further cleavage, did the advantage of selection on the basis of cleavage capacity become evident. Significantly higher delivery and embryo implantation and birth rates (11.2, 7.7 and 6.5% respectively) were recorded with transfers exclusively of embryos with further cleavage versus mixed transfers of embryos with and without further cleavage (1.9, 2.9 and 0.6% respectively). Fifty-three transfers exclusively of embryos with no further cleavage did not lead to any delivery. Our results demonstrate that selection of human multicellular embryos which survive cryopreservation and continue to cleave in vitro can significantly improve the delivery rate per transfer and the implantation rate per transferred embryo.      

高龄女性移植2枚或3枚卵裂期胚胎的临床效果比较

目的 探讨移植2枚或3枚胚胎与临床结局的关系,为高龄女性胚胎移植数的选择提供依据.方法 对80个卵裂期胚胎新鲜移植周期进行回顾性分析,根据移植胚胎数将这些周期分组,并对各组的临床妊娠率、种植率、多胎妊娠率及活产率进行比较.结果 对于年龄≥38岁的女性,当可利用胚胎数≥3枚时,移植2枚胚胎与移植3枚胚胎能够获得相似的临床...     

Day 2 elective single embryo transfer in clinical practice: better outcome in ICSI cycles

BACKGROUND: Single embryo transfer (SET) after IVF/ICSI has been shown to result in an acceptable pregnancy rate in selected subjects. In our unit, SET is routinely carried out among women under the age of 36 in the first or second treatment cycle when a top-quality embryo is available. In order to define further the selection criteria for SET, we have analysed the outcome of elective SET (eSET), including the cumulative pregnancy rate after frozen embryo transfers, performed in the years 2000-2002 in the Oulu Fertility Center. METHODS: During the study period, a total of 1271 transfers were performed, and in 468 cycles SET (39% of all transfers) was carried out. Of the SET cycles, in 308 cases a top-quality embryo was transferred on day 2 and extra embryos were frozen. Of these eSET cycles, ICSI was carried out in 87 cycles (28%). RESULTS: The overall clinical pregnancy rate per transfer was 34.7% in the eSET cycles. In the eSET ICSI cycles, the clinical pregnancy rate was significantly higher than in the corresponding IVF cycles (50.6 versus 28.5%, P < 0.001). The cumulative pregnancy rate per patient after fresh and frozen embryo transfers was also significantly higher after ICSI (71.2 versus 53.4%, P < 0.01). CONCLUSIONS: A high cumulative pregnancy rate per oocyte retrieval can be achieved after eSET in daily clinical practice. The implantation rate of fresh top-quality embryos in the ICSI cycles was significantly higher than in the IVF cycles, possibly due to more successful selection of the embryo for embryo transfer on day 2 after ICSI. In addition, our data suggest that embryo quality is a more important determinant of outcome than the age of the woman.     

Cost-effectiveness analysis of in-vitro fertilization: estimated costs per successful pregnancy after transfer of one or two embryos

Standard protocols for in-vitro fertilization (IVF) include transfer of two or three embryos. Not surprisingly, the rate of twin pregnancy after IVF is high (about 24% of all pregnancies). Routine transfer of one, rather than two, embryos would be expected to result in a much lower rate of twin pregnancies at the cost of a lower take-home baby rate. The aim of this study was to compare hypothetical costs to society incurred by pregnancies achieved with IVF protocols based on the transfer of one or two embryos. We compared actual (for two-embryo transfers) and hypothetical (for one-embryo transfers) take-home baby rates; risks of twin pregnancies; and costs of sick leave and hospitalization during pregnancy, deliveries, neonatal intensive care, and handicap care after transfer of one or two embryos. The study showed that even when more treatments might be needed to achieve similar baby take-home rates after transfer of one compared with two embryos, the lower twin pregnancy rate of the former approach caused it to be more cost-efficient than the latter. In conclusion, IVF costs are the sum of fertilization treatment costs and the costs for health care of the pregnant women and their offspring. Considering the association of the latter costs with numbers of embryos transferred, studies of one- embryo transfer protocols are urgently needed.      

Cryo-thawed embryos obtained from conception cycles have double the implantation and pregnancy potential of those from unsuccessful cycles

BACKGROUND: The purpose of this study was to evaluate the influence of fresh IVF/ICSI cycle outcome on the prognosis of the related frozen embryo replacement (FER) cycle. METHODS: 459 FER cycles, involving 2049 cleavage stage embryos with no or up to 10% fragmentation, were performed for which the outcome of the fresh cycle was recorded. The cycles were divided into two groups; group A included cycles in which cryopreserved embryos were obtained from fresh cycles in which conception occurred. Group B were cycles in which cryopreserved embryos originated from unsuccessful fresh cycles. RESULTS: Groups A and B were comparable with respect to mean (+/- SD) age at cryopreservation (33 +/- 3.9 versus 33.2 +/- 4 years, P = not significant), mean number of oocytes retrieved and fertilized normally in the fresh cycle (11 +/- 5.2 versus 11.2 +/- 4.8, P = not significant) and mean age at the cryo-thawed transfer (34.5 +/- 4.2 versus 33.9 +/- 4 years, P = not significant). No significant difference was found between the two groups with regard to mean number of embryos cryopreserved (6.5 +/- 3.9 versus 6.2 +/- 3.6) and subsequently thawed (4.5 +/- 2.5 versus 4.5 +/- 1.8) per cycle and number of cryo-thawed embryos transferred per cycle (2.0 +/- 0.7 versus 2.1 +/- 0.8). However, the implantation rate per transferred embryo in group A was double that in group B (23 versus 11.2%, P < 0.0001). Moreover, the clinical pregnancy and ongoing pregnancy rates per cycle were significantly higher in group A compared with group B (34.8 and 27.3% versus 15.6 and 13.1%, P < 0.0001 and P = 0.0003 respectively). The difference in FER cycle outcome could not be explained by confounding variables. CONCLUSIONS: After thawing, cryopreserved embryos originating from conception IVF/ICSI cycles achieve double the implantation and pregnancy rates of those obtained from unsuccessful cycles.     

Recurrence of hydrosalpinges after transvaginal aspiration of tubal fluid in an IVF cycle with development of a serometra

The presence of hydrosalpinges has been shown to be deleterious in infertility treatment. Pregnancy rates after in-vitro fertilization (IVF) with embryo transfer decline considerably. This study concerns a patient who developed bilateral hydrosalpinges during controlled ovarian stimulation in preparation for IVF treatment. Transvaginal aspiration of the tubal fluid was unsuccessful as the tubes refilled within 2 days. Additionally, on the day of embryo transfer a serometra developed which could not be seen on the day of oocyte retrieval. The uterine cavity was evacuated via an embryo transfer catheter and three embryos were transferred. The serometra reappeared 3 days after embryo transfer. A pregnancy could not be achieved. The accumulation of fluid in the uterine cavity during an IVF/embryo transfer cycle is a rare complication of hydrosalpinges. However, the retrograde flow of tubal fluid may disturb intrauterine embryo development. This study suggests that the aspiration of hydrosalpinges and intrauterine fluid accumulation during an IVF cycle is not beneficial, as the underlying pathology is not cured. Cancellation of the treatment cycle or cryopreservation of oocytes in the pronucleate stage and transfer of the cryopreserved oocytes after surgical correction of the tubes may be better options.      

Effect of developmental stage of embryo at freezing on pregnancy outcome of frozen-thawed embryo transfer

BACKGROUND: The study aim was to investigate the impact of the developmental stage of embryos on pregnancy outcome of frozen embryo transfer (FET). METHODS: The survival rates of embryos after thawing and pregnancy outcome following FET were compared retrospectively between three cryopreservation strategies utilizing either zygote, day 2 or day 3 embryo freezing. RESULTS: A total of 4006 embryos was analysed in 1657 thaw cycles. The highest (P < 0.0001) survival rate (all cells survived) was observed for zygotes (86.5%), followed by day 2 (61.7%) and day 3 (43.1%) embryos. FET was performed in 1586 (95.7%) of all thaw cycles, resulting in overall clinical pregnancy and implantation rates of 20.7 and 14.2% respectively. The delivery rate per transfer was 16.5%, and live birth rate per transferred embryo 11%. There were no significant differences in clinical pregnancy, implantation, delivery and birth rates between frozen zygote, day 2 and 3 embryo transfers. However, an elevated miscarriage rate was observed in the day 3 group (45%) compared with zygotes (21.3%; P = 0.049) and day 2 embryos (18.3%; P = 0.004). The overall efficacy of FET (birth rate per thawed embryo) was 7.3%. The efficacy was lower in day 3 group (4.2%) than in the zygote (7.1%; P = 0.082) and day 2 (7.6%; P = 0.027) groups. CONCLUSIONS: The developmental stage of embryos at freezing has a profound effect on their post-thaw survival, but seems to have little effect on rates of clinical pregnancy, implantation, delivery and birth after FET. The elevated miscarriage rate for day 3 frozen embryo transfers may be caused by damage during freeze-thaw procedures. The low survival rate and elevated miscarriage rate were both responsible for a reduced overall efficacy for day 3 FET when compared with zygotes and day 2 embryos.     

Embryos cultured in vitro with multinucleated blastomeres have poor implantation potential in human in-vitro fertilization and intracytoplasmic sperm injection

The aim of the present study was to investigate pregnancy rates ensuing from transfer of embryos with multinucleated blastomeres. In our in- vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) programme, 1735 embryo transfers were performed from January 1, 1995 to August 31, 1996. In 136 of these transfers at least one embryo with one or more multinucleated blastomeres was present per transfer (study group). For each of these 136 transfers, two matched controls with transfer of exclusively mononucleated embryos were selected (control group). Matching was carried out according to age, method of fertilization (IVF or ICSI), number of transferred embryos and quality score of transferred embryos. In the study group, there were eight transfers of exclusively multinucleated embryos from which one pregnancy ensued and 128 transfers in which multinucleated and mononucleated embryos were transferred together leading to 23 pregnancies. The overall clinical pregnancy rate per transfer was 16.9% in the study group versus 28.7% in the control group (P = 0.01). The ongoing pregnancy rate per transfer was 13.2% in the study group versus 23.2% in the control group (P = 0.03). The implantation rate per transferred embryo was 6.0% in the study group versus 11.3% in the control group (P = 0.003). This study shows that embryos with one or more multinucleated blastomeres have a poorer implantation potential than embryos with mononucleated blastomeres. Transfer of embryos with multinucleated blastomeres should hence only be considered when insufficient numbers of embryos with only mononucleated blastomeres are present.