Single-embryo transfer versus multiple-embryo transfer

Microfluidic chip as a promising evaluation method in assisted reproduction: A systematic review

The aim of assisted reproductive technology (ART) is to select the high-quality sperm, oocytes, and embryos, and finally achieve a successful pregnancy. However, functional evaluation is hindered by intra- and inter-operator variability. Microfluidic chips emerge as the one of the most powerful tools to analyze biological samples for reduced size, precise control, and flexible extension. Herein, a systematic search was conducted in PubMed, Scopus, Web of Science, ScienceDirect, and IEEE Xplore databases until March 2023. We displayed and prospected all detection strategies based on microfluidics in the ART field. After full-text screening, 71 studies were identified as eligible for inclusion. The percentages of human and mouse studies equaled with 31.5%. The prominent country in terms of publication number was the USA (n = 13). Polydimethylsiloxane (n = 49) and soft lithography (n = 28) were the most commonly used material and fabrication method, respectively. All articles were classified into three types: sperm (n = 38), oocytes (n = 20), and embryos (n = 13). The assessment contents included motility, counting, mechanics, permeability, impedance, secretion, oxygen consumption, and metabolism. Collectively, the microfluidic chip technology facilitates more efficient, accurate, and objective evaluation in ART. It can even be combined with artificial intelligence to assist the daily activities of embryologists. More well-designed clinical studies and affordable integrated microfluidic chips are needed to validate the safety, efficacy, and reproducibility. Trial registration: The protocol was registered in the Open Science Frame REGISTRIES (identification: osf.io/6rv4a).

Cumulus cell antioxidant system is modulated by patients' clinical characteristics and correlates with embryo development

PURPOSE

To study whether the cumulus cell antioxidant system varies accordingly to patients clinical characteristics' as age, infertility diagnosis, BMI, and stimulation protocol applied and if the antioxidant profile of cumulus cells could be used as a predictor of embryo development.

METHODS

A prospective study including 383 human cumulus samples provided by 191 female patients undergoing intracytoplasmic sperm injection during in vitro fertilization treatments from a local in vitro fertilization center and processed in university laboratories. Catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione S-transferase (GST) enzyme activity levels and reduced glutathione (GSH) levels were measured in cumulus oophorus cells individually collected from each aspirated cumulus-oocyte complex, and the results of each sample were compared considering the oocytes outcome after ICSI and patients clinical characteristics. A total of 223 other human cumulus samples from previous studies were submitted to a gene expression meta-analysis.

RESULTS

The antioxidant system changes dramatically depending on patients' age, infertility diagnosis, stimulation protocol applied, and oocyte quality. SOD activity in cumulus cells revealed to be predictive of top-quality blastocysts for young patients with male factor infertility (P < 0.05), while GST levels were shown to be extremely influenced by infertility cause (P < 0.0001) and stimulation protocol applied (P < 0.05), but nonetheless, it can be used as a complementary tool for top-quality blastocyst prediction in patients submitted to intracytoplasmic sperm injection technique (ICSI) by male factor infertility (P < 0.05).

CONCLUSION

Through a simple and non-invasive analysis, the evaluation of redox enzymes in cumulus cells could be used to predict embryo development, in a personalized matter in specific patient groups, indicating top-quality oocytes and improving success rates in in vitro fertilization treatments.

TRIAL REGISTRATION

The trial was registered at UFRGS Research Ethics Committee and Plataforma Brasil under approval number 68081017.2.0000.5347 in June 6, 2019.

Pregnancy and obstetric outcomes of dichorionic and trichorionic triamniotic triplet pregnancy with multifetal pregnancy reduction: a retrospective analysis study

Background

It is generally beneficial for triplet gestation or high-order multiple pregnancies to operate multifetal pregnancy reduction (MFPR) after assisted reproductive techniques. However, data on pregnancy outcomes is lacking regarding dichorionic triamniotic (DCTA) and trichorionic triplets (TCTA) pregnancy.

Method

This research analyzes the difference between 128 DCTA and 179 TCTA pregnancies with or without MFPR after in vitro fertilization/intracytoplasmic sperm injection cycles between January 2015 and June 2020. The subdivided subgroups of the two groups are reduction to singleton, reduction to dichorionic twins, and expectant management groups. We also compare the pregnancy and obstetric outcomes between 2104 dichorionic twins and 122 monochorionic twins.

Result

The research subgroups were DCTA to monochorionic singleton pregnancies (n = 76), DCTA to dichorionic twin pregnancies (n = 18), DCTA-expectant management (n = 34), TCTA to monochorionic singleton pregnancies (n = 31), TCTA to dichorionic twin pregnancies (n = 130), and TCTA-expectant management (n = 18). In DCTA-expectant management group, the complete miscarriage rate is dramatically higher, and the survival rate and the rate of take-home babies are lower. However, there was no difference between the rates of complete miscarriages, survival rates, and take-home babies in TCTA-expectant management group. But the complete miscarriage rate of DCTA-expectant management was obviously higher than that of TCTA-expectant management group (29.41 vs. 5.56%, p = 0.044). For obstetric outcomes, MFPR to singleton group had higher gestational week and average birth weight, but lower premature delivery, gestational hypertension rates and low birth weight in both DCTA and TCTA pregnancy groups (all p < 0.05). DCTA to monochorionic singleton had the lowest incidence of gestational diabetes, whereas The subdivided subgroups of TCTA had no significant difference in the incidence of gestational diabetes. Monochorionic twins have higher rates of complete, early, and late miscarriage, premature delivery, and late premature delivery, and lower survival rate (p < 0.05).

Conclusion

MFPR could improve gestational week and average birth weight, reducing premature delivery, LBW, and gestational hypertension rates in DCTA and TCTA pregnancies. Monochorionic twins have worse pregnancy and obstetric outcomes. MFPR to singleton is preferable recommended in the pregnancy and obstetric management of complex triplets with monochorionic pair.

Protective placental inflammatory and oxidative stress responses are attenuated in the context of twin pregnancy and chorioamnionitis in assisted reproduction

PURPOSE

Assisted reproduction technologies (ART) are associated with increased risks of pregnancy complications and obstetric interventions. Here, we aimed to determine if ART affects placental inflammation and oxidative stress as a mechanism for unfavorable pregnancy outcomes.

METHODS

The levels of six cytokines (IFN-γ, IL-1β, IL-6, IL-8, IL-10, TNFα) were measured using multiplex ELISA. The activity of four antioxidant enzymes (glutathione S-transferase (GST), glutathione peroxidase (GPx), glutathione reductase, superoxide dismutase) and levels of two antioxidants (GSH, vitamin E) were measured using commercial/in-house assays. Markers were compared between ART and unassisted pregnancies, and then groups were stratified using ICD9/10 codes to determine differences in specific clinical contexts.

RESULTS

In unassisted twin pregnancies, there was a trend of decreased cytokine levels (IL-1β, IL-6, IL-8, TNFα, p < 0.05), but cytokines in ART twins were the same or higher. Additionally, GST and GPx activities were lower in unassisted twins, and vitamin E levels were higher in ART twins (p < 0.05). In pregnancies complicated by chorioamnionitis, there was a trend of increased cytokine levels in unassisted pregnancies (IL-1β, IL-6, and IL-8, p < 0.05). No increase was observed in ART, and IFN-γ and TNFα were decreased (p < 0.05). Placental GST and GPx activities were higher in unassisted pregnancies with chorioamnionitis compared to ART (p < 0.05).

CONCLUSION

Attenuation of protective placental inflammatory and oxidative stress responses may play a role in the underlying pathogenesis of negative birth outcomes in ART, expanding our understanding of adverse pregnancy outcomes when ART is used to conceive.

Maternal and perinatal outcomes after fresh versus frozen embryo transfer-what is the risk-benefit ratio?

Fresh ET has been the conventional strategy in IVF, but there is a growing opinion suggesting that its maternal and perinatal outcomes can be enhanced by a policy of elective freezing of embryos, followed by transfer at a later date. Available studies suggest a number of improved maternal and perinatal outcomes after frozen ET, although there is also a suggestion of large for gestational age babies associated with this strategy. The observational nature of the available data limit our confidence in the results of available studies. A genuinely unbiased estimate of the advantages of a policy of elective ET can only be confirmed by a definitive randomized controlled trial with an adequate length of follow-up of the offspring.

The fertilization-induced zinc spark is a novel biomarker of mouse embryo quality and early development

Upon activation, mammalian eggs release billions of zinc ions in an exocytotic event termed the “zinc spark.” The zinc spark is dependent on and occurs coordinately with intracellular calcium transients, which are tightly associated with embryonic development. Thus, we hypothesized that the zinc spark represents an early extracellular physicochemical marker of the developmental potential of the zygote. To test this hypothesis, we monitored zinc exocytosis in individual mouse eggs following parthenogenetic activation or in vitro fertilization (IVF) and tracked their development. Retrospective analysis of zinc spark profiles revealed that parthenotes and zygotes that developed into blastocysts released more zinc than those that failed to develop. Prospective selection of embryos based on their zinc spark profile significantly improved developmental outcomes and more than doubled the percentage of embryos that reached the blastocyst stage. Moreover, the zinc spark profile was also associated with embryo quality as the total cell number in the resulting morulae and blastocysts positively correlated with the zinc spark amplitude (R = 0.9209). Zinc sparks can thus serve as an early biomarker of zygote quality in mouse model.

Obstetric and perinatal outcome from single cleavage transfer and single blastocyst transfer: a matched case-control study

AIM

To evaluate a possible relationship between extended embryo culture and outcome of pregnancies resulting from single embryo transfers (SETs).

DESIGN

A retrospective matched case-control study Setting: University fertility center Patients: About 106 live births from single cleavage embryo transfers were matched 1:2 with 212 live births from single blastocyst transfers.

INTERVENTIONS

A cohort of 3522 fresh SETs using non-donor oocytes in women ≤40 years old from August 2010 to December 2013. Live births were matched by maternal age, body mass index, smoking and parity. Adjustments were made for gender of the baby and embryo quality. Obstetric and perinatal outcomes including birth weight, low birth weight, small for gestational age, preterm delivery, preeclampsia, placental abruption and neonatal complications were compared.

RESULTS

Matched live birth outcomes showed no increased risk of obstetric or perinatal complications in pregnancies resulting from single blastocyst transfers compared to single cleavage transfers.

CONCLUSIONS

Extended culture was not associated with increased adverse obstetric and perinatal outcome in pregnancies resulting from fresh SETs in this study.

Use of both cumulus cells' transcriptomic markers and zona pellucida birefringence to select developmentally competent oocytes in human assisted reproductive technologies

BACKGROUND

Selection of the best oocyte for subsequent steps of fertilization and embryo transfer was shown to be the crucial step in human infertility treatment procedure. Oocyte selection using morphological criteria mainly Zona pellucida (ZP) has been the gold standard method in assisted reproductive technologies (ART) clinics, but this selection approach has limitations in terms of accuracy, objectivity and constancy. Recent studies using OMICs-based approaches have allowed the identification of key molecular markers that quantitatively and non-invasively predict the oocyte quality for higher pregnancy rates and efficient infertility treatment. These biomarkers are a valuable reinforcement of the morphological selection criteria widely used in in vitro fertilization (IVF) clinics. In this context, this study was designed to investigate the relationship between transcriptomic predictors of oocyte quality found by our group and the conventional morphological parameters of oocyte quality mainly the ZP birefringence.

RESULTS

Microarray data revealed that 48 and 27 differentially expressed candidate genes in cumulus cells (CCs) were respectively overexpressed and underexpressed in the ZGP (Zona Good Pregnant) versus ZBNP (Zona Bad Non Pregnant) groups. More than 70% of previously reported transcriptomic biomarkers of oocyte developmental competence were confirmed in this study. The analysis of possible association between ZP birefringence versus molecular markers approach showed an absence of correlation between them using the current set of markers.

CONCLUSIONS

This study suggested a new integrative approach that matches morphological and molecular approaches used to select developmentally competent oocytes able to lead to successful pregnancy and the delivery of healthy baby. For each ZP birefringence score, oocytes displayed a particular CCs' gene expression pattern. However, no correlations were found between the 7 gene biomarkers of oocyte developmental potential and the ZP birefringence score. Further studies using larger lists of candidate markers are required to identify suitable genes that are highly correlated with the morphological criteria, and therefore able to reinforce the accuracy of oocyte selection and the effectiveness of infertility treatment.

Individualized medicine enabled by genomics in Saudi Arabia

The biomedical research sector in Saudi Arabia has recently received special attention from the government, which is currently supporting research aimed at improving the understanding and treatment of common diseases afflicting Saudi Arabian society. To build capacity for research and training, a number of centres of excellence were established in different areas of the country. Among these, is the Centre of Excellence in Genomic Medicine Research (CEGMR) at King Abdulaziz University, Jeddah, with its internationally ranked and highly productive team performing translational research in the area of individualized medicine. Here, we present a panorama of the recent trends in different areas of biomedical research in Saudi Arabia drawing from our vision of where genomics will have maximal impact in the Kingdom of Saudi Arabia. We describe advances in a number of research areas including; congenital malformations, infertility, consanguinity and pre-implantation genetic diagnosis, cancer and genomic classifications in Saudi Arabia, epigenetic explanations of idiopathic disease, and pharmacogenomics and personalized medicine. We conclude that CEGMR will continue to play a pivotal role in advances in the field of genomics and research in this area is facing a number of challenges including generating high quality control data from Saudi population and policies for using these data need to comply with the international set up.

Embryo vitrification using a novel semi-automated closed system yields in vitro outcomes equivalent to the manual Cryotop method

STUDY QUESTION

Can the equilibration steps prior to embryo vitrification be automated?

SUMMARY ANSWER

We have developed the 'Gavi' system which automatically performs equilibration steps before closed system vitrification on up to four embryos at a time and gives in vitro outcomes equivalent to the manual Cryotop method.

WHAT IS KNOWN ALREADY

Embryo cryopreservation is an essential component of a successful assisted reproduction clinic, with vitrification providing excellent embryo survival and pregnancy outcomes. However, vitrification is a manual, labour-intensive and highly skilled procedure, and results can vary between embryologists and clinics. A closed system whereby the embryo does not come in direct contact with liquid nitrogen is preferred by many clinics and is a regulatory requirement in some countries.

STUDY DESIGN, SIZE, DURATION

The Gavi system, an automation instrument with a novel closed system device, was used to equilibrate embryos prior to vitrification. Outcomes for embryos automatically processed with the Gavi system were compared with those processed with the manual Cryotop method and with fresh (non-vitrified) controls.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The efficacy of the Gavi system (Alpha model) was assessed for mouse (Quackenbush Swiss and F1 C57BL/6J x CBA) zygotes, cleavage stage embryos and blastocysts, and for donated human vitrified-warmed blastocysts. The main outcomes assessed included recovery, survival and in vitro embryo development after vitrification-warming. Cooling and warming rates were measured using a thermocouple probe.

MAIN RESULTS AND THE ROLE OF CHANCE

Mouse embryos vitrified after processing with the automated Gavi system achieved equivalent in vitro outcomes to that of Cryotop controls. For example, for mouse blastocysts both the Gavi system (n = 176) and manual Cryotop method (n = 172) gave a 99% recovery rate, of which 54 and 50%, respectively, progressed to fully hatched blastocysts 48 h after warming. The outcomes for human blastocysts processed with the Gavi system (n = 23) were also equivalent to Cryotop controls (n = 13) including 100% recovery for both groups, of which 17 and 15%, respectively, progressed to fully hatched blastocysts 48 h after warming. The cooling and warming rates achieved with the Gavi system were 14 136°C/min and 11 239°C/min, respectively.

LIMITATIONS, REASONS FOR CAUTION

Testing of the Gavi system described here was limited to in vitro development of embryos from two mouse strains and a limited number of human embryos. Validation of Gavi system advanced production models is now required to confirm the success of semi-automated vitrification, including clinical evaluation of pregnancy outcomes from the transfer of Gavi vitrified-warmed human embryos.

WIDER IMPLICATIONS OF THE FINDINGS

The Gavi system has the potential to revolutionize and standardize vitrification of embryos and oocytes. The success of the Gavi system shows that it is possible to semi-automate complicated labour-intensive ART methods and processes, and opens up the possibility for further improvements in clinical outcomes and efficiencies in the ART clinic.

STUDY FUNDING/COMPETING INTERESTS

This study was funded by Genea Ltd. S.B., N.M.T., T.T.P., S.J.M., M.C.B. and T.S. are shareholders of Genea Ltd. E.V., C.H., C.L., S.R.L. and S.M.D. are shareholders of Planet Innovation Pty Ltd. The remaining authors are employees of either Genea Ltd. or Planet Innovation Pty Ltd.

Embryo selection strategy in sibling oocytes: a novel approach to measuring the likelihood of single‑embryo transfer using a mouse embryo transfer model

The present study investigated the effect of embryo transfer on post-implantation development using different fertilization approaches in sibling oocyte procedures. C57BL/6, DBA/2, C3H/HeJ and ICR mice were used at 8-10 weeks of age. Mature oocytes were collected, divided into two groups and fertilized using in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). Different numbers of the resulting blastocysts were then transferred into recipients and designated as either: The single embryo transfer (SET) I model (one transferred embryo), the SET II model (six transferred embryos) or the multiple embryo transfer (MET) model (24 transferred embryos). The development efficiency, cell number, number of apoptotic cells in blastocysts, pregnancy efficiency, delivery rate and cumulative pregnancy efficiency were analyzed. IVF-fertilized embryos exhibited higher blastocyst development competence and embryo quality compared with ICSI embryos. The pregnancy and delivery efficiency was not identified to be significantly different between the two SET models, but it was lower in these two models than in the MET model. The cumulative pregnancy efficiency in SET models, calculated using a mathematical equation, was not decreased. In conclusion, embryo quality was shown to be the primary factor in selecting embryos prior to embryo transfer using sibling oocytes. In addition, single blastocyst transfer can be performed in sibling oocytes without compromising cumulative pregnancy rates, independent of the fertilization approach.

Long-term follow-up of children conceived through assisted reproductive technology

Children conceived via assisted reproductive technologies (ART) are nowadays a substantial proportion of the population. It is important to follow up these children and evaluate whether they have elevated health risks compared to naturally conceived (NC) children. In recent years there has been a lot of work in this field. This review will summarize what is known about the health of ART-conceived children, encompassing neonatal outcomes, birth defects, growth and gonadal developments, physical health, neurological and neurodevelopmental outcomes, psychosocial developments, risk for cancer, and epigenetic abnormalities. Most of the children conceived after ART are normal. However, there is increasing evidence that ART-conceived children are at higher risk of poor perinatal outcome, birth defects, and epigenetic disorders, and the mechanism(s) leading to these changes have not been elucidated. Continuous follow-up of children after ART is of great importance as they progress through adolescence into adulthood, and new ART techniques are constantly being introduced.

Comparison of Blastocyst Development and Cycle Outcome in Patients with eSET Using Either Conventional or Time Lapse Incubators. A Prospective Study of Good Prognosis Patients

The aim of this study is to compare blastocyst development and cycle outcomes of good prognosis elective single embryo transfer patients using conventional or time lapse incubators. A randomized study was designed to evaluate embryo development until the blastocyst stage in either conventional or time-lapse incubators in good prognosis patients. Furthermore cycle outcomes of the patients were evaluated. The study involved 64 patients (33 for time-lapse and 31 for conventional incubation) in their first or second treatment cycle, with no recurrent spontaneous miscarriages, age<35 years, body mass index <28 kg/m2 and ≥8 oocytes retrieved. The primary outcome was the proportion of good and top quality blastocysts on day 5 and the secondary outcome was the implantation and pregnancy rates after elective single embryo transfer in good prognosis patients. The analysis performed revealed no statistical difference between both groups for blastocyst development, implantation and clinical pregnancy rates. In a selected good prognosis elective single embryo transfer population, similar rates of good and top quality blastocysts and comparable implantation and pregnancy rates were achieved. However, the stable culture conditions provided by time-lapse incubators and the use of morphokinetic parameters may allow the selection of the best available embryos with high developmental capacity, especially in poor prognosis patients.

Advances in embryo selection methods

Despite many recent advances in the field of reproductive biology and medicine, the efficiency of in vitro fertilization procedures remains relatively low. There is a need for a reliable and non-invasive method of embryo selection to ensure that only embryos with the highest developmental potential are chosen for transfer to mothers-to-be. Here, we compare various methods currently used for assessing embryonic viability, such as examination of embryonic morphology, quality of the genetic material, or metabolism. Additionally, we discuss novel procedures for embryonic assessment based on advanced time-lapse imaging techniques, which show great promise and may lead to increased in vitro fertilization efficiencies.

Trends and factors associated with the Day 5 embryo transfer, assisted reproductive technology surveillance, USA, 2001-2009

STUDY QUESTION

What characteristics are associated with a Day 5 embryo transfer?

SUMMARY ANSWER

The use of the Day 5 embryo transfer has increased over time, with clinicians allowing women with typically 'poorer' prognostic characteristics to undergo a Day 5 embryo transfer. The mean number of embryos per Day 5 transfer decreased from 2001 to 2009, although the prevalence of the Day 5 single embryo transfer remains low and the rate of multiple births remains substantial.

WHAT IS KNOWN AND WHAT THIS PAPER ADDS

Day 5 embryo transfer may reduce the rate of multiple gestation pregnancy. US trends over time in the prevalence of the Day 5 transfer, changes in characteristics of patients receiving Day 5 transfer, and number of embryos transferred are unknown.

DESIGN

We used 2001-2009 US National assisted reproductive technology (ART) Surveillance System (NASS) data on 620,295 fresh IVF cycles derived from autologous oocytes with a Day 3 or 5 embryo transfer. Trends in the mean number of embryos transferred from 2001 to 2009 were assessed by the day of transfer. For 349,947 cycles from clinics performing both Days 3 and 5 embryo transfers, multivariable logistic regression was used to determine the characteristics associated with the Day 5 embryo transfer. We also compared the characteristics of the Day 5 embryo cycles in 2001 and 2009.

MAIN RESULTS AND THE ROLE OF CHANCE

Overall, the proportion of ART cycles using the Day 5 embryo transfer increased from 12% in 2001 to 36% in 2009 (P<0.0001), while the mean number of embryos transferred decreased from 2.4 to 2.1 (P<0.0001). Among Day 5 transfers, the rate of the single embryo transfer tripled from 4.5% in 2001 to 14.8% in 2009 (P<0.0001); and the rate of multiple births decreased from 44.8 to 41.1% (P<0.0001). In cycles initiated after 2001, maternal age<35 years, no prior ART cycles, ≥1 prior pregnancies, baseline follicle stimulating hormone<10 international units and ≥10 oocytes retrieved were associated with the Day 5 embryo transfer. Compared with 2001, in 2009, a broader range of candidates received the Day 5 transfer. BIAS Women undergoing multiple ART cycles over time are not linked.

CONFOUNDING FACTORS AND OTHER REASONS FOR CAUTION

We ran multivariable logistic regression to lessen the effects of the confounding factors. Cycle cancelation rates by the day of embryo transfer are unknown.

GENERALIZABILITY TO OTHER POPULATIONS

Generalizable to ART clinics included in NASS.

STUDY FUNDING/COMPETING INTERESTS

This study was funded by the Centres for Disease Control. The authors have no competing interests to declare.

[Parents of multiple births after assisted conception]

BACKGROUND

A major criticism is the increase in multiple pregnancies after ART in the past 30 years and the associated fetal and maternal risks.

MATERIAL

Few studies examined the psychosocial risks of the parents of multiple births after ART, for example psychology adjustment, parenting stress, education problems, anxiety, depression, relationship problems or social isolation.

RESULTS

The research confirms the psychosocial characteristics after multiple births. In the early postpartum period there is increased risk of depressive disorders. Mothers of twins after ART show a limitation of their psychosocial well-being compared to mothers of singles after ART.

DISCUSSION

Higher expectations of parenthood during pregnancy, less sufficiency coping strategies, and consequently, greater parental stress show twin mothers after ART in comparison to twin mothers after nature conception. An interdisciplinary postpartum care services makes sense. However, clinicians should keep attention to potential psychosocial burden of a multiple birth.

Working to eliminate multiple pregnancies: a success story in Québec

In August 2010, the provincial government of Québec, Canada introduced funding of assisted reproduction treatment through the provincial health programme. Alongside this benefit, legislation was introduced to control assisted reproduction treatment activities in the province, including restrictions on the number of embryos that could be transferred in any one cycle. The aim of the programme was to transfer a single embryo in every cycle; multiple embryos could be transferred under suboptimal conditions but required physician justification. In the first 3 months of this programme, 1353 cycles of IVF were performed in five Québec assisted reproduction centres, with an overall clinical pregnancy rate of 32% per embryo transfer and 50% of transfers used elective single-embryo transfer (eSET). The multiple-pregnancy rate was only 3.7% per clinical pregnancy. In 2009, prior to the introduction of the programme, eSET was used in only 1.6% of embryo transfers, resulting in a multiple-pregnancy rate of 25.6%. These data demonstrate that providing provincially funded assisted reproduction treatment created an environment in which the aggressive use of eSET was not only possible, but also rapidly implemented. The result was a dramatic drop in multiple-pregnancy rates, approaching those for natural pregnancies.

Childhood outcomes of assisted reproductive technology

There is a large population of children conceived via assisted reproductive technology (ART), which continues to increase worldwide, without a clear understanding of associated long-term outcomes. ART children are more likely to be the result of multiple pregnancies, and thus to be born prematurely or low birthweight. There is growing evidence that ART children are phenotypically and biochemically different from naturally conceived children, but the mechanism(s) leading to these changes have not been elucidated. There is a possible increased risk of rare imprinted gene disorders in these children. However, it remains unclear whether more subtle changes in DNA methylation occur commonly, leading to differences in gene expression and phenotype in ART children. Although an increased risk of cancer among ART children has been reported, the role of ART in the development of cancer has not been demonstrated. Further research and ongoing surveillance of ART children is essential to better understand the possible effects of ART on the long-term health of this population.

Oocyte developmental competence and embryo development: impact of lifestyle and environmental risk factors

Oocyte development is the end result of a sophisticated biological process that is hormonally regulated and produced by highly specialized cellular lines that differentiate in early embryo/fetal development. Embryo development is initially regulated by maternal transcripts until replaced by embryonic genomic expression. Then, an assortment of hormones and local environmental factors in various concentrations along the reproductive tract (e.g. fallopian tube, endometrial lining) provide the protection, nutrients and means of communication for the embryo to implant and develop. Both oocytes and embryos are susceptible to environmental, occupational and lifestyle exposures that can exert direct toxic effects and disrupt hormones. While some exposures may produce reversible changes, others, especially those damaging germinal cells in utero or during prepuberty, may result in permanent sequelae that continue in future generations. This article reviews the main factors that affect female fertility and their possible influence on human reproduction. Some lifestyles, xeno-oestrogens and heavy metals are already known to compromise female reproductive function. Nonetheless, many questions remain and little is known about the effect of many other factors on female fertility.

Biomarkers of human oocyte developmental competence expressed in cumulus cells before ICSI: a preliminary study

PURPOSE

To identify reliable genomic biomarkers expressed in cumulus cells that accurately and non-invasively predict the oocyte developmental competence and reinforce the already used morphological criteria.

METHODS

Eight consenting patients were selected for ovarian stimulation and ICSI procedures. Cumulus-oocyte complexes were transvaginally punctured and individually selected based on both good morphological criteria and high zona pellucida birefringence. Following ICSI, two 3-day embryos per patient were transferred. Pregnancy outcome was recorded and proven implantation was thereafter confirmed. Differential gene expression was assessed using two microarray platforms. Further real-time PCR validation, Ingenuity pathways analysis and intra-patient analysis were performed on 17 selected candidates.

RESULTS

Seven genes were differentially (p ≤ 0.05) associated to successful pregnancy and implantation. These biomarkers could be used to predict the oocyte developmental competence.

CONCLUSIONS

These genomic markers are a powerful reinforcement of morphological approaches of oocyte selection. Their large-scale validation could increase pregnancy outcome and single embryo transfer efficiency.

Clinical pregnancy and live births after transfer of embryos vitrified on day 3

Human embryo vitrification is a promising new technology but clinical outcome data is needed to gauge its effectiveness and safety. While pregnancy and live-birth data is available for blastocyst vitrification, such information is lacking for human embryo vitrification at the 6- to 8-cell stage. The current work presents clinical and obstetric outcomes from the transfer of embryos vitrified on day 3 at the cleavage stage. A total of 270 transfers were performed. The clinical pregnancy and implantation rates for patients under 38 years of age (n=200) were 45% and 24%, respectively. Corresponding rates in patients 38-42 years old declined to 29% and 13% (n=70). Embryonic compaction and/or blastulation by the time of transfer were excellent prognostic indicators of a successful pregnancy outcome. Of the 66 deliveries, 12 (18.2%) were twin pregnancies and nine were preterm (13.6%). The mean birthweight for singletons was 3281+/-644 g, compared with 2506+/-549 g in the twin pregnancies. A total of 78 infants have been born with no major congenital malformations. These data attest to the efficacy and safety of the vitrification technique for cryopreservation of human embryos at the 6- to 8-cell stage.