Comparable clinical outcomes and live births after single vitrified-warmed and fresh blastocyst transfer

Untangling the independent effect of endometriosis, adenomyosis, and ART-related factors on maternal, placental, fetal, and neonatal adverse outcomes: results from a systematic review and meta-analysis

BACKGROUND

Women with endometriosis may constitute a group at a particularly increased risk of pregnancy-related complications. Furthermore, women selected for assisted reproductive technology (ART) are exposed to additional endocrinological and embryological factors that have been associated with adverse pregnancy outcomes.

OBJECTIVE AND RATIONALE

This study aimed to investigate the independent effect of endometriosis, adenomyosis, and various ART-related factors on adverse maternal, placental, fetal, and neonatal outcomes.

SEARCH METHODS

Published randomized controlled trials, cohort studies, and case-control studies were considered eligible. PubMed, MEDLINE, ClinicalTrials.gov, Embase, and Scopus were systematically searched up to 1 March 2024. This systematic review and meta-analysis was performed in line with the PRISMA and the MOOSE reporting guidelines. To thoroughly investigate the association between endometriosis/adenomyosis and adverse pregnancy outcomes, sub-analyses were conducted, whenever possible, according to: the method of conception (i.e. ART and non-ART conception), the endometriosis stage/phenotype, the coexistence of endometriosis and adenomyosis, any pre-pregnancy surgical treatment of endometriosis, and the form of adenomyosis. The odds ratio (OR) with 95% CI was used as effect measure. The quality of evidence was assessed using the GRADE approach.

OUTCOMES

We showed a higher risk of placenta previa in women with endometriosis compared to controls (34 studies, OR 2.84; 95% CI: 2.47, 3.26; I2 = 83%, moderate quality). The association was observed regardless of the method of conception and was particularly strong in the most severe forms of endometriosis (i.e. rASRM stage III-IV endometriosis and deep endometriosis (DE)) (OR 6.61; 95% CI: 2.08, 20.98; I2 = 66% and OR 14.54; 95% CI: 3.67, 57.67; I2 = 54%, respectively). We also showed an association, regardless of the method of conception, between endometriosis and: (i) preterm birth (PTB) (43 studies, OR 1.43; 95% CI: 1.32, 1.56; I2 = 89%, low quality) and (ii) cesarean section (29 studies, OR 1.52; 95% CI: 1.41, 1.63; I2 = 93%, low quality). The most severe forms of endometriosis were strongly associated with PTB. Two outcomes were associated with adenomyosis both in the main analysis and in the sub-analysis that included only ART pregnancies: (i) miscarriage (14 studies, OR 1.83; 95% CI: 1.53, 2.18; I2 = 72%, low quality) and (ii) pre-eclampsia (7 studies, OR 1.70; 95% CI: 1.16, 2.48; I2 = 77%, low quality). Regarding ART-related factors, the following associations were observed in the main analysis and confirmed in all sub-analyses conducted by pooling only risk estimates adjusted for covariates: (i) blastocyst stage embryo transfer (ET) and monozygotic twinning (28 studies, OR 2.05; 95% CI, 1.72, 2.45; I2 = 72%, low quality), (ii) frozen embryo transfer (FET) and (reduced risk of) small for gestational age (21 studies, OR 0.59; 95% CI, 0.57, 0.61; P < 0.00001; I2 = 17%, very low quality) and (increased risk of) large for gestational age (16 studies, OR 1.70; 95% CI, 1.60, 1.80; P < 0.00001; I2 = 55%, very low quality), (iii) artificial cycle (AC)-FET and pre-eclampsia (12 studies, OR 2.14; 95% CI: 1.91-2.39; I2 = 9%, low quality), PTB (21 studies, OR 1.24; 95% CI 1.15, 1.34; P < 0.0001; I2 = 50%, low quality), cesarean section (15 studies, OR 1.59; 95% CI 1.49, 1.70; P < 0.00001; I2 = 67%, very low quality) and post-partum hemorrhage (6 studies, OR 2.43; 95% CI 2.11, 2.81; P < 0.00001; I2 = 15%, very low quality).

WIDER IMPLICATIONS

Severe endometriosis (i.e. rASRM stage III-IV endometriosis, DE) constitutes a considerable risk factor for placenta previa and PTB. Herein, we recommend against superimposing on this condition other exposure factors that have a strong association with the same obstetric adverse outcome or with different outcomes which, if coexisting, could determine the onset of an ominous obstetric syndrome. Specifically, we strongly discourage the use of AC regimens for FET in ovulatory women with rASRM stage III-IV endometriosis or DE. We also recommend single ET at the blastocyst stage in this high-risk population.

REGISTRATION NUMBER

CRD42023401428.

Should we should consider day 3 blastomere number during single vitrified-warmed blastocyst transfer cycle? A retrospective study

The present study investigated whether day 3 blastomere number has an effect on the clinical outcomes during single vitrified-warmed blastocyst transfer cycles. A total of 3294 vitrified-warmed single day 5 blastocyst transferred cycles were analyzed in this retrospective study from January 2018 to December 2021. The cycles were divided into ≥ 7 and < 7 blastomere groups depending on the day 3 embryo blastomere number. The clinical outcomes were compared between the two groups, moreover multivariate logistic regression analysis was conducted to investigate the correlation between the number of day 3 blastomeres and clinical outcomes. The chi-square test demonstrated that the rates of clinical pregnancy and live birth were significantly higher in the ≥ 7 blastomere group compared to the < 7 blastomere group with respect to single high-quality blastocyst transfer cycles. Conversely, these rates were similar in the two groups with respect to single low-quality blastocyst transfer cycles. These results were confirmed by multivariate logistic regression analysis. However, the miscarriage rate was higher in the < 7 blastomere group than in ≥ 7 group during low-quality blastocyst transfer cycles. These results suggested that day 3 blastomere number should be considered during single vitrified-warmed blastocyst transfer cycles. Thus, blastocsyts derived from ≥ 7 blastomere embryos are preferred when choosing the same quality blastocysts.

Cryostorage management of reproductive cells and tissues in ART: status, needs, opportunities and potential new challenges

Among the wide range of procedures performed by clinical embryologists, the cryopreservation of reproductive cells and tissues represents a fundamental task in the daily routine. Indeed, cryopreservation procedures can be considered a subspecialty of medically assisted reproductive technology (ART), having the same relevance as sperm injection or embryo biopsy for preimplantation genetic testing. However, although a great deal of care has been devoted to optimizing cryopreservation protocols, the same energy has only recently been spent on developing and implementing strategies for the safe and reliable storage and transport of reproductive specimens. Herein, we have summarized the content of the available guidelines, the risks, the needs and the future perspectives regarding the management of cryopreservation biorepositories used in ART.

Effect of exposed-to-air frequency of cryopreserved embryo on clinical outcomes of vitrified-warmed embryo transfer cycles: a retrospective analysis of 9,200 vitrified-warmed transfer cycles

BACKGROUND

Cryopreservation of embryos plays a major role in the in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatment. However, the storage condition of the cryopreserved embryo can change temporarily due to repeated retrieval of the embryo from the liquid nitrogen (LN2) tank during the practical application during cryopreservation. Whether the implantation potential of a cryopreserved embryo will be damaged when the cane containing it is temporarily exposed to air due to the transfer between the LN2 tank and LN2 container is yet to be elucidated. Also, whether the exposed-to-air frequency (EAF) of cryopreserved embryos influences the clinical outcomes is unclear.

OBJECTIVE

To investigate whether the EAF of cryopreserved embryo affects the clinical outcomes of vitrified-warmed embryo transfer.

METHODS

A total of 9200 vitrified-warmed embryo transfer cycles were included in this study. All cycles were divided into five groups according to different EAFs (2, 4, 6, 8, or ≥ 10). Post-warming survival rates and clinical outcomes, including implantation, clinical pregnancy and live birth rates were investigated. Kruskal-Wallis test and Pearson's chi-squared tests were used to compare the patient characteristics and clinical outcomes among the five groups. Furthermore, multivariate logistic regression analyses were conducted to investigate the association between EAF and clinical outcomes.

RESULTS

No significant differences were observed in the positive HCG rate, implantation rate and live birth rate (P > 0.05) among five EAF groups with respect to D3 embryo, D5 blastocyst and D6 blastocyst. Post-warmed survival rate of D3 embryos (P = 0.015) differed significantly among the five EAF groups, but it was not EAF-dependent. Although clinical pregnancy was different among the five groups with respect to D5 blastocyst (P = 0.042), multivariate logistic regression analysis adjusted for confounding variables suggested that EAF did not adversely affect clinical pregnancy or live birth.

CONCLUSION

These findings indicated that human vitrified embryos in the open system could be repeatedly retrieved from the LN2 tank without affecting the implantation potential of the embryo.

The effect of extended cryo-storage following vitrification on embryo competence: a systematic review and meta-analysis

PURPOSE

Few studies explored whether prolonged cryo-storage after vitrification affects embryo competence and perinatal outcomes. This systematic review and meta-analysis aims at highlighting any putative impact of cryo-storage duration on cryo-survival, miscarriage, live birth and major malformations.

METHODS

A systematic review was performed using MEDLINE (PubMed), ISI Web of Knowledge, Scopus and Embase databases up to June 2021. Data were combined to obtain a pooled OR, and meta-analysis was conducted using a random effects model. Out of 1,389 screened abstracts, 22 papers were assessed for eligibility, and 5 studies were included (N = 18,047 embryos). Prolonged cryo-storage was defined as > 12 months (N = 3389 embryos). Subgroup analysis was performed for untested vitrified cleavage stage embryos (N = 1739 embryos) and for untested and euploid vitrified blastocysts (N = 13,596 and 2712 embryos, respectively).

RESULTS

Survival rate, miscarriage, live birth and major malformation rates were all similar in the two groups.

CONCLUSION

These data further support the safety of long-term cryo-storage of human embryos beyond 12 months. This is reassuring for good prognosis patients with surplus embryos, couples seeking a second child from supernumerary embryos and women postponing the transfer for clinical or personal reasons.

Are commercial warming kits interchangeable for vitrified human blastocysts? Further evidence for the adoption of a Universal Warming protocol

PURPOSE

To study whether a new combination of different warming kits is clinically effective for vitrified human blastocysts.

METHODS

This is a longitudinal cohort study analysing two hundred fifty-five blastocysts warming cycles performed between January and October 2018. Embryos were vitrified using only one brand of ready-to-use kits (Kitazato), whereas the warming procedure was performed with three of the most widely used vitrification/warming kits (Kitazato, Sage and Irvine) after patient stratification for oocyte source. The primary endpoint was survival rate, while the secondary endpoints were clinical pregnancy, live birth and miscarriage rates.

RESULTS

We observed a comparable survival rate across all groups of 100% (47/47) in KK, 97.6% (49/50) in KS, 97.6% (41/42) in KI, 100% (38/38) in dKK, 100% (35/35) in dKS and 100% (43/43) in dKI. Clinical pregnancy rates were also comparable: 38.3% (18/47) in KK, 49% (24/49) in KS, 56.1% (23/ 41) in KI, 47.4% (18/38) in dKK, 31.4% (11/35) in dKS and 48.8% (21/ 43) in dKI. Finally, live birth rates were 29.8% (14/47) in KK, 36.7% (18/49) in KS, 46.3% (19/41) in KI, 36.8% (14/38) in dKK, 25.7% (9/35) in dKS and 41.9% (18/43) in dKI, showing no significant differences.

CONCLUSION

This study confirmed the efficacy of applying a single warming protocol, despite what the "industry" has led us to believe, supporting the idea that it is time to proceed in the cryopreservation field and encouraging embryologists worldwide to come out and reveal that such a procedure is possible and safe.

Clinical, obstetric and perinatal outcomes after vitrified-warmed euploid blastocyst transfer are independent of cryo-storage duration

RESEARCH QUESTION

The study aimed to retrospectively evaluate the impact of cryo-storage duration on clinical, obstetric and perinatal outcomes after vitrified-warmed euploid blastocyst transfer.

DESIGN

This was an observational study including 2688 vitrified-warmed euploid single blastocyst transfers that was conducted at a private IVF centre between May 2013 and March 2020. It included a total of 1884 women (age 38 ± 3 years) undergoing at least one transfer after preimplantation genetic testing for aneuploidies. The euploid blastocysts transferred were clustered into seven groups according to the cryo-storage duration between vitrification and warming: ≤60 days (n = 646; control group), 61-90 days (n = 599), 91-180 days (n = 679), 181-360 days (n = 405), 361-720 days (n = 144), 721-1080 days (n = 118) and >1080 days (n = 97). The primary outcome was the live birth rate (LBR) per transfer. The secondary outcomes were miscarriage rate, obstetric and perinatal issues. The data were adjusted for confounders through logistic or linear regressions.

RESULTS

A significantly lower LBR was reported for transfers performed within 91-180 days (n = 291/679, 42.9%; P = 0.017), 181-360 days (n = 169/405, 41.7%; P = 0.016) and 361-720 days (n = 57/144, 39.6%; P = 0.034) versus ≤60 days (n = 319/646, 49.4%). However, this was mainly due to top-quality embryos being transferred first when more euploid blastocysts were available, thereby leaving lower quality ones for subsequent procedures. Indeed, the multivariate odds ratios adjusted for confounders showed similar results across all cryo-storage duration clusters. No difference was reported also for all secondary outcomes.

CONCLUSIONS

Cryo-storage duration even beyond 3 years from blastocyst vitrification does not affect clinical, obstetric and perinatal outcomes.

Does longer storage of blastocysts with equal grades in a cryopreserved state affect the perinatal outcomes?

AIM

Although mammalian embryos could be preserved in liquid nitrogen for thousands of years in theoretical models, the viability of cryopreserved blastocyst with varying grades remains to be speculated. In this study, we aimed to determine whether the longer storage time of blastocysts with equal grades could negatively affect the perinatal outcomes.

MATERIALS AND METHODS

Single vitrified-warmed blastocyst was divided into four grades (AA, AB/BA, BB, BC/CB) according to the blastocyst score when freezing, and each grade of blastocyst was categorized into four storage duration categories: 28 days-1 year, 1-3 years, 3-5 years, and ≥5 years. Then the perinatal outcomes with different storage time were analyzed.

RESULTS

Our results revealed that for blastocysts with the same grade, the length of storage time had no statistical effect on blastocyst survival rate, clinical pregnancy/implantation rate, live birth rate, and abortion rate. In addition, more advanced developmental blastocyst could obtain better pregnancy outcomes regardless of the cryopreservation length. Similar neonatal outcomes were obtained over time.

CONCLUSIONS

Cryopreservation time could not negatively affect the perinatal outcomes of blastocysts with equal grades. Efficient blastocyst cryopreservation technology by vitrification can help older women obtain high-quality embryos at a young age.

Clinical and perinatal outcomes of fresh single-blastocyst-transfer cycles under an early follicular phase prolonged protocol according to day of trigger estradiol levels

Backgroud

This study’s objectives were to compare the clinical, perinatal, and obstetrical outcomes of patients with different estradiol (E₂) levels in fresh single-blastocyst-transfer (SBT) cycles under an early follicular phase prolonged regimen on the day of trigger.

Methods

We recruited patients in fresh SBT cycles (n = 771) undergoing early follicular phase prolonged protocols with β-hCG values above 10 IU/L between June 2016 and December 2018. Patients who met the inclusion and exclusion criteria were divided into four groups according to their serum E₂ level percentages on the day of trigger: <25^th, 25^th–50^th, 51^st–75^th, and >75^th percentile groups.

Results

Although the rates of clinical pregnancy (85.57% (166/194)), embryo implantation 86.60% (168/194), ongoing pregnancy (71.13% (138/194)), and live birth (71.13% (138/194)) were lowest in the >75th percentile group, we did not observe any significant differences (all P > 0.05). We used this information to predict the rate of severe ovarian hyperstimulation syndrome (OHSS) area under the curve (AUC) = 72.39%, P = 0.029, cut off value of E₂ = 2,893 pg/ml with the 75% sensitivity and 70% specificity. The 51^st–75^th percentile group had the highest rates of low birth weight infants (11.73% (19/162), P = 0.0408), premature delivery (11.43% (20/175), P = 0.0269), admission to the neonatal intensive care unit (NICU) (10.49% (17/162), P = 0.0029), twin pregnancies (8.57% (15/175), P = 0.0047), and monochorionic diamniotic pregnancies (8.57% (15/175); P = 0.001). We did not observe statistical differences in obstetrics complications, including gestational diabetes mellitus (GDM), gestational hypertension, placenta previa, premature rupture of membranes (PROM), and preterm premature rupture of membranes (PPROM).

Conclusion

We concluded that serum E₂ levels on the day of trigger were not good predictors of live birth rate or perinatal and obstetrical outcomes. However, we found that high E₂ levels may not be conducive to persistent pregnancies. The E₂ level on the day of trigger can still be used to predict the incidence of early onset severe OHSS in the fresh SBT cycle.

A New Day 4 Grading System to Assess Embryo Quality in Frozen Embryo Transfer Cycles

To present a new day 4 (D4) embryo grading system to assess embryos in frozen-thawed embryo transfer (FET) cycles. A new grading system (grades A-E) was developed from the 2011 ESHRE Istanbul Consensus for D4 embryos in FET cycles. Embryos with complete compaction were classified as grade A; those with partial compaction were assigned as grade B; and those without compaction were classified as grades C, D, and E according to their different blastomere number ratio (BNR; number of embryo blastomeres on D4/number of embryo blastomeres on D3, D4/D3). Embryos with a BNR of ≥ 1.5 were defined as grade C, those with a BNR of ≥ 1.2 and < 1.5 were defined as grade D, and those with a BNR of ≥ 1.0 and < 1.2 were defined as grade E. Using this proposed grading model, 5460 embryos with known implantation data were retrospectively analyzed after D4 transfer in FET cycles. The transferred embryos exhibited a similar declining trend in implantation and live birth rates from the top grade A to the lowest grade E. The in vitro fertilization group showed increased implantation rates of grade B and E embryos compared with the intracytoplasmic sperm injection group (grade B: 41.99%, 34.63%, χ² = 5.84, p < 0.05 and grade E: 18.98%, 14.08, χ² = 75.62, p < 0.01). Receiver-operating characteristic analysis revealed that our proposed model predicted the implantation outcomes and live birth rates of all embryos (area under the curve = 0.65; 95% confidence interval [CI],0.63-0.66; p < 0.01 and AUC = 0.73; 95%CI, 0.65-0.84; p < 0.001, respectively). This study demonstrates that the new grading system provided by us can be a useful tool for assisting embryo selection via changes in embryo morphology. D4 embryo transfer provides a simple and applicable method for FET cycles in daily practice.

Associations between a new day 4 embryo grading system and implantation rates in frozen embryo transfer (FET) cycles

The purpose of this study is to present a new day 4 (D4) embryo grading system for the assessment of embryos in frozen-thawed embryo transfer (FET) cycles.A new grading system (grades A-E) was modified from the 2011 ESHRE Istanbul Consensus for D4 embryos in FET cycles. In total, we retrospectively analyzed 5640 embryos with known implantation data after D4 transfer in FET cycles by using this proposed grading model.The transferred embryos exhibited a similar declining trend in implantation rates from the top grade A to the lowest grade E. The implantation rates of grade B and E embryos in the in vitro fertilization group were significantly higher than that in the intracytoplasmic sperm injection group (grade B: 41.82%, 35.23%, χ = 5.85, P < .05 and grade E: 18.53%, 14.81, χ = 76.86, P < .01, respectively). The receiver operating characteristic analysis showed that our proposed model predicted the implantation outcomes of all embryos (area under the ROC curve = 0.65; 95% CI, 0.63-0.66; P < .01).This study demonstrated that the new grading system provided by us turned out to be a useful tool in assisting embryo selection via embryo morphological changes, and D4 embryo transfer provided a simple and applicable method for a daily routine in FET cycles.

Perinatal and obstetric outcomes in singleton pregnancies following fresh versus cryopreserved blastocyst transfer: a meta-analysis

The transfer of cryopreserved blastocysts is increasing in IVF centres. However, little is known about the perinatal and obstetric outcomes of this procedure. In an attempt to further elucidate these issues, a systematic review and meta-analysis was conducted to compare cryopreserved transfer with fresh blastocyst embryo transfer. The results show that the risk of both preterm (odds ratio [OR] 0.89, 95% confidence interval [CI] 0.80-0.99, P = 0.04) and low birthweight births (OR 0.82, 95% CI 0.68-0.99, P = 0.04) was significantly lower after cryopreserved blastocyst transfer than after fresh blastocyst transfer. The rate of large for gestational age births was significantly higher (OR 1.68, 95% CI 1.55-1.82, P < 0.00001) and the rate of small for gestational age births significantly lower (OR 0.59, 95% CI 0.54-0.65, P < 0.00001) after cryopreserved blastocyst transfer. The transfer of cryopreserved blastocysts was associated with a significantly lower risk of placental abruption (OR 0.58, 95% CI 0.40-0.83, P = 0.003) but a significantly higher risk of Caesarean section (OR 1.21, 95% CI 1.01-1.43, P = 0.03). In conclusion, the perinatal and obstetric outcomes associated with the transfer of cryopreserved blastocysts differ from those associated with fresh blastocyst transfer.

Which is better for mothers and babies: fresh or frozen-thawed blastocyst transfer?

BACKGROUND

In recent years, there have been many reports on the pregnancy outcomes of fresh blastocyst transfer (BT) and frozen-thawed BT, but the conclusions are controversial and incomplete. To compare the pregnancy outcomes, maternal complications and neonatal outcomes of fresh and frozen-thawed BT in the context of in vitro fertilization or intracytoplasmic sperm injection (IVF/ICSI) cycles, we conducted a meta-analysis.

METHODS

A meta-analysis was conducted by searching the PubMed, Embase, and Cochrane Library databases through May 2020. Data were extracted independently by two authors.

RESULTS

Fifty-four studies, including 12 randomized controlled trials (RCTs), met the inclusion criteria. Fresh BT was associated with a lower implantation rate, pregnancy rate, ongoing pregnancy rate, and clinical pregnancy rate and higher ectopic pregnancy rate than frozen-thawed BT according to the results of the RCTs. The risks of moderate or severe ovarian hyperstimulation syndrome, placental abruption, placenta previa and preterm delivery were higher for fresh BT than for frozen-thawed BT. The risk of pregnancy-induced hypertension and pre-eclampsia was lower for fresh BT; however, no significant differences in risks for gestational diabetes mellitus and preterm rupture of membrane were found between the two groups. Compared with frozen-thawed BT, fresh BT appears to be associated with small for gestational age and low birth weight. No differences in the incidences of neonatal mortality or neonatal malformation were observed between fresh and frozen-thawed BT.

CONCLUSIONS

At present there is an overall slight preponderance of risks in fresh cycles against frozen, however individualization is required and current knowledge does not permit to address a defintive response.

A freeze-all strategy does not increase live birth rates in women of advanced reproductive age

RESEARCH QUESTION

Does a freeze-all strategy improve live birth rates in women of different age groups?

DESIGN

Retrospective cohort study of 1882 first embryo transfer cycles, performed between January 2013 and December 2015. Reproductive outcomes between fresh (FRESH) or frozen (FROZEN) embryo transfers were compared in patients stratified by age: < 35, between 35 and 38, or > 38 years. Student's t test for independent samples and χ² analyses were used as needed. A multivariable logistic regression analysis was performed adjusting for age, triggering drug, number of retrieved oocytes, number of transferred embryos, and percentage of top-quality embryos.

MAIN RESULTS AND THE ROLE OF CHANCE

Live birth rates (LBR) were significantly higher for FROZEN in the < 35 years group (43.7% vs 24%; p < 0.001). In both the 35-38 and > 38 years groups, LBR for FROZEN vs FRESH were not statistically different (30.9% in the FROZEN group vs 29.3% in the FRESH group, p = 0.70, and 19.8% in the FROZEN group vs 12.7% in the FRESH group, p = 0.07, respectively). The multivariate analysis found a significantly positive effect of performing FROZEN on LBR in the younger group (OR 2.46, 95% CI 1.31-4.62; p = 0.005) but had no impact in women between 35 and 38 years (OR 1.01, 95% CI 0.55-1.83; p = 0.98) or older (OR 0.96, 95% CI 0.43-2.13; p = 0.92).

CONCLUSIONS

Performing a freeze-all strategy seems to result in better reproductive outcomes when compared with a fresh ET in women under 35 years, with no significant impact on older women.

Survival, re-expansion, and pregnancy outcome following vitrification of dromedary camel cloned blastocysts: A possible role of vitrification in improving clone pregnancy rate by weeding out poor competent embryos

There is a clinical demand for efficient cryopreservation of cloned camel embryos with considerable logistic and economic advantage. Vitrification of in vivo derived embryos has been reported in camels, but there is no study on vitrification of cloned embryos. Moreover, whether characteristic differences between cloned and in vivo derived embryos imply different vitrification requirement is unresolved. Here, we compared survival, re-expansion and pregnancy rates of cloned embryos vitrified using two commercial vitrification kits (Cryotec and Kitazato), developed basically for human embryos, and a vitrification protocol developed for in vivo camel embryos (CVP). Cloned embryos responded dynamically to vitrification-warming steps in commercial kits, with a flat shrinkage in the final vitrification solution and a quick re-expansion to the original volume immediately after transferring to the isotonic warming solution. Contrarily, full shrinkage was not observed in CVP method, and majority of embryos were still collapsed post-warming. The immediate re-expansion was highly associated and predictive of higher survival and total cell number, and also better redox state of embryos vitrified by Cryotec and Kitazato kits compared to CVP method. Importantly, while 30% blastomere loss, verified by differential dye exclusion test, was tolerated in vitrified embryos, >50% blastomeres loss in non-expanded blastocysts implied the minimal essential cell survival rate for blastocoelic cavity re-expansion in vitrified cloned camel blastocysts, irrespective of vitrification method. A protocol-based exposure of embryos to cryoprotectants indicated that cryoprotectant toxicity, per se, may not be involved in lower cryosurvival of embryos in CVP vs. Cryotec and Kitazato. The initial pregnancy rates were numerically higher in Cryotec and Kitazato frozen transfers compared to fresh transfer (56.3, 60 and 33.3%, respectively), and importantly, a higher percentage of established pregnancies in vitrified groups passed the critical 3 months period of early embryonic loss compared to sibling fresh clone pregnancies (50, 40, and 10%, respectively). Results confirmed the suitability of Cryotec and Kitazato kits for vitrification of cloned camel embryos and that vitrification may improve pregnancy outcome by weeding out poor competent embryos.

Large for gestational age and macrosomia in singletons born after frozen/thawed embryo transfer (FET) in assisted reproductive technology (ART)

Increase in success rates with frozen embryo transfer (FET) and reduced risk of ovarian hyperstimulation syndrome (OHSS) and multiple pregnancies has lead to a steady rise in FET. Further, FET is associated with lower risk of prematurity and low birth weight in singletons, when compared with fresh transfer. However, there is a growing concern of increased risk of large for gestational (LGA) and/or macrosomic children after FET. Macrosomic/LGA births have a higher risk of cesarean section, fetal hypoxia and stillbirth. Improvements in cryopreservation techniques indicate that FET is a trend expected to continue and a freeze-all policy has lately been introduced. With this review, we wished to evaluate the association between FET and LGA and/or macrosomia. We searched electronic databases on January 12, 2018. Ten studies on LGA and six studies on macrosomia were eligible for meta-analysis. We found that the risk of LGA in FET was increased 1.5-fold (AOR = 1.50 95% CI 1.44-1.57 p < 0.001) compared to fresh cycles and 1.3-fold (AOR = 1.31 95% CI 1.20-1.43 p < 0.001) compared to natural conception (NC). Similarly we found a 1.7-fold increased risk of macrosomia in FET compared to fresh transfer (AOR = 1.71 95% CI 1.59-1.83 p < 0.001) and a 1.4-fold increased risk compared to NC (AOR = 1.42 95% CI 1.17-1.71 p < 0.001). Whether the increased risk of LGA and macrosomia is associated with higher long-term health risks remains unknown. Future studies should explore epigenetics modifications in children born after FET and predictors of long-term diseases need to be examined further with longitudinal studies.

Frozen blastocyst transfer reduces incidence of ectopic pregnancy compared with fresh blastocyst transfer: a meta-analysis

BACKGROUND

Ectopic pregnancy (EP) is the main cause of maternal death during early pregnancy. Blastocyst transfer (BT) reduces EP rates compared with cleavage stage embryo transfer (ET), and frozen ET reduces EP rates compared with fresh ET. However, data comparing the EP rate of fresh BT and frozen BT are limited. The objective of this meta-analysis was to determine whether frozen BT decreases the EP rate compared with fresh BT.

MATERIALS AND METHODS

PUBMED, EMBASE, and Cochrane Library databases were searched for papers with no limitation on language and publication year. A systemic literature search identified 14 studies which met the inclusion criteria for further analysis. EP rate is our only outcome measure. All statistical analyses were carried out using RevMan software [version 5.3]. Random effects models were chosen to calculate the odds ratio (OR).

RESULTS

Fourteen retrospective studies (n = 251,762 cycles) were finally analyzed, including 154,214 and 97,548 cycles undergoing fresh and frozen BT, respectively. Compared with fresh BT, the frozen BT was associated with an decrease in EP rate [OR = 1.79; 95% confidence interval (CI) = 1.37-2.34, heterogeneity was 71%], the EP rate was 1.74% (2683/154,214 pregnancies) for fresh BT and 0.97% (949/97,548 pregnancies) for frozen BT. The number of embryos transferred in subgroup analysis found that the incidence of EP in frozen BT is lower than fresh BT (OR = 1.62; 95% CI = 1.38-1.91), the EP rate was 1.2% (206/16,610 pregnancies) for one fresh BT and 0.8% (153/19,569 pregnancies) for one frozen BT, also the EP rate was 1.9% (78/4043 pregnancies) for two fresh BT and 1.1% (19/1790 pregnancies) for two frozen BT.

CONCLUSIONS

Our meta-analysis found that frozen BT was associated with an decrease in EP rate compared with fresh BT in IVF/ICSI patients. We also found that a single frozen BT is the better choice as a method to reduce the incidence of EP.

High implantation and clinical pregnancy rates with single vitrified-warmed blastocyst transfer and optional aneuploidy testing for all patients

This study reports the results of a 2-year long IVF programme ('One by One') in which all patients (median age 40 years; range 27-45 years) were offered preimplantation genetic testing for aneuploidy (PGT-A) and had all blastocysts vitrified (freeze-only), followed later by single vitrified-warmed blastocyst transfer (vSET) in managed cycles. Between January 2016 and December 2017, a total of 155 patients started 222 treatment cycles and 99 (45%) cycles resulted in one or more vitrified blastocysts (untested or with normal copy number for all chromosomes) available for transfer. Seventeen patients (11%) aged ≤35 years opted out of PGT-A. Over this period, 85 vSETs in 74 patients resulted in an implantation rate of 80% (68/85) and a singleton clinical pregnancy rate of 66% (56/85). Cumulative live birth rates will not be known for 1-2 years. Nevertheless, these high success rates with vSET confirm larger studies using selected patients and are likely to deliver similar, if not higher, live birth rates per cycle started than rates typically reported in national registries with conventional IVF and transfer of one or more fresh and/or frozen embryos.

Single fresh blastocyst transfer or single cryopreserved-thawed blastocyst transfer: which is preferable for infertile patients in IVF/ICSI cycles? A meta-analysis

PURPOSES

Nowadays, an increasing number of studies have proposed single embryo transfer (SET), especially single blastocyst transfer (SBT). To compare the clinical outcomes of single fresh blastocyst transfer (BT) and single cryopreserved-thawed BT in patients undergoing in vitro fertilization or intracytoplasmic sperm injection (IVF/ICSI) cycles.

METHODS

The PubMed, Embase, and Cochrane Library databases were searched from the start dates until February 2018. The primary outcomes were clinical pregnancy rate (CPR) and embryo implantation rate (IR). The secondary outcomes were multiple pregnancy rate (MPR), live birth rate (LBR), and miscarriage rate (MR). Using the Mantel-Haenszel random effects model to analyze summary risk ratio (RR) with 95% confidence intervals (CIs). Statistical heterogeneity scores were assessed with the standard Cochrane's Q test and I² statistic.

RESULTS

In total, eight studies (two prospective studies, six retrospective studies) were included in our analysis. There was no statistically significant difference regarding clinical pregnancy (RR = 1.18, 95% CI = 0.91-1.55) and embryo implantation (RR = 1.04, 95% CI = 0.77-1.41). Regarding secondary outcomes, there was no significant difference regarding miscarriage (RR = 0.79, 95% CI = 0.60-1.03) and multiple pregnancy (RR = 1.23, 95% CI = 0.75-2.04). However, single fresh BT is associated with an increased live birth (RR = 1.28, 95% CI = 1.05-1.57) compared with single cryopreserved-thawed BT.

CONCLUSIONS

In summary, this meta-analysis supports the hypothesis that single cryopreserved BT might not be the best choice compared with single fresh BT in patients undergoing IVF/ICSI cycles.

Thawed embryo transfer and ectopic pregnancy: a meta-analysis

PURPOSE

To examine whether thawed embryo transfers can reduce the rate of EP.

METHODS

The PubMed, EMBASE, Cochrane Library databases and two randomized controlled trials registration centers were thoroughly searched until March 2017. The clinical outcomes of IVF/ICSI cycles were compared between thawed and fresh embryo transfer.

RESULTS

Twenty-one articles were included in this meta-analysis. There were 801,464 pregnancies totally (thawed-ET: n = 158,967, fresh-ET: n = 642,497). The ectopic pregnancy rate was significantly lower in the group of thawed-ET than that in the group of fresh-ET (OR 0.69, 95% CI 0.57-0.82; I² = 83%). We subdivided the data into subgroups for D3 embryo transfer and D5 embryo transfer. We also found that the ectopic pregnancy rate was significantly lower with thawed-ET on D3 than that with fresh-ET (OR 0.67, 95% CI 0.53-0.85; I² = 0%). The risk of ectopic pregnancy was significantly decreased with thawed-ET on D5 than that with fresh-ET (OR 0.57, 95% CI 0.50-0.64; I² = 45%).

CONCLUSION

Our results indicate that in contrast to fresh embryo transfers, thawed D3 or D5 embryo transfers can reduce the rate of EP.

Frozen embryo transfer can be performed in the cycle immediately following the freeze-all cycle

PURPOSE

In this study, we investigated whether the time interval between oocyte retrieval and frozen embryo transfer (FET) affected the live birth (LB) rates of human segmented-IVF cycles.

METHOD

A total of 1338 ICSI freeze-all cycles were performed between February 2015 and January 2016, with 1121 FET cycles being retrospectively analyzed. All vitrified-warmed blastocyst transfers were performed in artificial FET cycles, using gonadotropin-releasing hormone (GnRH) agonist downregulation and oral estrogen endometrial preparation. The primary outcome measure was LB. Cycles were investigated in oocyte retrieval-to-FET interval groups of 32-46, 47-61, 62-76, 77-91, and ≥ 92 days, with the 47-61-day group used as the reference group.

RESULTS

There were no significant differences in LB rates between the groups in the overall analysis, as well as, in sub-analyses investigating LB in terms of single blastocyst transfer (SBT), trigger type (GnRH agonist, triggers including hCG), oocyte number (≤ 5 and ≥ 15), and maternal age (> 35 years).

CONCLUSION

The present study showed that it is feasible to perform transfers 36 days after oocyte retrieval and that delaying FET in freeze-all beyond the cycle immediately following oocyte retrieval does not increase LB rates.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Effect of different artificial shrinkage methods, when applied before blastocyst vitrification, on perinatal outcomes

BACKGROUND

In recent years, single blastocyst transfer combined with vitrification has been applied widely, which can maximize the cumulative pregnancy rate in per oocyte retrieval cycles and minimize the multiple pregnancy rate. Thus, the guarantee for these is the effectiveness of vitrified blastocyst. Studies has shown that AS of the blastocoel cavity prior to vitrification can reduce injuries, increase the thawed blastocyst survival rate and implantation rate. Several AS methods have been established. However, only a few studies have compared the effectiveness and safety of these AS methods. In this study, we aimed to compare the clinical outcomes and neonatal outcomes in FET cycles with single blastocyst that were artificially shrunk before vitrification by either LAS or MNAS method.

METHODS

A retrospective comparative study of FET cycles in infertile patients which were at our clinic between January 2013 and December 2014. These FET cycles were divided into two groups by the shrinking methods used before vitrification and the clinical and neonatal outcomes were assessed.

RESULTS

There were no statistically differences in blastocyst survival rates (95.40% vs 94.05%, P > 0.05) between the LAS and MNAS groups. However, compared with MNAS, LAS improved the warmed blastocyst implantation/clinical pregnancy rate (60.82% vs 54.37%, P < 0.05), live birth rate (50.43% vs 45.22%, P < 0.05) and also increased the monozygotic twin rate (4.07% vs 1.73%, P < 0.05). There were no differences in the average gestational weeks (38.83 ± 1.57 vs 38.74 ± 1.75), premature birth rate (0.30% vs 0.49%), average birth weight (3217.89 ± 489.98 g vs 3150.88 ± 524.03 g), low birth weight rate (5.60% vs 8.63%) and malformation rate (0.59% vs 0.48%) (P > 0.05).

CONCLUSIONS

No significant differences in neonatal outcomes were observed, while in clinical outcomes, LAS improved the warmed blastocyst implantation/clinical pregnancy rate and live birth rate markedly, there was also an increased risk of monozygotic twin pregnancies.

A successful pregnancy using completely immotile but viable frozen-thawed spermatozoa selected by laser

The aim of this study was to report a successful pregnancy using completely immotile frozen-thawed spermatozoa selected by laser. A single laser shot was used to detect the presence of viable immotile spermatozoa in fresh and frozen-thawed testicular spermatozoa. The viability rate was 55.8% after the laser detection, and cryopreservation was carried out immediately. The thawing test was performed on the day of oocyte pick-up, and no motile sperm were observed after extending the culture for another 4 hours, while a survival rate of 39.8% was detected using the laser. In all, five mature oocytes were injected, resulting in four cases of normal fertilization (80%) on day 1. Further, two high-quality day 3 embryos were transferred, which resulted in a singleton pregnancy. Our study demonstrates that completely immotile spermatozoa are worth cryopreserving for further intracytoplasmic sperm injection, which provides a new insight into male fertility preservation in cases of completely immotile spermatozoa.

Influence of storage time on vitrified human cleavage-stage embryos froze in open system

BACKGROUND

During in vitro fertilization, rapid growth of vitrification and liquid nitrogen storage of embryos have been well characterized. However, the effect of storage time on vitrified cleavage-stage embryos in an open system is poorly understood.

AIMS

To investigate the influence of storage time on the survival and pregnancy outcomes of vitrified human cleavage-stage embryos froze and stored in an open system.

METHODS

A retrospective study of 786 vitrified-warmed cycles of 735 patients was performed from January 2013 to October 2013. The cycles were divided into five groups according to storage time: 1-3 months, 4-6 months, 7-12 months, 13-24 and 25-60 months. The clinical outcomes of cycles with different storage time were analyzed.

RESULTS

There were no significant differences of the survival rate, clinical pregnancy outcomes, birth rate, gestational weeks and singleton birthweights at various storage times.

CONCLUSION

For vitrified embryos froze and stored in an open system, the storage time would not influence the survival rate and pregnancy outcomes by storage time up to 5 years.

Embryo stage of development is not decisive for reproductive outcomes in frozen-thawed embryo transfer cycles

Objective

To evaluate if the outcomes of IVF/ICSI in frozen-thawed embryo transfer and fresh embryo transfer cycles differ in relation to cleavage and blastocyst stages.

Methods

Retrospective cohort study to compare IVF/ICSI outcomes between fresh embryo transfer and frozen-thawed embryo transfer cycles, according to the stage of embryo development. Analysis was carried out on 443 consecutive embryo transfer cycles performed between January 1st and December 31st, 2014. Women aged up to 38 and submitted to embryo transfer cycles with fresh (n = 309) or frozen-thawed (n = 134) embryos at a private center for assistance in human reproduction were considered for analysis. Results in each group were stratified according to the stage of embryo development: cleavage stage and blastocyst stage. Main outcome measures were implantation rate, clinical pregnancy rate, ongoing pregnancy rate and live birth rate per cycle.

Results

In the fresh embryo transfer group, for cleavage stage versus blastocyst stage, respectively, implantation rates were 22% and 47% (p = 0.0005); clinical pregnancy rates were 34% and 64% (p = 0.0057); the ongoing pregnancy rates were 30% and 61% (p = 0.0046) and live birth rates were 28% and 55% (p = 0.0148). There were no significant differences in the rates between cleavage and blastocyst stages in the frozen-thawed group, neither between fresh and frozen-thawed cleavage embryo transfers nor between fresh and frozen-thawed blastocyst transfers.

Conclusion

Our results confirm that blastocyst transfer is better than cleavage stage in fresh embryo transfer cycles. In frozen-thawed cycles, cleavage or blastocyst stages seem to offer similar reproductive outcomes.

Concurrent oocyte retrieval and hysteroscopy: a novel approach in assisted reproduction freeze-all cycles

In this matched-controlled study (n = 300), the effect of hysteroscopic surgery performed concurrently with oocyte retrieval on the reproductive outcomes of intracytoplasmic sperm injection (ICSI) freeze-all cycles was investigated in patients screened for intrauterine anomalies. Conventionally, hysterscopic surgery is performed in a different cycle from IVF, delaying treatment completion and increasing patient anxiety. One hundred and fifty patients who had hysteroscopic surgery concurrently with oocyte retrieval (hysteroscopy group) in ICSI freeze-all cycles were matched according to age and oocyte number with 150 ICSI freeze-all cycles, in which the patients required no hysteroscopy (control group). In the hysteroscopy group, hysteroscopy was performed for diagnostic (n = 5) and therapeutic (n = 145) purposes. Blastocyst culture and Cryotop vitrification was performed in both groups. Frozen embryo transfer (FET) was successfully performed in the hysteroscopy group from 35 days after oocyte retrieval. No significant differences were observed for implantation, pregnancy, clinical pregnancy and early pregnancy loss rates in the hysteroscopy and control groups (48.9%, 72.0%, 61.3% and 14.8% versus 48.3%, 75.3%, 64.7% and 14.3%, respectively). Performing hysteroscopic surgery concurrently with oocyte retrieval in a segmented-IVF programme has no negative impact on reproductive outcomes, increases efficiency, and provides patients with low-risk treatment.

Segmented ART - The new era in ART?

Currently up to 4% of infants born in developing countries are conceived through assisted reproductive technology (ART). Even though most of these conceptions occur and progress without complications, ART procedures and processes may increase iatrogenesis through complications in - and after conception. We herein review and discuss the clinically and scientific implications and evidence of iatrogenesis, and show how the evolution in ART technologies and procedures has led to the current presumption that frozen embryo transfer might be a more optimal strategy than fresh embryo transfer, in terms of not only reproduction, but also of maternal and fetal outcomes. There is increasing scientific evidence to support the notion that controlled ovarian stimulation could induce significant changes to the endocrine profile of a reproductive cycle, especially to the reproductively important early luteal phase. These changes may not only have a negative effect on implantation and early placentation, but also on the mother, the fetus, and the infant. The overt consequences of controlled ovarian stimulation include ovarian hyperstimulation syndrome, reduced embryo implantation, increased ectopic pregnancy, and altered placentation and fetal growth. The cumulative scientific evidence from this review suggests that GnRHa trigger in segmented ART might constitute the future routine treatment regimen for IVF patients, providing a safe, effective, and patient friendly treatment.

Use of the CryoPredict algorithm to predict live birth from cryopreserved embryos

BACKGROUND

Currently, the viability of cryostored blastocysts that are subsequently re-warmed is determined via the percentage of cell survival. However, the large number of cells that forms the blastocyst can make this estimate difficult and unreliable. Studies have shown that fast re-expanding blastocysts have superior pregnancy rates.

AIM

To determine whether the degree and speed of blastocoele re-expansion following cryopreservation and warming correlate with rates of live birth.

MATERIALS AND METHODS

A retrospective cohort study of 757 frozen embryo transfer cycles over a 4-year period at Royal Prince Alfred Hospital, Sydney. Clinical and embryology notes were retrieved. Details regarding patient demographics, stimulation cycle from which embryos were derived, frozen embryo transfer cycles, embryology and pregnancy outcomes were recorded.

RESULTS

Female (P = 0.01) and male age (P = 0.02) at the time of embryo creation were inversely associated with live birth. Fertilisation method (P = 0.03), embryo type at cryopreservation (P = 0.009), embryo grade at cryopreservation (P < 0.0001), percentage of cell survival post-thaw (P < 0.0001) and the degree of re-expansion (P = 0.003) were the IVF and embryology factors significantly associated with live birth. A predictive model (CryoPredict) was created in order to individualise the probability that the transfer of a given embryo would result in live birth.

CONCLUSIONS

The degree and speed of blastocoele re-expansion postcryopreservation and subsequent warming can be used in conjunction with other parameters to predict live birth.

Higher clinical pregnancy rates from frozen-thawed blastocyst transfers compared to fresh blastocyst transfers: a retrospective matched-cohort study

PURPOSE

The purpose of this matched-cohort study was to assess endometrial receptivity to blastocyst implantation in fresh embryo transfer by comparing implantation outcomes of fresh embryo transfer with frozen embryo transfer, where two blastocysts of good quality were transferred in good prognosis patients.

METHOD(S)

Fresh embryo transfer from intracytoplasmic sperm injection cycles and artificial frozen embryo transfer cycles performed from January 2012 to December 2013 at a private clinic were retrospectively analyzed and the pregnancy, clinical pregnancy, and implantation rates statistically compared. Cycles were stratified and matched according to the blastocyst expansion grade (grade 2, 3, 4, or 5) of the two blastocysts transferred. Five hundred ninety-eight fresh embryo transfer cycles were matched with 545 frozen embryo transfer cycles across four blastocyst cohorts.

RESULT(S)

In this study of 1143 blastocyst transfer cycles, fresh embryo transfer resulted in reduced pregnancy, clinical pregnancy, and fetal heart implantation rates in all four blastocyst cohorts. The fetal heart implantation rates for fresh embryo transfer ranged from 16.7 % in the grade 2 to 47.3 % in the grade 5 cohort, compared to 23.1 % in the grade 2 to 57.4 % in the grade 5 cohort for frozen embryo transfer. The trends in increasing pregnancy outcomes relative to increasing blastocyst expansion were similar in fresh embryo transfer and frozen embryo transfer.

CONCLUSION(S)

Blastocysts of good quality transferred in frozen embryo transfer had a significantly greater chance of implantation and clinical pregnancy compared to blastocysts of matched quality transferred in fresh embryo transfer, suggesting reduced endometrial receptivity in fresh embryo transfer.

Perinatal outcomes after fresh versus vitrified-warmed blastocyst transfer: retrospective analysis

OBJECTIVE

To investigate the possible effect of controlled ovarian stimulation on the perinatal outcomes of assisted reproductive technology pregnancies, by comparing the outcomes from fresh ET with frozen ET (FET) with blastocysts of similar quality.

DESIGN

Retrospective observational study.

SETTING

Private fertility center.

PATIENT(S)

Seven hundred eighty-four fresh transfers and 382 vitrified-warmed double blastocyst transfers.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Miscarriage, perinatal mortality, preterm delivery, live birth, live-birth weights, and gestational age of live births.

RESULT(S)

FET resulted in higher implantation rates (51.5% vs. 40.6%), higher live-birth rates per transfer (56.8% vs. 44.3%), and lower ectopic pregnancy rates (0.32% vs. 1.80%). FET pregnancies also had higher day 14 βhCG levels per implantation (148.2 vs. 176.2 IU/L) and higher infant birth weights (singletons Δ109.4 g, twins Δ124 g). Female infants benefitted the most in terms of birth weight. Miscarriage, premature delivery, perinatal morbidity, and live birth per pregnancy were all nonsignificantly different between fresh ET and FET.

CONCLUSION(S)

Clinically significant differences between the peri-implantation and perinatal outcomes of fresh ET and FET suggest better endometrial receptivity and placentation in FET cycles.

[Contribution of embryo vitrification procedure to ART efficiency]

This work aims to show, from data available in the literature and our own experience, how embryos' vitrification change and/or improve the management of infertile couples. In all, 652 cycles of frozen-thawed embryo transfers (FET) following vitrification were prospectively included and compared with 1126 FETs from slow freezing (SF) method. Primary end points were the (i) survival rate (SR) (% of embryos with>50% post-thaw intact blastomeres) and (ii) intact survival rate (ISR) (% of embryos with 100% post-thaw intact blastomeres). Secondary end point was the clinical pregnancy rate (CPR) defined as the presence of an intra uterine gestational sac with positive foetal heart beat. In all, 1097 and 2408 embryos have been thawed following vitrification and SF, respectively. We observed a highly significant increase of SR and ISR respectively when thawing concerned vitrified embryos rather than those from SF method (97.0% vs. 72.7%, P<10(-4); 91.5% vs. 49.8%, P<10(-4)). Furthermore, CPR were of 26.5% (73/652) and of 18.1% (204/1126) following FETs performed after vitrification or SF and thawing (P=0.0002), respectively. At the blastocyst stage, ISR was significantly improved following vitrification compared to SF (94.5% vs. 21.4%, P<10(-4)). In the study period, vitrification (i) reduced the mean number of fresh transferred embryos (1.5 vs. 1.6; P=0.08) and (ii) increased the rate of FETs at the blastocyst stage when compared with the control period (18.1% vs 2.5%., P<10(-4)). Embryo vitrification preserves all embryos from an ART cycle because of its excellent results regarding ISR at all stages of embryo development. This procedure allows a significant increase of pregnancy rates after thawing. In addition, there is a trend for increasing ART cycles performed using extended culture embryo and vitrification. The expected improvement of the cumulative birth rate at the blastocyst stage following vitrification remains to be demonstrated in a prospective randomized study.

Multiple pregnancy, fetal reduction and selective termination

The avoidance of twin or higher-order multiple pregnancies is in the best interest of families, medical practitioners and health services, given the health hazards and costs associated with higher-order multiples. This commentary explores the background to and ideas in the paper by Legendre et al., (2013), which makes the case for separate consideration of the various issues around selective termination of a multiple pregnancy and fetal reduction. The exploration does so mainly within the context of UK law and practice, but has international relevance. The responsibilities of health professionals for putting many of these women in the difficult position of having to make a decision about selective termination or fetal reduction is critically reviewed. The imperative must be for health professionals to reduce the need for women to have to make these difficult choices. In these circumstances, I argue that the differences in motivation and emotional burden between the two situations may be less clear cut, and are less salient, in practice than Legendre et al. conclude from their theoretical approach to the issues.

Massively parallel sequencing for chromosomal abnormality testing in trophectoderm cells of human blastocysts

Preimplantation genetic diagnosis and screening are widely accepted for chromosomal abnormality identification to avoid transferring embryos with genetic defects. Massively parallel sequencing (MPS) is a rapidly developing approach for genome analysis with increasing application in clinical practice. The purpose of this study was to use MPS for identification of aneuploidies and unbalanced chromosomal rearrangements after blastocyst biopsy. Trophectoderm (TE) samples of 38 blastocysts from 16 in vitro fertilization cycles were subjected to analysis. Low-coverage whole genome sequencing was performed using the Illumina HiSeq2000 platform with a novel algorithm purposely created for chromosomal analysis. The efficiency of this MPS approach was estimated by comparing results obtained by an Affymetrix single-nucleotide polymorphism (SNP) array. Whole genome amplification (WGA) products of TE cells were detected by MPS, with an average of 0.07× depth and 5.5% coverage of the human genome. Twenty-six embryos (68.4%) were detected as euploid, while six embryos (15.8%) contained uniform aneuploidies. Four of these (10.5%) were with solely unbalanced chromosomal rearrangements, whereas the remaining two embryos (5.3%) showed both aneuploidies and unbalanced rearrangements. Almost all these results were confirmed by the SNP array, with the exception of one sample, where different sizes of unbalanced rearrangements were detected, possibly due to chromosomal GC bias in array analysis. Our study demonstrated MPS could be applied to accurately detect embryonic chromosomal abnormality with a flexible and cost-effective strategy and higher potential accuracy.