169 EMBRYO TRANSFER OF SEXED/VITRIFIED IVF EMBRYOS IN CATTLE: PREGNANCY COMPARISON AFTER SINGLE AND DOUBLE TRANSFERS

2010 ◽  
Vol 22 (1) ◽  
pp. 243
Author(s):  
A. S. Castro ◽  
J. Xu ◽  
D. C. Pereira ◽  
L. Ferre ◽  
N. Diaz ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Fetal Loss ◽  
Hatching Rate ◽  
Ultrasound Monitoring ◽  
General Linear Model Analysis ◽  
Transfer Group

Advancement in sperm sorting technology combined with vitrification of in vitro produced bovine embryos will promote cattle breeding and production. The objective of this study was to evaluate pregnancy and embryo loss after embryo transfer (ET) of sexed/vitrified embryos with one bilaterally (double transfer, 2 embryos) v. ipsilaterally (single transfer, 1 embryo) into the recipient. Bovine oocytes collected from slaughterhouse ovaries or ovum pickup were matured for 20-22 h, then subjected to IVF using Brackett and Oliphant BO procedures with sorted X-sperm, and cultured with our standard culture system. Expanded blastocysts with tight compaction of the inner cell mass (quality 1) were selected on Day 7 for cryopreservation via liquid nitrogen surface vitrification (LNSV; Xu et al. 2006 J. Dairy Sci. 89, 2510-2518). Embryo transfer was performed for 3 replicates in Navasota, Texas, in April 2009. Prior to ET, embryos were warmed and subsequently washed several times in warming, dehydration solution and base medium. Some of sexed/vitrified embryos were cultured for 3 days post-warming to determine the survivability. The treatments were as follows: (1) vitrified-single transfers, 1 embryo was transferred into the horn ipsilateral to CL; (2) vitrified-double transfers, 1 embryo was transferred into each uterine horn by nonsurgical transfer; and (3) fresh-single, 1 fresh embryo was transferred into the horn ipsilateral to CL (control) to a synchronous recipient on Day 7. Pregnancy was determined by ultrasound monitoring on Day 35, and palpation per rectum on Day 75 after transfer. The pregnancy data were analyzed by General Linear Model analysis (SPSS 11.0, SPSS Inc., Chicago, IL, USA). The survival rate of vitrified IVF embryos reached to as high as 97.6% (n = 42) 2 h post-warming, and hatching rate was 85.7% after 3 days culture in vitro. The data (Table 1) showed that there was no difference in Day 35 pregnancy rate among vitrified-double, vitrified-single, and fresh ET control groups. However, on Day 75 post-ET, there was a significantly higher fetal loss found in the vitrified-double transfer group (41.1%) compared to those of vitrified-single transfers (16.6%) and fresh-single group (11.9%) (P < 0.05). The pregnancy rate on Day 75 of 51.4% achieved with vitrified-single transfers was comparable to the 43.3% achieved with the fresh-single control transfers but was significantly higher than the 31.1% of the vitrified-double transfer group. This study demonstrated that double embryo transfers can aggravate high fetal loss and/or abortion when sexed IVF embryos are transferred, and ET with 1 sexed/vitrified embryo per recipient is sufficient to establish satisfactory pregnancy, comparable to that achieved with fresh embryos. Table 1.Pregnancy and fetal loss of sexed/vitrified bovine IVF embryos following single and double transfers Supported by USDA/CSREES-SBIR: 2006-03069 Phase II to F. Du.

scholarly journals 174EMBRYO TRANSFER OF VITRIFIED IVF EMBRYOS IN CATTLE: PREGNANCY COMPARISON AFTER SINGLE AND DOUBLE TRANSFER

2004 ◽  
Vol 16 (2) ◽  
pp. 209 ◽  
Author(s):  
F.L. Du ◽  
A. Dinnyes ◽  
L.Y. Sung ◽  
J. Xu ◽  
S. Jiang ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Essential Amino Acids ◽  
Hatching Rate ◽  
Gestation Length ◽  
Vitro Fertilization ◽  
The Usa ◽  
Vitrification Solution

Advancement in vitrification of in vitro-produced bovine embryos will benifit the cattle breeding and production industry. The objective was to evaluate whether bilateral (double) embryo transfers (ET) can improve pregnancy rate compared to ipsilateral (single) transfers. Bovine cumulus-oocyte complexes collected from slaughterhouse ovaries were matured for 20–22h, and subsequently subjected to a standard Brackett and Oliphant in vitro fertilization (IVF). Six hours after IVF, embryos denuded of cumulus were cultured in defined CR1 medium supplemented with essential and non-essential amino acids (CR1aa), plus 6mgmL−1 BSA for 2 days at 39°C under 5% CO2, 5% O2 and 90% N2, and then cultured in CR1aa medium supplemented with 7.5% FBS for a further 5 days on bovine cumulus monolayers. Expanded blastocysts with tighter compaction of the inner cell mass (quality 1) were selected on Day 7 for cryopreservation via modified solid surface vitrification (Dinnyes et al., 2000 Biol. Reprod. 513–8). Vitrification solution contained HEPES-buffered TCM199 supplemented with 20% FBS, ethylene glycol and dimethylsulphoxide. A droplet of 1–2μL vitrification solution containing 4–5 blastocysts was dropped directly onto a cooled surface within 30s after 3-min incubation in equilibration solution. Prior to ET, embryos were warmed and subsequently washed several times in 0.25M sucrose rehydration solution and M199+7.5% FBS medium. The warmed embryos from initial trials were cultured for 2 to 72h to evaluate their viability after vitrification. During ET trails, vitrified embryos were loaded into transfer straws (one embryo per straw) after warming. The treatments were as following, (1) single transfers, one embryo was transferred into the horn ipslateral to CL; (2) double transfers, one embryo was transferred by non-surgical means into each uterine horn of a synchronous recipient on Day 7. ET trails were conducted in both the USA (double transfers) and China (single v. double transfers). Pregnancy was determined by palpation per rectum around Day 70 after transfer. The data were compared by Student’s t-test. The survival rate of vitrified IVF embryos reached as high as 91.4% (n=256) 2h post-warming, and hatching rate was 70.7% (n=154) 72h after culture in vitro, respectively. The data (Table 1) show that double transfers resulted in a significantly higher pregnancy rate than did single transfers (P&lt;0.05). With double transfers, a higher pregnancy rate was achieved in the USA than in China (76.2% v. 45.6%, P=0.079). This study confirms that double embryo transfers can improve the pregnancy outcome after ET, perhaps because bilateral placement of embryos may increase embryonic signals to the maternal environment. Further evaluation of gestation length, single/twin conception and calving difficulty is under investigation. Table 1 Pregnancy rate (Day 70) of vitrified bovine IVF embryos following single and double transfer

77 Monozygotic Twin Calves Production by Blastomere Separation Technique with Commercial Well-of-the-Well Culture Dish

2018 ◽  
Vol 30 (1) ◽  
pp. 177
Author(s):  
Y. Hashiyada ◽  
Y. Aikawa ◽  
H. Matsuda ◽  
T. Yamanouchi ◽  
Y. Goto ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Twin Pregnancy ◽  
Small Body ◽  
Fetal Loss ◽  
Monozygotic Twin ◽  
Gestation Length ◽  
Culture Dish ◽  
Significant Difference

Monozygotic twin bovine embryos can be produced by blastomere separation of 2-cell embryos and commercial well-of-the-well (WOW) culture dish (Hashiyada et al. 2016 Reprod. Fertil. Dev. 28, 178) obtaining 60% and 48% of blastocyst formation and monozygotic blastocyst pairs, respectively. The present study was conducted to evaluate the fertility of blastocysts derived from this production system in Japanese Black beef cattle. Embryos were produced using oocytes collected by ovum pick-up technique. TCM-199 supplemented with 5% calf serum (CS), Brackett-Oliphant solution supplemented with 10 mg mL−1 BSA, and CR1aa containing 5% CS, were used for each culture step: in vitro maturation, fertilization, and culture (IVM,IVF, and IVC). Two-cell stage embryos were obtained 24 to 27 h post-insemination. Zonae pellucidae were removed by exposure to 0.25% pronase. Then, embryos were separated into blastomeres by gentle pipetting in IVC medium. Each blastomere was introduced into a single conical microwell of 25 wells, each having a diameter and depth of ~287 μm and 168 μm (Dai Nippon Printing, Tokyo, Japan). Blastomeres in wells were cultured covered with a droplet of 2.5 μL of IVC medium/well. The developed blastocysts in pairs on 7 days post-insemination were used for transfer. Single embryos of monozygotic twin embryos were transferred to Japanese Black cattle with a generally small body frame to produce twin calves from a set of recipients. Twin embryos were transferred in pairs to unilateral of uterus of non-lactating Holstein cows. Pregnancy and twin pregnancy were determined at 30 days of gestation by ultrasonography and were reconfirmed at 60 days with detection of fetal loss. Statistical significance was analysed by Fisher’s exact test. There was no significant difference in pregnancy rate or twin pregnancy rate between single embryo transfer (7/14, 50% and 2/7, 28.6%) and twin embryo transfer (9/21, 42.9% and 4/21, 19%). In either transfer method, fetal loss was not observed in diagnosis carried out at 60 days by ultrasonography. To date, 2 pairs of twin calves have been obtained from twin pregnant cows by twin embryo transfer within the normal range of gestation length (286 and 288 days) and birth weight (31-40 kg). These results indicate that blastocysts developed from blastomeres separated from 2-cell embryos by culturing with commercial WOW culture dish had fertility similar to that of intact embryos derived from standard in vitro culture and further demonstrate the possibility of production of normal twin calves.

scholarly journals Effect of cysteamine supplementation during in vitro culture of early stage bovine embryos on blastocyst rate and quality

2012 ◽  
Vol 81 (3) ◽  
pp. 229-234 ◽  
Author(s):  
Martina Lojkic ◽  
Iva Getz ◽  
Marko Samardžija ◽  
Mario Matkovic ◽  
Goran Bacic ◽  
...  
Keyword(s):  
Inner Cell Mass ◽  
Culture Media ◽  
Cell Mass ◽  
Cell Number ◽  
Total Cell ◽  
Hatching Rate ◽  
Bovine Embryos ◽  
Total Cell Number ◽  
Oviductal Fluid

The aim of this study was to evaluate whether the addition of cysteamine to the in vitro culture media enhances the yield, hatching rate, total cell number and inner cell mass/total cell number ratio of bovine embryos. A total of 933 bovine oocytes collected from ovaries of 60 slaughtered donors were subjected to in vitro maturation and in vitro fertilization. Following fertilization, embryos were cultured in synthetic oviductal fluid without glucose. After 24 h embryos were transferred into synthetic oviductal fluid with 1.5 mM glucose and 0 (control), 50, 100 and 200 µM of cysteamine. After 48 h, the embryos were transferred into synthetic oviductal fluid with glucose but without cysteamine and cultured until Day 9. The number of cleaved embryos on Day 2, the total number of blastocysts on Day 7 and the number of hatched blastocysts on Day 9 were calculated. Differential staining of inner cell mass and trophectoderm cells of blastocysts were performed on Day 7 and Day 9 of in vitro culture. Supplementation of in vitro culture media with 100 µM cysteamine increased the blastocyst yield (P < 0.05) without affecting the hatching rate. Furthermore, the embryos cultured in the presence of 100 µM cysteamine had significantly higher number of inner cell mass cells (P < 0.05) and the proportion of inner cell mass cells (P < 0.05) compared with the controls. The results of the present study demonstrated that the addition of 100 µM cysteamine to the in vitro culture media improved blastocyst production rate and enhance embryo quality, which could lead to the improvement of the in vitro culture system for bovine embryos.

High hydrostatic pressure treatment improves the quality of in vitro-produced ovine blastocysts

2011 ◽  
Vol 23 (6) ◽  
pp. 809 ◽  
Author(s):  
Luisa Bogliolo ◽  
Federica Ariu ◽  
Giovanni Leoni ◽  
Stefania Uccheddu ◽  
Daniela Bebbere
Keyword(s):  
Hydrostatic Pressure ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Cell Number ◽  
Lower Percentage ◽  
Control Group ◽  
Hatching Rate ◽  
Embryo Survival

Exposure to sub-lethal hydrostatic pressure (HP) treatment is emerging as an approach to improve the general resistance of gametes and embryos to in vitro conditions. The present study was aimed to evaluate the effect of HP treatment on in vitro-produced ovine blastocysts. Experiment 1 was aimed to define optimal treatment parameters: two different HP treatments were applied to blastocysts and embryo survival was evaluated. In Experiment 2, HP parameters (40 MPa, 70 min, 38°C) selected in Experiment 1 were used to treat blastocysts. Embryo quality was assessed and compared with untreated controls by counting total cell number, the inner cell mass (ICM) and trophectoderm (TE) cells and by evaluating nuclear picnosis. HP-treated blastocysts were processed for gene expression analysis (AQP3, ATP1A1, BAX, CDH1, HSP90β, NANOG, OCT4 and TP53) 1, 5 h after the end of HP exposure. Results showed that the hatching rate of embryos treated at 40 MPa was significantly higher than that of the 60 MPa-treated group (P < 0.01) and similar to untreated embryos. Blastocysts exposed at 40 MPa showed higher ICM (P < 0.05) and TE (P < 0.01) cell number and a lower percentage of picnotic nuclei (P < 0.05) compared with the control group. Significantly lower abundance for BAX (P < 0.01) and OCT4 (P < 0.05) transcripts were observed in HP embryos than in the control group. In conclusion, treatment with HP improved the quality of in vitro-produced ovine blastocysts by increasing their cell number and reducing the proportion of nuclear picnosis.

scholarly journals Alpha-ketoglutarate affects murine embryo development through metabolic and epigenetic modulations

Reproduction ◽  
2019 ◽  
Vol 158 (2) ◽  
pp. 125-135 ◽  
Author(s):  
Zhenzhen Zhang ◽  
Changjiu He ◽  
Lu Zhang ◽  
Tianqi Zhu ◽  
Dongying Lv ◽  
...  
Keyword(s):  
Embryo Transfer ◽  
Embryo Development ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Embryonic Stem ◽  
Dna Demethylation ◽  
Basic Knowledge ◽  
Preimplantation Embryos ◽  
Foetal Growth

α-Ketoglutarate (α-KG) is an intermediary metabolite in the tricarboxylic acid (TCA) cycle and functions to inhibit ATPase and maintain the pluripotency of embryonic stem cells (ESCs); however, little is known regarding the effects of α-KG on the development of preimplantation embryos. Herein, we report that α-KG (150 μM) treatment significantly promoted the blastocyst rate, the number of inner cell mass (ICM) cells and foetal growth after embryo transfer. Mechanistic studies revealed two important pathways involved in the α-KG effects on embryo development. First, α-KG modulates mitochondria function by inducing relatively low ATP production without modification of mitochondrial copy number. The relatively low energy metabolism preserves the pluripotency and competence of the ICM. Second, α-KG modifies epigenetics in embryos cultured in vitro by affecting the activity of the DNA demethylation enzyme TET and the DNA methylation gene Dnmt3a to increase the ratio of 5hmC/5mC ratio. Elevation of the 5hmC/5mC ratio not only promotes the pluripotency of the ICM but also leads to a methylation level in an in vitro embryo close to that in an in vivo embryo. All these functions of α-KG collectively contribute to an increase in the number of ICM cells, leading to greater adaptation of cultured embryos to in vitro conditions and promoting foetal growth after embryo transfer. Our findings provide basic knowledge regarding the mechanisms by which α-KG affects embryo development and cell differentiation.

scholarly journals 144ARE BLASTOCYST RATES A RELIABLE INDICATOR OF THE QUALITY OF AN IVP SYSTEM?

2004 ◽  
Vol 16 (2) ◽  
pp. 194 ◽  
Author(s):  
B. Avery ◽  
T. Greve
Keyword(s):  
Developmental Stage ◽  
Developmental Stages ◽  
Inner Cell Mass ◽  
Relative Proportion ◽  
Cell Mass ◽  
Tween 20 ◽  
Hatching Rate ◽  
Trophoblast Cells ◽  
Cell Counts

Normally blastocyst rates are used to document the efficiency of an IVP system, because routine transfer of all embryos is not a realistic approach. Even though pregnancies are established, there will only be a weak correlation to a given IVP system because the embryos for transfer have been highly selected. The aim of this study was to analyze the in vitro development of bovine IVM/IVF oocytes after culture in SOFaa medium with or without the presence of bovine oviduct cells (BOEC) under 5% or 20% O2 in 5% CO2 and 38.5°C in order to select the optimal IVC system under the given circumstances. The study was based on six replicates and 2373 inseminated oocytes retrieved from abattoir ovaries, and the quality markers were Day 8 blastocyst rates (BL per inseminated oocytes), morphology, kinetics, and cell count. From the relative proportion of BL, XB, and H, an average developmental stage (kinetics) could be assigned. Ranking was based on BL rate, rates of A and B graded BL, and the average developmental stage. Established standard procedures were used for IVM (23h in DMEM with 5% serum and eCG/hCG), and IVF (23h in TALP with heparin), and the inseminated oocytes were randomly allocated into four IVC groups (5% O2, 5% O2/BOEC; 20% O2, and 20% O2/BOEC) to be cultured in groups of 25 in 0.1mL oil-covered droplets of SOFaa with 5% serum (Holm P et al. 1999 Theriogenology 52, 683–700). The morphology was graded as A: compact and distinct inner cell mass, regular morphology of trophoblast cells, development corresponding to the expected; B: smaller or less distinct inner cell mass, a few degenerated trophoblast cells or slight fragmentation, development corresponding to the expected; C: dispersed or no inner cell mass, degenerated trophoblast cells or much fragmentation, developmental arrest. For cell counts the zona and cytoplasm from the individual blastocysts were lysed in 0.01M HCL and 0.1% Tween 20, leaving the isolated nuclei to be fixed in 3:1 methanol:acetic acid on a slide (Viuff D et al. 2002 Biol. Reprod. 63, 1143–1148). The kinetics were assessed as hatched per total BL at Day 8 (Fisher’s exact test, P&lt;0.01). The BL rates were significantly lower in the 20% O2 group (23% v. 31%, 32%, 33% in the other groups, respectively), while the hatching rate was significantly higher in the 5% O2 group (35% v. 12%, 10%, 18%). The frequency of A-quality blastocysts was significantly higher in the 5% O2 and 20% O2/BOEC groups (46%, 41%) than in the 20% O2 and 5% O2/BOEC groups (27%, 22%). The B-quality frequency did not differ between the four groups (41%, 40% v. 48%, 45%), whereas the C-quality inversely reflected the A-quality (13%, 19% v. 25%, 33%). There were no differences in the cell counts between the same quality grades in the four systems. An A-grade expanded BL had 134±50 cells (mean±SD), a B-grade 94±45; a hatched A-grade BL had 168±48 cells, a B-grade 143±54. This study shows that regardless of differences in average developmental stages (kinetics) and morphology, similar blastocyst rates can be obtained. Using these criteria our four IVC groups would be ranked as (1) 5% O2, (2) 20% O2/BOEC, (3) 5% O2/BOEC (4) 20% O2. In conclusion, when evaluating the suitability of an IVP system, morphology and kinetics should be considered as well as blastocyst rates.

189 PREGNANCY RATES IN HEAT-STRESSED DAIRY CATTLE RECEIVING ONE OR TWO IN VITRO-PRODUCED EMBRYOS IN A TIMED EMBRYO TRANSFER PROGRAM

2006 ◽  
Vol 18 (2) ◽  
pp. 202
Author(s):  
M. Franco ◽  
J. Block ◽  
F. D. Jousan ◽  
L. A. de Castro e Paula ◽  
A. M. Brad ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Fetal Loss ◽  
Pregnancy Rates ◽  
Uterine Horn ◽  
Limiting Factor ◽  
Transfer Program ◽  
In Pregnancy

The objective was to determine whether transfer of two embryos would increase pregnancy rates in heat-stressed dairy recipients receiving an in vitro-produced embryo transferred into the uterine horn ipsilateral to the corpus luteum (CL). Such a treatment would increase the likelihood that the cow receives at least one embryo competent for sustained development. In addition, transfer of two embryos into the ipsilateral uterine horn is likely to increase the amounts of interferon-tau and other embryonic-signaling molecules in the uterus. A total of 32 virgin crossbreed heifers and 26 lactating crossbreed cows were used as timed embryo transfer recipients after being subjected to an ovulation synchronization protocol as follows: GnRH (100 �g) and insertion of previously used progesterone-containing CIDR on Day -10, prostaglandin F2� and CIDR removal on Day -3, and GnRH (100 �g) on Day 0 (day of anticipated ovulation). All recipients had a palpable CL on Day 6 and were randomly selected to receive one (n = 31 recipients) or two (n = 27) embryos on Day 7. At Day 64, the pregnancy rate tended to be higher (P = 0.07) for cows than for heifers. While not significant, heifers that received two embryos tended to have lower pregnancy rates than those that received a single embryo (20% vs. 41%); there was no difference in pregnancy rate in cows (50% for two embryos vs. 57% for one embryo). Pregnancy losses between Day 64 and Day 127 occurred in one group only cows receiving two embryos. In that group, pregnancy rate was 50% at Day 64 but 17% at Day 127. Overall, there was no difference in pregnancy rates at day 127 between cows and heifers, but recipients that received two embryos (17% for cows and 20% for heifers) had lower pregnancy rates (P < 0.03) than recipients that received one embryo (57% for cows and 41% for heifers). Only one animal, a cow, had twin fetuses at day 127. In conclusion, unilateral transfer of two embryos failed to improve pregnancy rates of dairy cattle exposed to heat stress. The fact that fetal loss occurred sooner for heifers than for cows points out the importance of uterine capacity as a limiting factor for maintenance of fetal development of two conceptuses. The suitability of timed embryo transfer was evident from the high pregnancy rates achieved with crossbreed females that received a single embryo. This work was supported by BARD Grant No. US-1551-14, USDA TSTAR Grant No. 2004-14135-14715, Grant No. 2001-12101-11318 from the USDA-IFAFS Program, and CAPES Grant No. 134202-1).

scholarly journals Totipotency of mouse zygotes extends to single blastomeres of embryos at the four-cell stage

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marino Maemura ◽  
Hiroaki Taketsuru ◽  
Yuki Nakajima ◽  
Ruiqi Shao ◽  
Ayaka Kakihara ◽  
...  
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Mouse Embryos ◽  
Primitive Endoderm ◽  
Cell Stage ◽  
Supportive Environment ◽  
Mouse Zygotes ◽  
Single Blastomeres ◽  
Multicellular Organisms

AbstractIn multicellular organisms, oocytes and sperm undergo fusion during fertilization and the resulting zygote gives rise to a new individual. The ability of zygotes to produce a fully formed individual from a single cell when placed in a supportive environment is known as totipotency. Given that totipotent cells are the source of all multicellular organisms, a better understanding of totipotency may have a wide-ranging impact on biology. The precise delineation of totipotent cells in mammals has remained elusive, however, although zygotes and single blastomeres of embryos at the two-cell stage have been thought to be the only totipotent cells in mice. We now show that a single blastomere of two- or four-cell mouse embryos can give rise to a fertile adult when placed in a uterus, even though blastomere isolation disturbs the transcriptome of derived embryos. Single blastomeres isolated from embryos at the eight-cell or morula stages and cultured in vitro manifested pronounced defects in the formation of epiblast and primitive endoderm by the inner cell mass and in the development of blastocysts, respectively. Our results thus indicate that totipotency of mouse zygotes extends to single blastomeres of embryos at the four-cell stage.

scholarly journals Should rescue ICSI be re-evaluated considering the deferred transfer of cryopreserved embryos in in-vitro fertilization cycles? A systematic review and meta-analysis

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Alessio Paffoni ◽  
Marco Reschini ◽  
Valerio Pisaturo ◽  
Cristina Guarneri ◽  
Simone Palini ◽  
...  
Keyword(s):  
In Vitro Fertilization ◽  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Implantation Rate ◽  
Clinical Pregnancy ◽  
Frozen Embryo Transfer ◽  
Fertilization Failure ◽  
Vitro Fertilization ◽  
Rescue Icsi

Abstract Background Total fertilization failure represents a particularly frustrating condition for couples undergoing in vitro fertilization. With the aim of reducing the occurrence of total fertilization failure, intracytoplasmic sperm injection (ICSI) has become the first choice over conventional in vitro fertilization (IVF) procedures although evidence of improved results is still debated and its use in couples without male factor infertility is not recommended. Among the strategies potentially useful to promote the use of conventional IVF, we herein call attention to the late rescue ICSI, which consists in performing ICSI after 18–24 h from conventional insemination on oocytes that show no signs of fertilization. This treatment has however been reported to be associated with a low success rate until recent observations that embryos derived from late rescue ICSI may be transferred after cryopreservation in a frozen-thawed cycle with improved results. The aim of the present study was to assess whether frozen embryos deriving from rescue ICSI performed about 24 h after conventional IVF may represent a valuable option for couples experiencing fertilization failure. Methods A systematic review on the efficacy of late rescue ICSI was performed consulting PUBMED and EMBASE. Results Including twenty-two original studies, we showed that clinical pregnancy rate per embryo transfer and implantation rate obtainable with fresh embryo transfers after rescue ICSI are not satisfactory being equal to 10 and 5%, respectively. The transfer of cryopreserved rescue ICSI embryos seems to offer a substantial improvement of success rates, with pregnancy rate per embryo transfer and implantation rate equal to 36 and 18%, respectively. Coupling rescue ICSI with frozen embryo transfer may ameliorate the clinical pregnancy rate for embryo transfer with an Odds Ratio = 4.7 (95% CI:2.6–8.6). Conclusion Results of the present review support the idea that r-ICSI coupled with frozen embryo transfer may overcome most of the technical and biological issues associated with fresh transfer after late r-ICSI, thus possibly representing an efficient procedure for couples experiencing fertilization failure following conventional IVF cycles. Trial registration Prospero registration ID: CRD42021239026.

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