Association of raised serum progesterone level with ovulation trigger and histology of endometrium in stimulated cycles

Abstract This was a forthcoming study of those patients, who undergo in-vitro fertilization (IVF) and freeze-all embryo, who acquiesce for the study. The number of participated patients (n=350) in this study, underwent for IVF. The blood sample was collected from patients to evaluate the level of serum progesterone in vacuum vials on the day of ovulation trigger. After 36 hrs of ovulation trigger, ovum picked up was done. Quantitative methods were used to estimate the level of serum progesterone through the electrochemiluminescence immunoassay and correlation of serum progesterone with embryo transfer (ET) outcomes. Main outcome of this current study was to evaluate the value of mean serum progesterone level i.e.0.868± 0.712 ng/ml and 0.88±0.723 ng/ml was found in case of pregnancy positive and negative respectively, at p=0.216 value. In antagonist (n=40) and agonist (n=310) cases, it was 8(20%) and 37(11.94%) PL occurrence was noted at p=0.143 respectively. An overall value of the premature lutenization (PL) occurrences was 13.63% and 15.25% observed in both positive and negative cases of pregnancy at p=0.216 respectively. This study concluded that 12.66% of PL occurrences were recorded in the case of IVF. Study results proved, there were no significant effect of PL on pregnancy outcomes.

Two successful embryo transfers of mini-donkey embryos in Brazilian Northeastern jennies using an alternative method: Case report.

Pregnancy rates after embryo transfer (ET) are disappointing in donkey species. This study aims to report two successful ET of mini-donkey embryos using Brazilian Northeastern jennies as recipients. Eighteen embryo flushes were performed 9 days post-ovulation in two non-pregnant mini-donkeys jennies (11 and 7 cycles per jenny). Eleven embryos (61%, 11/18) were collected and transferred to Brazilian Northeastern jennies 4-6 days post-ovulation by conventional (n = 6) or an alternative (n = 5) technique. The alternative method consisted of inserting a Polansky equine vaginal speculum smeared with lubricant in the vagina of the recipient jenny. The arms of the speculum were extended to allow the visualization of the cervix. Then, using an adapted crafted, elongated, toothed tissue grasping forceps, the external cervical os was held, and the cervix was gently pulled backward, aiming to straight the cervical canal. The ET gun was inserted through the vagina and cervix by visual inspection, and the embryo was released into the uterine lumen. All embryos collected were Grade 1 and classified as Expanded Blastocysts. No jennies become pregnant after conventional ET (0/6), whereas two recipient jennies (40%, 2/5) become pregnant and delivered offspring in the following year after ET using the alternative technique. In conclusion, Brazilian Northeastern jennies can be used as embryo recipients using the alternative method proposed in the present study. However, further investigations are needed to improve the knowledge and results of ET in donkey species.

Evaluating the use of piezo manipulator, laser or their combination for blastocoel cavity puncture to improve cryopreservation outcomes of large equine embryos.

The main difficulty of large equine embryo cryopreservation is the replacement of blastocoel fluid with cryoprotectant solution. The objective of this study was to improve the cryopreservation of large equine embryos with PMAP and/or LAP. Embryos were collected via the non-surgical transcervical procedure and divided into three groups based on their size (A ≤ 300 µm, 300 µm300 µm). However, more research is required to find the best method for embryos ≥700 µm.

The Possibility of Analyzing Endometrial Receptivity Using Cells from Embryo Transfer Catheters.

It is very important to investigate the expression of endometrial receptive markers in the endometrium during implantation. Therefore, we examined whether it would be possible to analyze endometrial receptivity using cells from embryo transfer catheters. A total of 81 cycles from 81 consenting patients were enrolled in this study. The tip of the embryo transfer (ET) catheter was cut and immersed in a dedicated reagent. Confirmation of cell distribution was carried out using a Papanicolaou stain and immunocytochemistry. Protein expression was carried out by immunocytochemistry. The expressions of estrogen receptor α, progesterone receptor, and homeobox A10 mRNA were analyzed using quantitative reverse transcription-polymerase chain reaction. We analyzed the relationship between the gene expression profiles associated with pregnancy from endometrial cells. Samples collected from the ET catheter showed clear staining for endometrial cells. Most of the cells were endometrial epithelial cells. Cervical cells were not observed. The protein expression was also confirmed. Three genes were analyzed that are associated with endometrial receptivity. Progesterone receptor expression was 1.4-fold (p<0.05) and homeobox A10 was 2.8-fold (p<0.01) higher in patients who became non-pregnant group, compared to the pregnant group. Estrogen receptor α expression tended to be higher in the non-pregnant group (p=0.18). Our results suggest that endometrial receptivity can be evaluated using cells obtained from the ET catheter. This method may be useful for elucidating the cause of implantation failure by comparing a receptive and non-receptive endometrium at the time of ET.

Embryo location in the uterus during embryo transfer: An in vitro simulation.

OBJECTIVE: To evaluate the location of transferred embryos under various parameters during embryo transfer in in vitro fertilization (IVF) by applying an in vitro experimental model for embryo transfer (ET). METHODS: Mock ET simulations were conducted with a laboratory model of the uterine cavity. The transfer catheter was loaded with a sequence of air and liquid volumes, including development-arrested embryos donated by patients. The transfer procedure was recorded using a digital video camera. An orthogonal design, including three independent variables (uterine orientation, distance of the catheter tip to the fundus, and injection speed) and one dependent variable (final embryo position), was applied. RESULTS: The uterine cavity was divided into six regions. The distribution of the transferred matter within the uterine cavity varied according to the uterine orientation. Medium speed-injected embryos were mostly found in the static region while fast- and slow-speed injected embryos were mostly found in the fundal region and the cervical-left region, respectively. The possibility of embryo separation from the air bubble increased from 11.1% in slow injection cases to 29.6% and 48.1% in medium and fast injection cases, respectively. CONCLUSION: The experimental model provides a new method for investigating ET procedures. Fast injection of embryos into a retroverted uterus may be more likely to result in embryo separation from the air bubble.

Non-surgical transfer of vitrified porcine embryos using a catheter designed for a proximal site of the uterus.

This study aimed to compare the efficiency of non-surgical embryo transfer (ET) using a newly developed catheter, which enables transferring embryos into a proximal site of the uterus (mostly uterine body), and surgical ET of vitrified porcine embryos. In Experiment 1, the catheter was inserted into 12 gilts, with each half of the group allocated to skilled or novice operators. The time required for insertion into the uterus did not differ between skilled and novice operators (4 min 9 s and 4 min 6 s, respectively). In Experiment 2, 12 gilts were used as recipients for non-surgical and surgical ET with vitrified embryos (n = 6, each). There was no significant difference in the rate of piglet production based on the number of transferred embryos between surgical and non-surgical ET (25.8% vs. 15.4%, p = .098). The results suggest that non-surgical ET catheter allowed for easy insertion and transfer of embryos without special training. Although the catheter is effective for deposition of embryos into the proximal site of uterus, the efficiency of piglet production is not enhanced compared with surgical ET. The ET method using this catheter, being labor-saving and less-invasive, may contribute to the improvement of ET in pigs.

Time-lapse technology for embryo culture and selection.

Culturing of human embryos in optimal conditions is crucial for a successful in vitro fertilisation (IVF) programme. In addition, the capacity to assess and rank embryos correctly for quality will allow for transfer of the potentially 'best' embryo first, thereby shortening the time to pregnancy, although not improving cumulative pregnancy and live birth rates. It will also encourage and facilitate the implementation of single embryo transfers, thereby increasing safety for mother and offspring. Time-lapse technology introduces the concept of stable culture conditions, in connection with the possibility of continuous viewing and documenting of the embryo throughout development. However, so far, even when embryo quality scoring is based on large datasets, or when using the time-lapse technology, the morphokinetic scores are still mainly based on subjective and intermittent annotations of morphology and timings. Also, the construction of powerful algorithms for widespread use is hampered by large variations in culture conditions between individual IVF laboratories. New methodology, involving machine learning, where every image from the time-lapse documentation is analysed by a computer programme, looking for patterns that link to outcome, may in the future provide a more accurate and non-biased embryo selection.

Influence of human embryo cultivation in a classic CO2 incubator with 20% oxygen versus benchtop incubator with 5% oxygen on live births: the randomized prospective trial.

SummaryOur objective was to assess the effect of benchtop incubators with low oxygen concentrations on the clinical and embryological parameters of our patients. We conducted a prospective, randomized, opened controlled trial on infertile patients in stimulated cycles. In total, 738 infertile patients were assessed for eligibility and, after final exclusions, 230 patients were allocated either to a 5% O2 group (benchtop incubator) or a 20% O2 group (classic incubator). Finally, 198 patients in the 5% O2 group and 195 in the 20% O2 group were analysed. The outcomes measured were fertilization rate, clinical pregnancy rate, and live birth rate. The primary outcome - live birth rate per all transfers - did not show any improvement in the 5% oxygen group over the 20% oxygen group (25.3% versus 22.6%, P=0.531), but the number of day 5 blastocysts was significantly higher (P=0.009). Fertilization rate did not show any beneficial effect of reduced oxygen (5%) (73.4%±22.4% versus 74.6%±24.0%, P=0.606) per all transfers but there was statistically significant difference in the day 5 SET subgroup (85.3±15.1 versus 75.1±17.5; P=0.004). Clinical pregnancy rate showed results in favour of the 5% oxygen group for all subgroups (day 3: 23.7% versus 21.1%, P=0.701; day 5 SET: 35.0% versus 30.6%. P=0.569) but showed statistical significance only in the day 5 SET subgroup (51.1% versus 29.8%; P=0.038). Culturing of embryos in benchtop incubators under low oxygen produced more blastocysts and therefore was a better alternative for embryo selection, which resulted in higher pregnancy rates. To achieve higher live birth rates, embryo quality is not the only factor.

Effect of Surgical Adhesive on the Uterus of Rabbits Following Occlusion.

Purpose/Aim of the Study: The present study investigated the effect of surgical adhesives on the uterus of rabbits and the histomorphology alterations following occlusion, to improve the clinical treatment of abnormal fallopian tube with surgical adhesives for in vitro fertilization and embryo transfer (IVF-ET). Materials and Methods: The experimental rabbits received laparotomy and occlusion of the uterus by surgical adhesive adjacent to the two fallopian tubes, while the control rabbits only received laparotomy. The body weight, hysterosalpingography, and histomorphology were measured to evaluate the uterine occlusion at 1 and 6 months after surgery. Results: There was no significant difference in the mortality rate or body weight between the experimental and control groups. In the experimental group, 38 uterine cavities were identified in 19 rabbits, of which 97.37% were occluded, with expanded uterine cavity and tissue oppression at 1 month after surgery. In total, 33 uterine cavities out of the 36 in the control group were occluded, with proliferation of new stratified epithelial cells observed at 6 months after surgery. In the control group, 20 uterine cavities of 10 rabbits were observed to be absent of occlusion at 1 month after surgery, while 18 uterine cavities in the remaining 9 rabbits were also absent of occlusion at 6 months after the surgery. Conclusion: Surgical adhesives are effective in occluding the uterus of rabbits without adverse effects, supporting their potential clinical use to treat the occlusion in abnormal fallopian tubes prior to IVF-ET.

Prospective Randomized Trial Comparing Embryo Transfers of Cases with and without Catheter Rotation during Its Withdrawal.

OBJECTIVE: To compare embryo transfer (ET) technique based on catheter rotation during its withdrawal in cases with unexplained infertility in a prospective, randomized trial (NCT03097042). METHODS: Two hundred intracytoplasmic sperm injection (ICSI) patients undergoing ET with cleaving or blastocyst-stage fresh embryos were randomized into 2 groups: cases with (n = 100), and without (n = 100) catheter rotation during its withdrawal. Groups were matched for age and some clinical parameters. A soft catheter was used to transfer a single embryo with catheter rotation during its withdrawal in the study group and without rotation in the control. The use of a stiff catheter or tenaculum was not needed in any case. Groups were compared in terms of cycle characteristics and clinical pregnancy rates. RESULTS: Pregnancy rate was significantly higher in the study group (41 vs. 26%, p = 0.04). Clinical pregnancy rate was also significantly higher in the study group (39 vs. 25%, OR 1.9 [1.1-3.5], p = 0.05). On the other hand, the ongoing pregnancy rate was similar between the 2 groups (33 vs. 23%, p = 0.2). CONCLUSION: Catheter rotation during its withdrawal may be associated with increased pregnancy and clinical pregnancy rates; however, the difference in ongoing pregnancy rates did not reach statistical significance.

A prospective study comparing two embryo-transfer soft catheters.

OBJECTIVES: To compare reproductive outcomes using two different soft catheters i.e. Set TDT® and Cook® Sydney IVF. The primary outcome was defined as a positive ß-human chorionic gonadotropin (ß-hCG) test. METHODS: Our prospective study recruited 68 patients undergoing in vitro fertilization cycles in a private fertility clinic in Porto Alegre, Brazil, between January 2014 and April 2016. They were divided into two groups according to the catheter that would be used for the embryo transfer, and the groups were matched by age. The total number of patients in each group was: 34 for the TDT and 34 for the Cook Sydney. All the patients were submitted to a ß-hCG test 12 days after the embryo transfer for pregnancy outcome evaluation. RESULTS: Ten out of 34 patients from the TDT group had a positive outcome for pregnancy, corresponding to 29.4%. The Cook Sydney group had 9 patients out of 34 with positive outcomes, corresponding to 26.5%. Comparing the efficacy of both catheters for the primary outcome, there was no significant difference (p>0.05) between the TDT and the Cook Sydney catheters. CONCLUSION: The TDT and the Cook Sydney catheters efficacies were similar for embryo transfer during assisted reproductive technology cycles.

Humid versus dry incubator: a prospective, randomized, controlled trial.

OBJECTIVE: To evaluate the efficacy of a dry versus humidified incubator on human embryo development ex vivo. DESIGN: Prospective, double-blind, randomized, controlled trial. SETTING: Private fertility centers. PATIENT(S): A total of 297 women undergoing in vitro fertilization randomized into two groups. INTERVENTION(S): From days 0 to day 5 or 6 of culture, intervention group embryos exposed to dry culture and control group embryos exposed to humidified culture. MAIN OUTCOME MEASURE(S): Subsequent ongoing pregnancy rate. RESULT(S): After transfer of embryos, there were statistically significantly lower rates of clinical and ongoing pregnancy in the dry culture arm than in the humidified culture arm (odds ratio [OR] 0.57; 95% confidence interval [CI], 0.36-0.91; versus OR 0.54; 95% CI, 0.34-0.85). On day 3 of culture, embryo quality and compaction were lower in the dry culture group (OR 0.38; 95% CI, 0.32-0.45) than in the group exposed to humidified culture (OR 0.23; 95% CI, 0.19-0.27). On day 5 of culture, embryos in dry culture had a lower rate of blastocyst formation (OR 0.39; 95% CI, 0.33-0.46), quality (OR 0.34; 95% CI, 0.29-0.40), and cryopreservation (OR 0.41; 95% CI, 0.35-0.48). CONCLUSION(S): In this study, human embryos cultivated ex vivo in a dry incubator had statistically significantly decreased implantation and clinical and ongoing pregnancy rates. Our findings indicate the need for larger multicenter, randomized, controlled trials. CLINICAL TRIAL REGISTRATION NUMBER: NCT01695096.

Comparison between an exclusive in vitro-produced embryo transfer system and artificial insemination for genetic, technical, and financial herd performance.

The objective of this study was to implement an in vitro-produced embryo transfer (IVP-ET) system in an existing stochastic dynamic dairy simulation model with multitrait genetics to evaluate the genetic, technical, and financial performance of a dairy herd implementing an exclusive IVP-ET or artificial insemination (AI) system. In the AI system, sexed semen was used on the genetically best heifers only. In the IVP-ET system, all of the animals in the herd were impregnated with female sexed embryos created through in vitro fertilization of oocytes collected from animals of superior genetics for different traits of interest. Each donor was assumed to yield on average 4.25 transferable embryos per collection. The remaining animals in the herd were used as recipients and received either a fresh embryo or a frozen embryo when fresh embryos were not available. Selection of donors was random or based on the greatest estimated breeding value (EBV) of lifetime net merit (NM$), milk yield, or daughter pregnancy rate. For both the IVP-ET and AI systems, culling of surplus heifer calves not needed to replace culled cows was based on the lowest EBV for the same traits. A herd of 1,000 milking cows was simulated 15 yr over time after the start of the IVP-ET system. The default cost to produce and transfer 1 embryo was set at $165. Prices of fresh embryos at which an exclusive IVP-ET system financially breaks even with the comparable AI system in yr 15 and for an investment period of 15 yr were also estimated. More surplus heifer calves were sold from the IVP-ET systems than from the comparable AI systems. The surplus calves from the IVP-ET systems were also genetically superior to the surplus calves from the comparable AI systems, which might be reflected in their market value as a premium price. The most profitable scenario among the 4 IVP-ET scenarios in yr 15 was the one in which NM$ was maximized in the herd. This scenario had an additional profit of $8/cow compared with a similar AI scenario that maximized NM$, provided that surplus heifer calves could be sold at a premium price based on the superiority of the EBV of NM$. For the IVP-ET system to be at least as profitable as the comparable AI system during a 15-yr investment period, the surplus calves from the IVP-ET system needed to be sold at the premium prices. The break-even price of fresh embryos was estimated to be $84 for the exclusive IVP-ET system. This resulted in the same profit as the AI system, which maximized NM$ for a 15-yr investment period and in which heifer calves were sold at a premium price.

Does the Presence of Blood in the Catheter or the Degree of Difficulty of Embryo Transfer Affect Live Birth?

The technique used for embryo transfer (ET) can affect implantation. Prior research that evaluated the effect of postprocedural blood of the transfer catheter tip have yielded mixed results, and it is unclear whether this is actually a marker of difficulty of the transfer. Our objective was to estimate the effect of blood at the time of ET and the difficulty of ET on live birth rates (LBR). This retrospective cohort study utilized generalized estimating equations (GEEs) with nesting for repeated cycles for all analyses. Univariate modeling was performed and a final multivariate (adjusted) GEE model accounted for all significant confounders. Embryo transfers were subjectively graded (easy, medium, or hard) by a physician at the time of transfer. The presence of blood at ET was associated with more difficult ETs, retained embryos, and presence of mucous in the catheter. In the univariate analysis, ET with blood was not associated with live birth, while the degree of difficulty for ET had a negative impact on LBR. In the final multivariate GEE model, which accounts for repeated cycles from a patient, the only factors associated with an increased LBR were the degree of difficulty of the ET, female age, and blastocyst transfer. After controlling for confounding variables, the presence of blood in the transfer catheter was not associated with the likelihood of pregnancy and thus was not an independent predictor of cycle outcome. This indicates that the difficulty of the transfer itself was a strong negative predictor of pregnancy.

[Effect of catheter choice during embryo transfer on the clinical outcome of in vitro fertilization-embryo transfer].

OBJECTIVE: To compare two flexible embryo catheters and determine whether clinical outcome differs in the in vitro fertilization-embryo transfer (IVF-ET) cycles. METHODS: This prospective control study was conducted by one doctor between July 2012 and November 2013. In the study, 2 064 patients undergoing fresh embryo transfer by using IVF-ET/intracytoplasmic sperm injection (ICSI)-ET in Reproductive Medical Center of Peking University Third Hospital were recruited. The subjects were divided into two groups. Cook Sydney IVF embryo transfer catheters (product model: K-JETS-7019-SIVF) were used for embryo transfer in group 1 (n=949), and Frydman-CCD catheters (product model: 131230301) were used in group 2 (n=1 115). Pregnancy outcomes were compared between these two groups. RESULTS: There was no significant difference in age, diagnosis for infertility and stimulation protocol used between the two groups. In addition, there was no difference in the number of oocytes collected and in the number and score of embryos transferred. The significantly higher implantation rate, clinical pregnancy rate, and live birth rate (34.40% vs. 26.92%, 51.21% vs. 41.52%, 42.57% vs. 33.09%, P<0.05) were observed in group 1 compared with group 2. The abortion rate was not significantly different between the two groups (11.93% vs. 15.98%, P>0.05). The proportion of difficult transfer was higher in group 1 than that in group 2 (5.27% vs. 3.41%, P<0.05). There was no difference in the clinical pregnancy rate and live birth rate between the two difficult transfer cycles. CONCLUSION: The type of embryo transfer catheter affects the clinical outcome in IVF. Good clinical outcome can be obtained by using Cook Sydney IVF catheter, which is worthy of clinical promotion.

Different effectiveness of closed embryo culture system with time-lapse imaging (EmbryoScope(TM)) in comparison to standard manual embryology in good and poor prognosis patients: a prospectively randomized pilot study.

BACKGROUND: Previously manual human embryology in many in vitro fertilization (IVF) centers is rapidly being replaced by closed embryo incubation systems with time-lapse imaging. Whether such systems perform comparably to manual embryology in different IVF patient populations has, however, never before been investigated. We, therefore, prospectively compared embryo quality following closed system culture with time-lapse photography (EmbryoScope™) and standard embryology. We performed a two-part prospectively randomized study in IVF (clinical trial # NCT92256309). Part A involved 31 infertile poor prognosis patients prospectively randomized to EmbryoScope™ and standard embryology. Part B involved embryos from 17 egg donor-recipient cycles resulting in large egg/embryo numbers, thus permitting prospectively alternative embryo assignments to EmbryoScope™ and standard embryology. We then compared pregnancy rates and embryo quality on day-3 after fertilization and embryologist time utilized per processed embryo. RESULTS: Part A revealed in poor prognosis patients no differences in day-3 embryo scores, implantation and clinical pregnancy rates between EmbryoScope™ and standard embryology. The EmbryoScope™, however, more than doubled embryology staff time (P < 0.0001). In Part B, embryos grown in the EmbyoScope™ demonstrated significantly poorer day-3 quality (depending on embryo parameter between P = 0.005 and P = 0.01). Suspicion that conical culture dishes of the EmbryoScope™ (EmbryoSlide™) may be the cause was disproven when standard culture dishes demonstrated no outcome difference in standard incubation. CONCLUSIONS: Though due to small patient numbers preliminary, this study raises concerns about the mostly uncontrolled introduction of closed incubation systems with time lapse imaging into routine clinical embryology. Appropriately designed and powered prospectively randomized studies appear urgently needed in well-defined patient populations before the uncontrolled utilization of these instruments further expands. TRIAL REGISTRATION: NCT02246309 Registered September 18, 2014.

Embryo Transfer with Controlled Injection Speed to Increase Pregnancy Rates: A Randomized Controlled Trial.

BACKGROUND/AIMS: Catheter injection speed affects depth and placement of the embryo into the uterine cavity and is shown to be highly variable in, and between, subjects in a manually performed embryo transfer. In an effort to standardize the injection speed during embryo transfer, we developed an automated transfer pump: the pump-regulated embryo transfer (PRET) device. In this randomized controlled trial, we aimed to investigate if standardization of the injection speed and pressure with this PRET results in a better controlled positioning of the transferred embryo(s). METHODS: Five hundred ninety-nine in-vitro fertilization/intracytoplasmic sperm injection/frozen-thawed embryo transfer cycles were randomly assigned to the PRET or manual transfer. Positioning of the embryo(s) into the uterine cavity was measured with ultrasound. RESULTS: The PRET device generates a significantly smaller variance of the positioning of the embryo(s) into the uterine cavity. This resulted in an ongoing pregnancy rate of 21% in the PRET versus 17% in the manual (p = 0.22) transfer group; frozen-thawed embryo transfers resulted in 17.5 versus 10.9% (p = 0.097), respectively. CONCLUSION: The PRET results in better controlled positioning of the embryo(s), and it also gives the opportunity to standardize embryo transfer. Whether the PRET may positively influence pregnancy rates, needs to be investigated in a multicenter trial.

¿Debemos de congelar todos los embriones para transferir en diferido? / Should we transfer frozen instead of fresh embryos?

Existen evidencias crecientes en la literatura que demuestran que la estimulación ovárica, la cual produce niveles suprafisiológicos de hormonas, puede disminuir la tasa de gestación frente a los ciclos de criotransferencias. Además, el desarrollo endometrial puede controlarse de forma más precisa en los ciclos con embriones congelados y descongelados. Ya que la criopreservación es un procedimiento de rutina en el laboratorio de FIV, y dado el incremento de resultados, la política de congelación de todos los embriones para transferir en diferido, es una alternativa emergente para mejorar los resultados en FIV. Con la política de congelar todos los embriones, se criopreservan todos los embriones obtenidos en un ciclo de FIV y la transferencia se realiza más tarde, o bien en un ciclo natural o sustituido. La ventaja de este método es que proporciona un mejor ambiente y más fisiológico a los embriones, y pueden obtenerse mejores tasas de gestación y menos morbilidad materna y perinatal. Sin embargo, existen controversias en la literatura sobre el uso generalizado de esta estrategia. Por eso, el objetivo de esta revisión es examinar la literatura al respecto, identificando resultados de estudios randomizados en los que se criopreservan todos los embriones y se comparan con los resultados de embriones en fresco. También se estudian los posibles inconvenientes de esta técnica

Growing evidence in the literature shows that controlled ovarian stimulation, with supraphysiologic hormonal levels, may decrease pregnancy rate against frozen-thawed cycles. Moreover, endometrial development can be controlled more precisely during its priming for frozen-thawed embryo transfer vs. for controlled ovarian stimulation. Therefore, as the embryo cryopreservation has become a routine procedure in IVF labs , the ''freeze-all'' policy has emerged as an alternative to fresh ET to improve IVF outcomes. With the freeze-all policy, the entire cohort of embryos is cryopreserved, and the ET is performed later in a natural cycle, or in a cycle with hormonal replacement for endometrial priming. The potential advantage of this method is that it provides a more physiologic environment in which ET can occur; this advantage could lead to better pregnancy rates and decrease maternal and perinatal morbidity. However, controversies remain regarding patient selection and the threshold at which a cycle becomes supraphysiologic. The purpose of the present systematic review was to examine the literature and identify results of randomized clinical trials to assess if the cryopreservation of all embryos of good quality, and subsequent transference, is associated with improvements in the ART outcomes compared with fresh embryo transfer

Predictive value of the time interval between embryo loading and transfer for IVF/ICSI success: a prospective cohort study.

BACKGROUND: The influence of embryo loading time (ELT) and the time interval between embryo loading and embryo transfer (TIEL-ET) on the success of IVF/ICSI is unknown. METHODS: In a prospective cohort study, we aimed to ascertain the influence of ELT and TIEL-ET on ongoing pregnancy rate (OPR) and life birth rate (LBR). Data from 603 consecutive embryo transfers between January 2008 and December 2013 were collected. A complete data set including the outcomes of interest OPR and LBR was available for 410 women. The primary outcome was IVF/ICSI success, defined as OPR and LBR. RESULTS: We used univariate and multivariate logistic regression for analysis. In a multivariate analysis, age (odds ratio [OR] 0.94; 95% confidence interval [CI] 0.89-0.99), catheter type (OR 0.45; 95% CI 0.24-0.84), and uterine length (OR 1.03; 95% CI 1.01-1.06), but not ELT and TIELT-ET were independently associated with OPR. Regarding LBR, age (OR 0.93; 95% CI 0.88-0.98), catheter type (OR 0.41; 95% CI 0.22-0.79), and uterine length (OR 1.03; 95% CI 1.01-1.06), but not ELT and TIELT-ET were independent predictors. CONCLUSION: We conclude that speed of embryo transfer is not critical for the success of IVF/ICSI. However, care should be taken to choose catheter types proven to be associated with a high success rate.

Prevalence, consequence, and significance of reverse cleavage by human embryos viewed with the use of the Embryoscope time-lapse video system.

OBJECTIVE: To investigate the prevalence and potential causes of reverse cleavage (RC) by human early-cleavage embryos and its associations with embryonic development and implantation after transfer. DESIGN: Clinical retrospective cohort study. SETTING: Private fertility treatment center. PATIENT(S): A total of 126 consecutive in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) treatment cycles, with 353 IVF and 436 ICSI embryos cultured in the Embryoscope until day 3. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Embryo assessment on day 3, incidence of abnormal division, embryo morphokinetic parameters, and fetal heart beat. RESULT(S): RC, referring to either blastomere fusion or failed cytokinesis, occurred up to three times per individual embryo in 27.4% of embryos during the first three cleavage cycles. A higher incidence was associated with GnRH antagonist cycles compared with agonist cycles (odds ratio [OR] 1.683), or with ICSI compared with IVF (OR 1.600). After ICSI, sperm progressive motility was associated with RC (area under the receiver operating characteristic curve: 0.573). Compared with RC-negative embryos, a lower proportion of RC-positive embryos reached 6-cell stage or beyond by day 3 (47.7% vs. 71.7%), and were more likely to have multinucleation at the 4-cell stage (10.1% vs. 5.0%). Embryos showing RC had significantly poorer performance in both conventional grading and morphokinetic parameters, and they implanted less (0/22 vs. 29/131) than those not showing RC. CONCLUSION(S): RC significantly compromised embryo development, culminating in poor implantation potential. For each embryo, it can occur on more than one occasion at any stage during the first 3 days of culture. It is associated with factors affecting both oocyte and sperm.