Embryo Transfer Technique Research Articles

Training of reproductive endocrinology and infertility fellows for embryo transfer did not result in a decrement in pregnancy

Although the majority of fellows report that adequate training in embryo transfer technique is an important component of fellowship, the question of whether skill acquisition can be attained without a reduction in pregnancy outcome remains unclear. The objective was to assess if embryo transfers performed by fellows demonstrated a pregnancy rate comparable to staff physicians.

Embryo Transfer Catheter Contamination With Intravaginal Progesterone Preparations in a Simulated Embryo Transfer Model Impairs Mouse Embryo Development: Are There Implications for Human Embryo Transfer Technique?

To study the effect of embryo transfer (ET) catheter contact with intravaginal progesterone preparations on mouse embryo development. In a simulated ET model, ET catheters were loaded with culture medium, placed in contact with intravaginal progesterone gel (Crinone 8%) or micronized progesterone intravaginal inserts (Endometrin 100 mg), and the intracatheter culture medium flushed. Embryos were cultured in the flushed culture medium at variable dilutions for variable lengths of time. Proportion of embryos progressing to blastocyst, embryo cell number, and apoptotic index was analyzed. None of the embryos cultured in undiluted progesterone-exposed medium progressed to blastocyst. The likelihood of achieving blastocyst status and the average embryo cell number increased significantly as culture media exposed to intravaginal progesterone was diluted. A significant decrease in cell number became apparent between 1 and 2 hours of exposure. Interestingly, the apoptotic index was significantly higher in progesterone-exposed embryos as compared to unexposed embryos. The contamination of ET catheter with intravaginal progesterone significantly impairs mouse embryo development, likely due in part to increased programmed cell death.

APLICACIÓN DE LA TÉCNICA NO QUIRÚRGICA DE TRANSFERENCIA DE EMBRIONES BOVINOS EN UN ESTABLO DE LA CUENCA LECHERA DE LIMA.

The study aimed to evaluate the superovulatory response and conception rate byapplying the technique of non-surgical embryo transfer in dairy cows of a commercialfarm in the Lima milkshed. Eight donor cows were used and distributed in two workingyears. Donors were synchronized with estrogens, progestagens and luteolitic agents,superovulated with 400 mg of FSH, and inseminated with two doses of frozen semen. Therecipient animals (n=28) were also distributed in two years. The Pre-synch protocol wasused for estrus synchronization in the first year and the CIDR-synch protocol in thesecond year. The expected day of heat presentation coincided for both donors andrecipients. The recovery of embryos was done seven days post service where embryoswere classified and immediately transferred. Pregnancy diagnosis by transrectalultrasonography was done at day 28 post transfer. A total of 23 embryos were obtained.The embryo recovery rate was 36.5% with high variation between years. Seventeenembryos were transferred and the conception rate was 40% with high variation betweenyears (22.2 and 66.7%). The varied individual response of the donors affected the embryorecovery rate and the synchronization protocol affected conception rate.

Gravidezes Bem Sucedidas com Recurso a Fertilização In Vitro após Oclusão de Hidrossalpinge Unilateral com Essure®

Since two decades we witnessed the publication of several studies devoted to the study of the influence of the presence of hydrosalpinx on the results of embryo transfer techniques. The aim of this study is to present the results of treatment and pregnancy outcomes in women with a history of infertility associated with unilateral hydrosalpinx, visible on vaginal ultrasound, which were subjected to unilateral occlusion with Essure® and subsequent treatment with in vitro fertilization. We performed a prospective analysis of a sample of 6 women, with a history of infertility and unilateral hydrosalpinx, between April 2010 to May 2013. In all cases we proceeded to unilateral hysteroscopic placement of the Essure® microinsert, prior to performing a cycle for in vitro fertilization. Of the 6 patients undergoing in vitro fertilization, 4 became pregnant (66.7%). Of these, two were uneventful pregnancies until delivery and 2 are still under surveillance, without complications. Of the patients who did not become pregnant after in vitro fertilization (n = 2, 33.3%), 1 conceived spontaneously during the subsequent monitoring. The advancement of hysteroscopy in the treatment of hydrosalpinx using the Essure® microinsert placement is a valid alternative to the laparoscopic approach. This study suggests the effectiveness of unilateral tubal occlusion caused by Essure® microinsert in improving outcomes of in vitro fertilization treatment in cases of infertility associated with unilateral hydrosalpinx, visible in the vaginal ultrasound.

Practice of embryo transfer: recommendations during and after.

Many patient and embryo factors influence the outcome of assisted reproductive technology (ART) treatment. The predictors for a successful ART cycle include female age, ovarian reserve, embryo quality, endometrial receptivity, and embryo transfer (ET) technique. ET, the final step of ART, has recently been noted as a crucial step affecting ART success. Variables affecting pregnancy rates following ET include ultrasound guidance, ease of ET transfer, catheter type, transfer and catheter-loading technique, blood or mucus effects, retained embryos, trial transfer, the physician's experience, and catheter tip placement. Despite the lack of consensus regarding the optimal ET technique, it is generally recommended that during ET, the disruption of the endometrium and the induction of uterine contractions should be avoided. The exposure of embryos to the ambient conditions should be minimized, and the embryo(s) should be placed at an optimal position within the fundal region of the uterine cavity.

Individualized embryo transfer training: timing and performance.

How long is the individualized training and the stability of competence for the embryo transfer (ET) technique? The embryo transfer technique is easy-to-learn, hardly unlearned, and training should be individualized by monitoring with learning curve-cumulative summation (LC-CUSUM) curves. Like many medical procedures, embryo transfer is an operator-dependent technique. Individualized or standardized training of these medical procedures should be monitored to determine when competence is acquired. This prospective, monocentric study involving five embryo transfer trainees was carried out between August 2011 and November 2012. The study was carried out in a large private clinic. Five gynaecologist trainees during their first year of assisted reproduction subspecialty performed embryo transfer for patients undergoing either fresh IVF, oocyte donor IVF, or frozen embryo transfer. There were 586 embryo transfers performed in 96 sessions of 3-10 embryo transfers each. An embryo transfer was considered successful if it gave rise to a positive pregnancy test 14 days later. LC-CUSUM and cumulative summation (CUSUM) curves were used to determine when competence was acquired and whether it was maintained over time, respectively. The length of time between two consecutive sessions was assessed for an effect on consolidation of the acquired competence. We observed that all five trainees became proficient in embryo transfer by procedure 15 (after procedure 15, 9, 7, 13 and 9, respectively). Once competence was achieved, one of the five trainees showed a loss of proficiency. After having acquired competence, the median pregnancy rate per embryo transfer session was significantly lower when the interval between consecutive embryo transfer sessions was ≥10 days compared with <10 days (20.0 versus 46.7%; P = 0.006). The patient groups included in the study were heterogeneous (IVF, oocyte donor IVF and frozen embryo transfer) and their outcomes are very variable; thus the distribution and proportion of these groups can determine the timing of competence acquisition. Our data show that low numbers of embryo transfer are needed to acquire competence, but since a relative high percentage of embryo transfers in our practice are from oocyte donor IVF, extrapolation of the findings to other clinical context should be done with caution. Personalized embryo transfer training is feasible and useful, allowing clinics, on one hand, to offer a maximum chances of pregnancy with fully trained personnel, and the other hand, to avoid the superfluous and costly overtraining of already proficient trainees. Furthermore, it is advisable to maintain a short interval of time between consecutive embryo transfer sessions after a trainee has acquired competence, to avoid a significant drop in the resulting pregnancy rate. This work was supported in part by funding from Fundació Privada EUGIN. There are no conflicts of interest to declare.

Worldwide survey of IVF practices: trigger, retrieval and embryo transfer techniques.

To identify common and varying practice patterns used by in vitro fertilization (IVF) providers from a broadly distributed, worldwide survey. Specific information regarding clinical IVF practices involving the oocyte maturation triggering, oocyte retrieval and embryo transfer was elicited. This is an internet-based questionnaire study of IVF practices throughout the world. We used 26 multiple choice questions regarding common clinical practices. The data reported are weighted based on the number of IVF cycles performed at the specific IVF center, represented by a single respondent. Surveys were completed from 359 centers in 71 countries throughout the world. The most common practice patterns (defined as ≥75% of IVF cycles) identified included: use of human chorionic gonadotropin (hCG) for trigger with an antagonist protocol, no routine patient monitoring from hCG trigger to oocyte retrieval, timing oocyte retrieval 34-37h following oocyte maturing trigger, use of a single lumen retrieval needle, no routine tests following oocyte retrieval prior to patient discharge and use of ultrasound assistance with embryo transfer. This is the largest and most diversely represented survey of specific IVF practices addressing oocyte maturation triggers, oocyte retrieval and embryo transfers. Several uniform practice patterns were identified that can be correlated with evidence-based medicine; however, we identified multiple variable practice patterns which is likely the result of the absence of definitive evidence to guide IVF practitioners. The results of this survey allow IVF providers to compare their specific practice patterns with those of a global diverse population of IVF providers.

Utero-tubal Embryo Transfer and Vasectomy in the Mouse Model

The transfer of preimplantation embryos to a surrogate female is a required step for the production of genetically modified mice or to study the effects of epigenetic alterations originated during preimplantation development on subsequent fetal development and adult health. The use of an effective and consistent embryo transfer technique is crucial to enhance the generation of genetically modified animals and to determine the effect of different treatments on implantation rates and survival to term. Embryos at the blastocyst stage are usually transferred by uterine transfer, performing a puncture in the uterine wall to introduce the embryo manipulation pipette. The orifice performed in the uterus does not close after the pipette has been withdrawn, and the embryos can outflow to the abdominal cavity due to the positive pressure of the uterus. The puncture can also produce a hemorrhage that impairs implantation, blocks the transfer pipette and may affect embryo development, especially when embryos without zona are transferred. Consequently, this technique often results in very variable and overall low embryo survival rates. Avoiding these negative effects, utero-tubal embryo transfer take advantage of the utero-tubal junction as a natural barrier that impedes embryo outflow and avoid the puncture of the uterine wall. Vasectomized males are required for obtaining pseudopregnant recipients. A technique to perform vasectomy is described as a complement to the utero-tubal embryo transfer.

Correction: Evidence in Sheep for Pre-Natal Transmission of Scrapie to Lambs from Infected Mothers

Natural scrapie transmission from infected ewes to their lambs is thought to occur by the oral route around the time of birth. However the hypothesis that scrapie transmission can also occur before birth (in utero) is not currently favoured by most researchers. As scrapie is an opportunistic infection with multiple infection routes likely to be functional in sheep, definitive evidence for or against transmission from ewe to her developing fetus has been difficult to achieve. In addition the very early literature on maternal transmission of scrapie in sheep was compromised by lack of knowledge of the role of the PRNP (prion protein) gene in control of susceptibility to scrapie. In this study we experimentally infected pregnant ewes of known PRNP genotype with a distinctive scrapie strain (SSBP/1) and looked for evidence of transmission of SSBP/1 to the offspring. The sheep were from the NPU Cheviot flock, which has endemic natural scrapie from which SSBP/1 can be differentiated on the basis of histology, genetics of disease incidence and strain typing bioassay in mice. We used embryo transfer techniques to allow sheep fetuses of scrapie-susceptible PRNP genotypes to develop in a range of scrapie-resistant and susceptible recipient mothers and challenged the recipients with SSBP/1. Scrapie clinical disease, caused by both natural scrapie and SSBP/1, occurred in the progeny but evidence (including mouse strain typing) of SSBP/1 infection was found only in lambs born to fully susceptible recipient mothers. Progeny were not protected from transmission of natural scrapie or SSBP/1 by washing of embryos to International Embryo Transfer Society standards or by caesarean derivation and complete separation from their birth mothers. Our results strongly suggest that pre-natal (in utero) transmission of scrapie may have occurred in these sheep. Citation: Foster JD, Goldmann W, Hunter N (2013) Evidence in Sheep for Pre-Natal Transmission of Scrapie to Lambs from Infected Mothers. PLoS ONE 8(11): e79433. doi:10.1371/journal.pone.0079433 Editor: Ilia V. Baskakov, University of Maryland School of Medicine, United States of America Received September 11, 2013; Accepted September 19, 2013; Published November 18, 2013 Copyright: 2013 Foster et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: The project was funded by Defra (UK Department for the Environment, Food and Rural Affairs) Grant number SE1823 (www.gov.co.uk/defra) with core support funding to the Institute for Animal Health from BBSRC (UK Biotechnology and Biological Sciences Research Council). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: nora.hunter@roslin.ed.ac.uk

Assisted reproductive techniques.

Assisted reproductive technologies (ART) encompass fertility treatments, which involve manipulations of both oocyte and sperm in vitro. This chapter provides a brief overview of ART, including indications for treatment, ovarian reserve testing, selection of controlled ovarian hyperstimulation (COH) protocols, laboratory techniques of ART including in vitro fertilization (IVF), and intracytoplasmic sperm injection (ICSI), embryo transfer techniques, and luteal phase support. This chapter also discusses potential complications of ART, namely ovarian hyperstimulation syndrome (OHSS) and multiple gestations, and the perinatal outcomes of ART.

Microdrop in utero movements after embryo transfer

Introduction: Embryo transfer (ET) techniques and modifications have been extensively studied recently as one the main variables affecting in vitro fertilization (IVF) pregnancy rates; many of ET independent variables have been studied with discordant results: A better understanding of endometrial movements could help improve ET efficiency and IVF success. Objectives: The aim of this study was to record and study microdrop in utero movements after ET by ultrasound (US). Materials and Methods: 18 patients underwent pelvic US for 4 h following ET, at 15 min intervals. ET occurred on day + 3 of embryo development following IVF stimulation. The microdrop that contained the embryos consisted of 25 ΅L of culture media and was randomly placed 1-3 cm from the fundus. Results: The microdrop could be seen leaving the catheter and deposited in the final 3 cm of the uterine cavity. In the following US, endometrial wave movements flowing from the cervix to fundus and fundus to cervix could clearly be seen, and these waves started at both ends simultaneously. The microdrop moved from the fundus to about 1 cm from the isthmus, and back again. There were times when it was virtually stationary. In all cases, after 1 h the microdrop had moved from its original position. The intensity of the endometrial movements was different in every patient. Discussion: The endometrial waves that start immediately after ET probably serve to keep the embryo within the uterine cavity, and to select the most appropriate place for implantation. This study shows for the first time microdrop movements after ET. Given this endometrial activity, we should not be concerned about positioning the embryo correctly at transfer as simply ensuring the catheter is within the uterine cavity should be enough, avoiding endometrial damage.

Test of long‐term uterine survival after allogeneic transplantation in rabbits

To see if: (i) a large vessel aortocaval vascular patch technique may bring about long-term graft survival after allogeneic uterine transplantation (UTn) in a rabbit model; and (ii) fertility can be achieved following natural mating post-allogeneic UTn. Allogeneic uterine cross transplantations were performed in New Zealand white rabbits using an aortocaval macrovascular patch harvested as part of the uterine allograft. Five rabbit recipients received a uterine graft from five unrelated donor rabbits. All female rabbits were unrelated and were of proven fertility with at least one previous litter each. Tacrolimus was administrated for immunosuppression post-transplant. Natural mating was attempted if long-term survival had been achieved. The main outcome measures were: (i) long-term recipient survival; (ii) long-term adequate uterine perfusion; and (iii) successful pregnancy post-UTn. All five recipient animals survived the surgery with satisfactory immediate postoperative recovery. Recipients 1, 2 and 4 died within the first 4 postoperative days. Both long-term survivors failed to conceive following introduction of a proven male breeder despite evidence of mating. Necropsy at 9 and 11 months showed a lack of patency of uterine cornua at the point of anastomosis, albeit a small uterus in recipient 3 and a reddish brown amorphous material at the site of the transplanted uterus in recipient 5. We have demonstrated the feasibility of uterine allotransplantation using a macrovascular patch technique, but could not demonstrate conception because of blocked cornua. To address this, we propose using embryo transfer techniques in order to achieve conception.

Evidence in sheep for pre-natal transmission of scrapie to lambs from infected mothers.

Natural scrapie transmission from infected ewes to their lambs is thought to occur by the oral route around the time of birth. However the hypothesis that scrapie transmission can also occur before birth (in utero) is not currently favoured by most researchers. As scrapie is an opportunistic infection with multiple infection routes likely to be functional in sheep, definitive evidence for or against transmission from ewe to her developing fetus has been difficult to achieve. In addition the very early literature on maternal transmission of scrapie in sheep was compromised by lack of knowledge of the role of the PRNP (prion protein) gene in control of susceptibility to scrapie. In this study we experimentally infected pregnant ewes of known PRNP genotype with a distinctive scrapie strain (SSBP/1) and looked for evidence of transmission of SSBP/1 to the offspring. The sheep were from the NPU Cheviot flock, which has endemic natural scrapie from which SSBP/1 can be differentiated on the basis of histology, genetics of disease incidence and strain typing bioassay in mice. We used embryo transfer techniques to allow sheep fetuses of scrapie-susceptible PRNP genotypes to develop in a range of scrapie-resistant and susceptible recipient mothers and challenged the recipients with SSBP/1. Scrapie clinical disease, caused by both natural scrapie and SSBP/1, occurred in the progeny but evidence (including mouse strain typing) of SSBP/1 infection was found only in lambs born to fully susceptible recipient mothers. Progeny were not protected from transmission of natural scrapie or SSBP/1 by washing of embryos to International Embryo Transfer Society standards or by caesarean derivation and complete separation from their birth mothers. Our results strongly suggest that pre-natal (in utero) transmission of scrapie may have occurred in these sheep.

The importance of the length of uterine cavity, the position of the tip of the inner catheter and the distance between the fundal endometrial surface and the air bubbles as determinants of the pregnancy rate in IVF cycles

ObjectiveTo evaluate the relationship between the pregnancy rate (PR) and the positioning of the intrauterine catheter at embryo transfer (ET) under transabdominal ultrasound (US) guidance in in vitro fertilization (IVF) cycles. Study designProspective data analysis of 281 consecutive US-guided fresh ETs performed by a single physician at Yeditepe University Hospital IVF Center, Istanbul, Turkey, after controlled ovarian hyperstimulation between April 2012 and March 2013. The length of the uterine cavity (A), the distance between the fundal endometrial surface and the tip of inner catheter (B), the distance between the fundal endometrial surface and the air bubbles (C), and the pregnancy rates (PRs) were recorded. ResultsThe mean age of the patients was 33.25±5.5 years. Of all transfers, 115 (40.9%) resulted in a clinical pregnancy. With regard to distance (C), the clinical intrauterine pregnancy rates were 65.2%, 32.2% and 2.6% in the <10mm, 10–20mm, and 20mm distance groups, respectively. The PR was dramatically reduced in cases with >10mm between the fundal endometrial surface and the air bubbles, although this did not reach statistical significance. Between those patients who conceived and those who did not, there was no significant difference in terms of the distance between the fundal endometrial surface and the tip of inner catheter, the ratio of A/B or the ratio of B/C. ConclusionsThe final position of the air bubble used as an identifier of the position of the embryo at ET can be determinative for PR, although it cannot be predicted. Clinical pregnancy rates appeared higher in cases with air bubbles closer to the fundus and the optimal position of the air bubble seems to be a distance of <10mm from the fundal endometrial surface. It could be advisable to monitor the final position of air bubble at ET for identifying PR. In addition, the depth of uterine cavity may be considered to indirectly be important factor as it affects ET depth. The optimal distance between the fundal endometrial surface and the tip of inner catheter is 1.5–2cm. Further well-designed randomized controlled trials are required to optimize ET technique in the future.

Multiple Ovulation and Non-Surgical Embryo Transfer in Cattle by Using Intravaginal Controlled Internal Drug Release (CIDR) Progesterone Inserts

This paper has been presented to share the protocol and techniques of multiple ovulation and non-surgical embryo transfer in cattle among Nepalese animal scientists. Three elite Holstein cows kept for research and study purpose in the animal farm of the University of Queensland, Gatton, Australia were selected as donors of the embryo for this multiple ovulation and embryo transfer program. Similarly, 11 Holstein heifers of age 14 to 20 months from the same farm were selected as recipients for the program. Synchronization of estrus in both donor and recipients and superovulation in donor has been done by using intravaginal controlled internal drug release (CIDR) progesterone inserts, GnRH, FSH and PGF2á as per a set protocol. Oestrus was detected by heat mount detector and artificial insemination in donors was done immediately after detecting heat and repeated every 12 hours for 2 to 3 times with semen of proven bulls. Embryos from the donors were recovered by flushing using Foley catheter. The embryos were then evaluated microscopically according to the stage of development and quality of them. The embryos were non-surgically transferred into recipients by using embryo transfer gun. Unrecovered embryos were terminated by injecting PGF2á after 6 days. The pregnancies in recipients were diagnosed on 45th day of transfer by real time ultrasonography (USG). All of the recipients (100%) came in estrus within 72 hours of removal of CIDR while it took 96 hours after removal of CIDR to donors to show the sign of estrus. Sixteen embryos were recovered from three donors out of which 11 (68.75 %) were transferable. Number of transferable embryos could be collected from one donor which could affect the average result. Five cows (62.5%) were pregnant when diagnosed by ultrasonography (USG) after 7 weeks. Nepal Journal of Science and Technology Vol. 14, No. 1 (2013) 15-22 DOI: http://dx.doi.org/10.3126/njst.v14i1.8872

Design, development, and application of a non-surgical deep uterine embryo transfer technique in pigs

There is enormous potential for the use of embryo transfer in pig production because it should make it possible to move genetic material (i.e., embryos) with minimal risk of disease transmission, reduced transportation costs, and no effect on animal welfare during transport. Unlike other livestock, the commercial use of embryo transfer in pigs has been very limited because embryo collection and transfer require surgical procedures. Recently, a new and unique procedure for the non-surgical transfer of porcine embryos deep into a uterine horn of non-sedated gilts and sows has been developed. The excellent reproductive performance of recipients following non-surgical transfer of fresh embryos and the promising results obtained with vitrified embryos represent a fundamental advance in the widespread commercial use of embryo transfer by the pig industry.

Effect of the afterloaded external guidance embryo transfer technique on pregnancy rates in single embryo transfer cycles

To investigate effect of the afterloaded external guidance embryo transfer technique on pregnancy rates in single embryo transfer intracytoplasmic sperm injection (ICSI) cycles. This retrospective study was performed at the Dr. Zekai Tahir Burak Women's Health Research and Education Hospital. Three hundred and thirteen women who underwent ICSI were included in the study. Subjects were categorized according to the embryo transfer technique; Group 1 (n: 232): easy transfer with a soft catheter, Group 2 (n: 45): after external guidance transfer, and Group 3 (n: 36): difficult transfer with a stylet. Basal parameters, clinical and laboratory IVF outcomes and pregnancy rates were studied. Infertility etiology, basal follicle stimulating hormone (FSH) levels, antral follicle count, duration of stimulation, total dose of gonadotropin, peak estradiol levels, endometrial thickness, oocyte number, 2 PN, and fertilization rate were similar between the three groups (p>0.05). Despite the decreased pregnancy rate in Group 3, there were no differences in clinical pregnancy rates among the groups (p=0.204). Embryo transfer is one of the critical steps in assisted reproduction procedures. Using the afterloaded external guidance embryo transfer technique did not improve pregnancy rates.

The importance of distances parameters at the embryo transfer techniques as a determinant on pregnancy rate in in vitro fertilization cycles

The aim of present study is to evaluate the relationship between length of uterine cavity (A), the distance between the end of the fundal endometrial surface and the tip of inner catheter (B), the distance between fundal endometrial surface and air bubbles (C) and pregnancy rates (PRs) IVF cycles after ET carried out under transabdominal ultrasonography (US) guidance.

Forced collapse of the blastocoel enhances survival of cryotop vitrified bovine hatching/hatched blastocysts derived from in vitro fertilization and somatic cell nuclear transfer

Freezing of bovine blastocysts has been widely used to improve the feasibility of cattle production by the embryo transfer technique. However, the low survival of vitrified-warmed embryos and their further development are crucial problems. Particularly, the production of offspring in vitrified-warmed bovine hatching/hatched blastocysts derived from in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT) is very low. Thus, we examined the effects of forced blastocoel collapse (FBC) before vitrification of bovine IVF- and SCNT-derived hatching/hatched embryos on the survival rate and apoptosis index after warming. Under optimal conditions, the overall survival rates in vitrified-warmed bovine IVF- and SCNT-derived hatching/hatched blastocysts were higher in FBC groups than in non-FBC groups (p<0.05). The total cell numbers of vitrified-warmed hatching/hatched blastocysts were higher in FBC groups than in non-FBC groups (p<0.05). Otherwise, the number of apoptotic positive cells of vitrified-warmed hatching/hatched blastocysts was lower in FBC groups than in non-FBC groups (p<0.05). Taken together, these findings suggest that forced collapse of the blastocoel using a pulled Pasteur pipette is an effective pretreatment technique for vitrification of bovine IVF- and SCNT-derived hatching/hatched blastocysts.

Impact of different embryo loading techniques on pregnancy rates in in vitro fertlizaton/embryo transfer cycles

BACKGROUND:Embryo transfer (ET) technique is one of the important factors of in vitro fertlization success. Among the different steps in ET technique, less attention has been given to embryo loading (EL). The aim was to compare the impact of two different techniques of EL on pregnancy rate in IVF/ET cycles.MATERIALS AND METHODS:In this retrospective study, 144 and 170 patients were placed in groups A and B, respectively. In Group A, the embryos were drawn directly into the ET catheter from culture microdrop under the oil. In Group B, the embryos were transferred from culture microdrop into G2 medium in center-well dish. Then, the embryos were drawn into the catheter and finally transferred into the uterus. Both groups were adjusted for other parameters based on the EL technique. The main outcome measure was pregnancy rate.RESULTS:There were insignificant differences for etiology of infertility, source of sperm, type of stimulation protocol, percent of IVF or intracytoplasmic sperm injection type of ET catheter, cycles with good quality embryos and transferred embryos between two groups. The rate of both chemical and clinical pregnancy was higher in Group B compared to A, but the difference was insignificant (P = 0.09 and P = 0.1, respectively).CONCLUSION:It seems that there is no difference in the outcome by loading the embryo from microdrop or center-well dish.