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PubMed1999

The current status of equine embryo transfer.

The use of embryo transfer in the horse has increased steadily over the past two decades. However, several unique biological features as well as technical problems have limited its widespread use in the horse as compared with that in the cattle industry. Factors that affect embryo recovery include the day of recovery, number of ovulations, age of the donor and the quality of sire's semen. Generally, embryo recoveries are performed 7 or 8 d after ovulation unless the embryos are to be frozen, in which case recovery is performed 6 d after ovulation. Most embryos are recovered from single-ovulating mares. Because there is no commercially available hormonal preparation for inducing multiple ovulation in the horse, equine pituitary extract has been used to increase the number of ovulations in treated mares, but FSH of ovine or porcine origin is relatively ineffective in inducing multiple ovulation in the mare. Factors shown to affect pregnancy rates after embryo transfer include method of transfer, synchrony of the donor and recipient, embryo quality, and management of the recipient. One of the major improvements in equine embryo transfer over the last several years is the ability to store embryos at 5 degrees C and thus ship them to a centralized station for transfer into recipient mares. Embryos are collected by practitioners on the farm, cooled to 5 degrees C in a passive cooling unit and shipped to an embryo transfer station without a major decrease in fertility. However, progress in developing techniques for freezing equine embryos has been slow. Currently, only small, Day-6 equine embryos can be frozen with reasonable success. Additional studies are needed to refine the techniques for freezing embryos collected from mares 7 or 8 d after ovulation. Demand for the development of assisted reproductive techniques in the horse has increased dramatically. Collection of equine oocytes by transvaginal, ultrasound-guided puncture and the transfer of these oocytes into recipients is now being used to produce pregnancies from donors that had previously been unable to provide embryos. In vitro fertilization, however, has been essentially unsuccessful in the horse. One alternative to in vitro fertilization that has shown promise is intracytoplasmic sperm injection. However, culture conditions for in vitro-produced embryos appear to be inadequate. The continued demand for assisted reproductive technology will likely result in the further development of techniques that are suitable for use in the horse.

Animals↗

PubMed2004

Cervical dilatation has a positive impact on the outcome of IVF in randomly assigned cases having two previous difficult embryo transfers.

BACKGROUND: The difficulty of embryo transfer has been reported to affect success rates in some centres, but not in others. Cervical dilatation has been proposed as a means to overcome difficult embryo transfer, but consistent criteria for patient selection are lacking. In a prospective randomized study, we examined the influence of cervical dilatation 1-3 months before embryo transfer on the outcome of IVF in cases having difficult embryo transfer in two previously failed IVF cycles. METHODS: Two alternative methods of embryo transfer preparation were evaluated in 283 randomly assigned women having difficult embryo transfers in two previously failed IVF attempts. Randomization was made using a computer-generated random number table. Cervical dilatation before starting any IVF treatment was used in 145 cases, and no dilatation was performed in 138 cases. RESULTS: The cervical dilatation group yielded a significantly higher pregnancy rate than the non-dilated group (40% versus 24%; P < 0.01). Likewise, the implantation rate (24.1% versus 14.9%; P < 0.01) and the live birth rate (34.48% versus 19.56%; P < 0.01) were significantly higher in the dilatation group than in the non-dilated group. CONCLUSIONS: In patients with prior difficult embryo transfer, cervical dilatation 1-3 months before embryo transfer lead to an improved pregnancy rate.

Adult↗

PubMed2006

Birthweight of singletons after assisted reproduction is higher after single- than after double-embryo transfer.

BACKGROUND: Single-embryo transfer (SET) has proven efficient in reducing multiple pregnancy rates after assisted reproduction technologies (ART). This study compares outcome of singletons after SET and double-embryo transfer (DET). METHODS: We studied 404 SET and 431 DET patients, who delivered a singleton child of >500 g after fresh embryo transfer in a first, second or third cycle. Preterm birth and low birthweight incidences and gestational age and birthweight were compared between both groups. Adjustments were made for maternal age, parity, cycle rank number, treatment indication, ART method, embryo characteristics and sex of the child. RESULTS: Singletons born after DET have a significantly lower birthweight than that after SET (3204.3 +/-617.5 g versus 3324.6+/-509.7 g , P<0.01). Also preterm birth (<37 weeks) [odds ratio (OR) 1.77, 95% confidence interval (CI) 1.06-2.94] and low birthweight (<2500 g) (OR 3.38, 95% CI 1.86-6.12) are significantly more common in DET singletons. CONCLUSIONS: Singleton birth after SET is advantageous compared with DET. This sheds new light on the reasons why singleton births following ART do worse than spontaneously conceived singletons in IVF programs, where double- or multiple-embryo transfer is standard.

Adult↗

PubMed2005

Three-dimensional ultrasound-guided embryo transfer: a preliminary study.

OBJECTIVE: Embryo transfer techniques have emerged as 1 of the most important variables during in vitro fertilization. Two-dimensional ultrasound guidance is an integral part of this procedure and a method to monitor catheter passage through the cervix into the endometrial cavity. Catheter placement may better be achieved with 3-dimensional monitoring to assess the relationship of the catheter tip to the uterine cavity. The purpose of this study was to compare the precision of catheter placement and position by 2- and 3-dimensional ultrasound. STUDY DESIGN: Twenty-four patients were studied. The cervix, uterus, and endometrial cavity were prescreened in 2 dimensions at the midline in the longitudinal plane of the uterus. Embryo transfers were then performed under 2-dimensional guidance. After satisfactory catheter placement and transfer of the embryos, the catheter was held in place for 60 to 120 seconds. During this interval, an automated, single sweep of the uterus and endometrial cavity was performed for net volume acquisition. All images were stored and retrospectively reviewed. Embryo transfer catheter placement with 2-dimensional ultrasound guidance was then compared with the images obtained in 3 simultaneous planes. RESULTS: Visualization of the embryo catheter tip with 2-dimensional ultrasound was achieved in all patients. These images suggested that the catheter was 2 cm from the uterine fundus and in the midline. Satisfactory 3-dimensional images for review and comparison were obtained in 21 of 24 patients. Three-dimensional ultrasound images confirmed placement and agreed with findings of 2-dimensional ultrasound images in 17 of 21 patients. In 4 patients, the catheter tip on 3-dimensional ultrasound was observed to be displaced either anteriorly or laterally from the ideal region as suggested by 2-dimensional ultrasound. In 1 case, the catheter tip on 3-dimensional ultrasound was observed to be far laterally in the region of the uterine cornua. CONCLUSION: Two-dimensional ultrasound-guided embryo transfer continues to be the standard for image-guided transfers. Data of the present study suggest that the precision of catheter tip placement and consequently embryo transfer may be improved with 3-dimensional imaging. Four of 21 patients studied had catheter tip placement in a different and less-than-ideal area when studied with 3-dimensional ultrasound. Three-dimensional imaging may provide an improvement in embryo transfer technique and have a positive impact on overall pregnancy rates.

Adult↗

PubMed1984

Embryo transfer in swine.

Embryo transfer is used to propagate genetically superior swine while minimizing disease risks. Embryos are harvested through a ventral midline incision in the anesthetized sow 4-6 days after estrus, using a glass tube or Foley catheter. Embryos are transferred to similarly prepared sows by injection directly into the uterus through a tomcat catheter or glass pipette. Embryos typically are transferred within a few hours of collection but may be stored in culture medium at 37 C for up to 30 hours.

Animals↗

PubMed1990

Enhancement of mononuclear cell oxidative burst by early post-transfer sera from human patients after unsuccessful embryo transfer.

Early pregnancy sera were earlier shown to modulate T lymphocyte rosetting with sheep erythrocytes. We set out to investigate whether early pregnancy sera also modulate the state of activation of another immunologically relevant cell type, the monocyte. As an index of monocyte activation, we measured phorbol ester-triggered oxidative burst activity by a highly sensitive chemiluminescence method. Contrary to our expectations, incubation of mononuclear cells with sera taken early after embryo transfer from patients with a successfully developing pregnancy had no effect. Unexpectedly, such sera from patients from a control group of patients in whom no pregnancy developed after embryo transfer caused enhancement of mononuclear cell chemiluminescence. Stimulatory activity of these sera appeared between days 4 and 6 and was maximal between days 7 and 9 post embryo transfer. Whether this phenomenon is causally related to, or represents a consequence of the failure of embryo transfer, can currently not be decided.

Chaperonin 10↗

PubMed2001

Training of providers in embryo transfer: what is the minimum number of transfers required for proficiency?

BACKGROUND: Embryo transfer represents one of the most critical procedures in the practice of assisted reproduction. The objective of this study was to identify retrospectively the minimum number of embryo transfers required to train providers properly in this skill. METHODS AND RESULTS: The study group consisted of 204 patients who received embryo transfers between January 1996 and March 2000 in a university-based programme of assisted reproduction. The main outcome measure was clinical pregnancies per embryo transfer. Five Fellow trainees performed a total of 204 embryo transfers for an overall pregnancy rate of 45.5% per embryo transfer (93/204). In comparison, the programme pregnancy rate per transfer for experienced providers was 47.3% (560/1179). A chronological graph of each individual trainee's experience for the first 50 embryo transfers performed suggested a lower initial pregnancy rate for three of the five trainees. To determine whether a learning curve might exist, results of the first 25 transfers were compared as a subgroup with the second 25 transfers. Pregnancy rates were lower for the 1-25 transfer subgroup than in the 26-50 subgroup for three of the five Fellow trainees, although the difference was not statistically significant. CONCLUSION: Clinical pregnancy rates of Fellows-in-training were indistinguishable statistically from those of experienced staff by 50 transfers.

Adult↗

PubMed2001

Successful Day 5 embryo transfer and pregnancies resulting after transport of embryos by air for biopsy and genetic analysis.

PURPOSE: Case studies of four in vitro fertilization (IVF) cycles where embryo transport by commercial airline followed by biopsy and genetic analysis with subsequent culture to Day 5 and resulting ongoing pregnancy. METHOD: Retrospective clinical case study of 4 patients requiring preimplantation genetic diagnosis (PGD) testing. Normally fertilized embryos were transported in a battery-powered portable incubator by commercial airline following evaluation for fertilization under controlled conditions from the Center for Assisted Reproduction, Bedford, Texas to the Reproductive Genetic Institute, Chicago, Illinois. Following Day 3 embryo biopsy and genetic analysis, embryos were transported back to the Center for Assisted Reproduction for Day 5 embryo transfer. RESULTS: Ongoing clinical pregnancy resulted for all patients receiving embryo transfer. CONCLUSION: These results demonstrate the feasibility of embryo transport by air for centers that do not have the in-house capabilities to perform genetic analysis. With successful pregnancies obtained through extended culture to Day 5, embryos requiring genetic analysis can be successfully transported by air, tested, and returned to the initial facility for embryo transfer without time restriction.

Adult↗

PubMed2003

Cycle characteristics of day 3 embryo transfers with 4-cell embryos only.

PURPOSE: Patient and cycle characteristics of day 3 transfers with developmentally lagging 4-cell embryos only were analyzed and related to the outcome of a live birth. METHODS: Day 3 transfers with either 4-cell embryos only (study group; n = 138) or 8-cell embryos only (control group; n = 282) were compared retrospectively. RESULTS: The total dose of FSH per treatment was higher, while the number of oocytes, zygotes, and transferred embryos was lower in the study group cycles compared to controls. The implantation, pregnancy, and live birth rates were dramatically lower in the study group compared to the control group. In the study group, the few cycles resulting in a live birth were characterized by a normal ovarian response to stimulation, similar to that of control group cycles with- or without a live birth. CONCLUSIONS: In cycles characterized by intensive ovarian stimulation, but poor response, the chance for a live birth is extremely low after day 3 transfer of 4-cell embryos.

Adult↗

PubMed2005

Randomized single versus double embryo transfer: obstetric and paediatric outcome and a cost-effectiveness analysis.

BACKGROUND: Transfer of several embryos after IVF results in a high multiple birth rate associated with increased morbidity and high costs for the neonatal care. In a previous randomized trial we demonstrated that a single embryo transfer (SET) strategy, including one fresh single embryo transfer and, if no live birth, one additional frozen-thawed SET, resulted in a live-birth rate that was not substantially lower than after double embryo transfer (DET) but markedly reduced the multiple birth rate. METHODS: We compared costs for maternal health care and productivity losses and paediatric costs for the SET and DET strategies. In addition, maternal and paediatric outcomes between the two groups were compared. RESULTS: The SET strategy resulted in lower average total costs from treatment until 6 months after delivery. There were a few more deliveries with at least one live-born child in the DET group. The incremental cost per extra delivery in the DET alternative was high, 71 940. The rates of prematurely born and low birthweight children were significantly lower with the SET strategy. There were also markedly fewer maternal and paediatric complications in the SET group. CONCLUSIONS: The SET strategy is superior to the DET strategy, when number of deliveries with at least one live-born child, incremental cost-effectiveness ratio and maternal and paediatric complications are taken into consideration. The findings do not support continuing transfers of two embryos in this group of patients.

Adult↗

PubMed2006

A randomized controlled trial of prophylactic antibiotics (co-amoxiclav) prior to embryo transfer.

BACKGROUND: Bacterial contamination of the transfer catheter during embryo transfer is associated with poor clinical outcomes. Antibiotics at the time of embryo transfer may improve outcomes. We evaluated the effect of co-amoxiclav on the rates of bacterial contamination of transfer catheters and clinical pregnancy. METHODS: On the day of oocyte collection, 350 patients were randomized, with sequentially numbered opaque-sealed envelopes containing treatment allocation assigned randomly by computer, to receive co-amoxiclav on the day before and the day of embryo transfer, or no antibiotics. Following transfer, the catheter tips were cultured and assessed to identify the organism(s) isolated and to quantify the level of the contamination. Couples were followed for 8 weeks to determine whether they had achieved clinical pregnancy. Outcome assessors were blinded to the treatment allocation, and the analysis was by intention to treat. RESULTS: Antibiotics significantly reduced catheter contamination rates (49.4 versus 62.3%, RR = 0.79, 95% CI: 0.64, 0.97, P = 0.03). There was no difference detected in clinical pregnancy rates between the two groups (36.0 versus 35.5%, P = 0.83) although there was a significant (P = 0.03) association between the level of bacterial contamination and clinical pregnancy rates. CONCLUSIONS: Co-amoxiclav reduces catheter contamination, but this is not translated into better clinically relevant outcomes such as clinical pregnancy rates. Our findings do not support the routine use of antibiotics at embryo transfer.

Adult↗

PubMed2006

Economic evaluations of single- versus double-embryo transfer in IVF.

Multiple pregnancies lead to complications and induce high costs. The most successful way to decrease multiple pregnancies in IVF is to transfer only one embryo, which might reduce the efficacy of treatment. The objective of this review is to determine which embryo-transfer policy is most cost-effective: elective single-embryo transfer (eSET) or double-embryo transfer (DET). Several databases were searched for (cost* or econ*) and (single embryo* or double embryo* or one embryo* or two embryo* or elect* embryo or multip* embryo*). On the basis of five exclusion criteria, titles and abstracts were screened by two individual reviewers. The remaining papers were read for further selection, and data were extracted from the selected studies. A total of 496 titles were identified through the searches and resulted in the selection of one observational study and three randomized studies. Study characteristics, total costs and probability of live births were extracted. Besides this, cost-effectiveness and incremental cost-effectiveness were derived. It can be concluded that DET is the most expensive strategy. DET is also most effective if performed in one fresh cycle. eSET is only preferred from a cost-effectiveness point of view when performed in good prognosis patients and when frozen/thawed cycles are included. If frozen/thawed cycles are excluded, the choice between eSET and DET depends on how much society is willing to pay for one extra successful pregnancy.

Embryo Transfer↗

PubMed2006

Transmission of mouse minute virus (MMV) but not mouse hepatitis virus (MHV) following embryo transfer with experimentally exposed in vivo-derived embryos.

The present study investigated the presence and location of fluorescent microspheres having the size of mouse hepatitis virus (MHV) and of mouse minute virus (MMV) in the zona pellucida (ZP) of in vivo-produced murine embryos, the transmission of these viruses by embryos during embryo transfer, and the time of seroconversion of recipients and pups. To this end, fertilized oocytes and morulae were exposed to different concentrations of MMVp for 16 h, while 2-cell embryos and blastocysts were coincubated for 1 h. In addition, morulae were exposed to MHV-A59 for 16 h. One group of embryos was washed, and the remaining embryos remained unwashed before embryo transfer. Serological analyses were performed by means of ELISA to detect antibodies to MHV or MMV in recipients and in progeny on Days 14, 21, 28, 42, and 63 and on Days 42, 63, 84, 112, 133, and 154, respectively, after embryo transfer. Coincubation with a minimum of 10(5)/ml of fluorescent microspheres showed that particles with a diameter of 20 nm but not 100 nm crossed the ZP of murine blastocysts. Washing generally led to a 10-fold to 100-fold reduction of MMVp. Washed MMV-exposed but not MHV-exposed embryos led to the production of antibodies independent of embryonic stage and time of virus exposure. Recipients receiving embryos exposed to a minimum of 10(7) mean tissue culture infective dose (TCID(50))/ml of MHV-A59 and 10(2) TCID(50)/ml of MMVp seroconverted by Day 42 after embryo transfer. The results indicate that MMV but not MHV can be transmitted to recipients even after washing embryos 10 times before embryo transfer.

Animals↗

PubMed1994

Embryo transfer in fallow deer (Dama dama): superovulation, embryo recovery and laparoscopic transfer of fresh and cryopreserved embryos.

Multiple ovulation-embryo transfer (MOET) protocols for farmed fallow deer (Dama dama) were investigated in a series of 3 experiments. A total of 37 donors, of either European (D.d. dama ; n = 30) or Mesopotamian hybrid (D.d. mesopotamica x D.d. dama ; n =7) genotype, each received an intravaginal silastic device containing 0.3 g progesterone (CIDR-type G device) for 14 d and injections of 0.5 units ovine FSH (8 x 0.06 unit injections from Days 10 to 14 of device insertion) and 100 IU PMSG (either with the first or last FSH injection). All donors received laparoscopic intrauterine inseminations of fresh semen (50 x 10(6) spermatozoa) from a Mesopotamian sire 36 h after withdrawal of CIDR devices. Embryos were recovered by laparotomy on Day 6 (Day 0 = estrus). Mean ovulation rates for the 3 experiments were 8.1, 9.8 and 7.0, with no effect of PMSG timing (P>0.10). However, embryo recovery rates, albeit low throughout the study (29.6%), were significantly improved with later PMSG administration (33.9 vs 20.1%; P<0.05). Hybrid and European donors performed in a similar manner. A range of embryo development stages was recovered throughout the study. In 2 experiments laparoscopic transfer of embryos to 48 recipient does treated previously with intravaginal CIDR devices for 14 d yielded a total pregnancy rate of 37.5%. In the experiment with fresh embryos, the use of clenbuterol to reduce uterine turgidity resulted in a higher proportion of does conceiving (3/4 ; 75%) compared with that of the untreated does (0/6 , 0%; P<0.05). In the second experiment, in which all the does routinely received clenbuterol, 10/19 (53%) and 5 19 (26%) does conceived following the transfer of fresh and cryopreserved embryos, respectively (P<0.05). While the overall efficiency of the MOET program was low (equivalent of 0.9 to 1.0 surrogate pregnancies per donor), improvements in the recovery rate of transferable embryos have considerable potential for genetic improvement of farm stock and captive propagation of endangered Mesopotamian fallow deer through maternal surrogacy programs.

Journal Article↗

PubMed1989

Practical experience with commercial embryo transfer in pigs.

Embryo transfer was used to introduce new genetic material into 5 commercial specific-pathogen-free pig herds in south eastern Queensland in order to reduce the risk of disease transmission. The embryos were collected surgically from gilts and sows and transferred surgically to synchronised recipient sows on the farms within 12 h. A total of 751 embryos were collected from 37 donors of which 665 were transferred to 39 recipients. Thirty-one (79.5%) farrowed with an average litter size of 8.1 +/- 3.0. The methods used to synchronise oestrus and superovulate the donors, together with a detailed description of the surgical technique are presented and discussed in relation to practical problems and limitations of the use of embryo transfer in swine.

Animal Husbandry↗

PubMed2006

The relative myth of elective single embryo transfer.

The option of single embryo transfer (SET) has recently dominated the pages of this and other medical journals. Opinions, in regards to the utility of such an approach, appear to differ between Europe and the US. While US guidelines promote a more individualized approach, European opinions, at times, even advocate mandated practice patterns. The European approach, however, fails to recognize the rather significant differences in supportive arguments between the historical switch from multiple embryo transfers to 2-embryo transfers and the current discussion, favouring a switch from 2-embryo transfer to elective (e)-SET. In the former, a significant risk of (at times, high-order) multiple pregnancies was reduced without loss of pregnancy potential. In the latter, a comparably relatively low twinning risk is reduced at the expense of declining pregnancy rates, a need for more treatment cycles, a potential delay in treatment success and, potentially, higher treatment costs. These consequences of e-SET, together with the preference of some infertility patients to actually conceive twins, raise serious questions about the wide utilization of e-SET, as has been propagated by many authorities. According to US guidelines, e-SET, therefore, appears to represent an appropriate transfer option for only a small minority of IVF patients. Argument in favour of indiscriminate SET appears unrealistic and should be reconsidered.

Cost-Benefit Analysis↗

PubMed1999

Successful non-surgical management of a heterotopic abdominal pregnancy following embryo transfer with cryopreserved-thawed embryos.

Heterotopic pregnancy is an increasingly common complication of assisted reproductive technology. Abdominal pregnancy is a rare and life-threatening form of ectopic pregnancy that can present as the extrauterine portion of a heterotopic pregnancy. We present the case of a cryopreserved-thawed embryo transfer that resulted in a simultaneous intrauterine and abdominal pregnancy first recognized at 10 weeks gestation. Ultrasound-guided transvaginal injection of potassium chloride into the abdominal pregnancy resulted in asystole and spontaneous resorption of the ectopic fetus, while the intrauterine pregnancy continued and resulted in a liveborn vaginal delivery at full term. Selective embryo reduction using a non-surgical approach in a haemodynamically stable patient can therefore be considered in the management of heterotopic abdominal pregnancy if diagnosed relatively early.

Adult↗

PubMed1990

Morphologic changes in the rat uterus following natural mating and embryo transfer.

In order to gain some insight into the putative immune suppression that may be induced at the placental implantation sites, the morphological changes at these sites following natural matings and following the transfer of embryos fertilized in vivo were studied. The only histologic parameter that showed a significant difference was the number of granulated metrial gland (GMG) cells. More GMG cells were present in allogeneic than in syngeneic pregnancies, and more GMG cells were present following embryo transfer into an allogeneic female than following the comparable natural mating. The role of the GMG cells in pregnancy is, however, still unresolved.

Animals↗