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Surgical method of embryo collection and embryo transfer was used in rabbit. PMSG was used for superovulation. Out of the 41 embryos collected from 6 donors, 30 embryos were transferred in 7 recipients. Out of 7 embryo transferred recipients, 2 kidded giving birth to 7 kids.
The role of embryo transfer and its associated difficulties on the outcome of human in-vitro fertilization (IVF) were examined using a standardized procedure and a scoring system (embryo transfer scores 1-5). This system was used to assess any effects of the smooth muscle relaxant glyceryl trinitrate (GTN) on embryo transfer. Patients (n = 120) were randomized in a double-blind manner at their first embryo transfer to receive sublingual GTN or placebo before the transfer. Retrospective analysis showed that higher pregnancy rates were associated with uncomplicated transfers (score 1; P < 0.01). The outcome measures included pregnancy rate, total time of cervical manipulation (embryo transfer time) and embryo transfer score. All pregnancies had a transfer score of 1 or 2, but no recorded parameter differentiated between pregnant or non-pregnant cycles, and GTN had no significant effect on any parameter.
OBJECTIVE: To evaluate viability and implantation potential of cryopreserved blastocysts according to the day of blastocyst expansion and cryopreservation. DESIGN: Retrospective study. SETTING: Private ART center. PATIENT(S): Three hundred and seventy-five patients undergoing embryo transfer with cryopreserved blastocysts. INTERVENTION(S): Blastocyst cryopreservation on day 5, 6, or 7 after oocyte retrieval according to the day of blastocyst expansion and subsequent embryo transfer. MAIN OUTCOME MEASURE(S): Clinical pregnancy rate (PR) per embryo transfer. RESULT(S): Clinical PRs were similar between blastocysts cryopreserved on day 5 and blastocysts cryopreserved on day 6 (32% vs. 28%). The clinical PR was lower for blastocysts cryopreserved on day 7 (15%), but this difference was not statistically significant after accounting for the number of embryos per transfer (P=.15). CONCLUSION(S): Viability and implantation potential are similar for day 5 and day 6 blastocyst cryopreservation. Viability may be reduced for blastocysts cryopreserved on day 7, but not to the extent suggested by reports of fresh transfers. These results suggest that reduced success rates associated with fresh transfers of later developing blastocysts may be the result of asynchrony with endometrial receptivity instead of poorer embryo quality.
Our in vitro fertilization and embryo transfer program really began in September 1980. Yet attempts to collect oocytes had been performed since 1978, and the first in vitro fertilizations were obtained in May 1979. The first pregnancy was obtained in April 1981, but it ended on the 12th week by a spontaneous abortion of a 45,X fetus. We have distinguished two periods in our program. The initial phase was from September 1980 until November 1982: ovulation monitoring of 365 cycles, spontaneous or stimulated, 276 laparoscopies, and 121 embryos transfers were performed, and 12 early pregnancies obtained (4.3% per laparoscopy and 9.9% per embryo transfer). Seven normal healthy infants were born (five boys and two girls); four cases were limited to biochemical pregnancies and one spontaneous abortion (yet described) was observed. The second and actual phase, December 1982-June 1983, is described more precisely: ovulation monitoring of 329 cycles, after stimulation protocols with clomiphene citrate and human menopausal gonadotropin, 230 laparoscopies, and 162 embryos transfers have been performed and have led to 34 pregnancies (14.8% per laparoscopy and 20.9% per embryo transfer). Eighteen of these 34 pregnancies are actually in progress (more than 12 weeks), 9 were limited to an increase in plasma human chorionic gonadotropin, and 7 cases ended in spontaneous abortions between 6 and 12 weeks.
In the present study, embryo transfer was performed using frozen-thawed embryos to establish a SPF colony of human apolipoprotein (a) (apo(a)) transgenic rabbits. Apo(a) transgenic rabbits were kept under conventional condition and were infected with Bordetella bronchiseptica. Embryos at the morula stage were collected and stored in liquid nitrogen. After thawing, the in vitro survival rate was 84.6%, and 125 morphologically normal embryos were transferred to 6 SPF recipient rabbits. Four rabbits became pregnant and 23 live pups were born. PCR and Western blot analyses revealed that 9 of 23 pups were transgenic and expressed apo(a) protein. Microbiological tests showed all rabbits were free from infections. We succeeded in establishing a SPF colony of apo(a) transgenic rabbits. These rabbits are now maintained under a barrier system and are available for medical research.
PURPOSE OF REVIEW: Embryo transfer is arguably the most critical step in assisted reproduction. The purpose of this article is to review the different aspects of the procedure in the light of recent evidence. RECENT FINDINGS: Randomized trials have shown that significantly higher pregnancy rates are obtained when embryo transfer is performed under ultrasound guidance, the embryos are deposited in the middle part of the uterine cavity, an atraumatic technique is used and when low-dose aspirin is routinely administered following the procedure. Blood in the catheter and leaving the embryos inside it for more than 120 s diminish the pregnancy rate significantly. Air in the catheter, immediate removal of the catheter, performing two transfers in the same cycle, prolonged bed rest, sexual intercourse after embryo transfer or the use of sildenafil do not affect the results. Based on currently available evidence, Cochrane reviews have concluded that the live birth rate is not increased by delaying embryo transfer from day two to three or to the blastocyst stage, and that single embryo transfer leads to lower live birth rates than the transfer of two embryos. The value of a mock transfer a few days before the actual procedure has been challenged as the position of the uterus may change. The effect of holding the cervix with a volsellum, routinely administering antibiotics and the superiority of one catheter over the others is still to be determined. SUMMARY: Recent studies confirm the importance of the various aspects of embryo transfer. More randomized studies are needed to further evaluate them.
The present study aims to ascertain whether sex selection may be inadvertently performed in human in-vitro fertilization (IVF) and embryo transfer (IVF-embryo transfer) programmes when selecting for high quality embryos (those with the fastest cleaving rates and/or the best morphology) at the fresh transfer cycle. All patients entering into the study were treated with gonadotrophins after pituitary suppression with gonadotrophin-releasing hormone agonists (GnRHa) and had intrauterine embryo transfer on day 2 post-insemination. These patients were retrospectively divided into three groups according to whether the difference in mean number of cells between embryos transferred and all embryos available for transfer in a given cycle was less than (negative selection), equal to (no selection) or greater (positive selection) than zero. In cycles resulting in singleton births, the sex ratio of the resulting babies was significantly (P < or = 0.005) shifted toward the female (88.8%) and to the male (90.0%) in the negative and positive selection groups respectively. No shift in sex ratio was observed in cycles resulting in multiple births. Maternal age was another independent factor affecting sex ratio at birth. Sex ratio was significantly (P < or = 0.05) skewed in favour of males (62.7%) and females (71.4%) in women < 35 and > or = 35 years of age respectively. Maternal age, number of embryos transferred and the event of selecting or not selecting the slowest cleaving embryos for transfer were entered automatically in a three-group discriminant model for distinguishing cycles resulting in only boys, both boys and girls, and only girls. These data suggest that (i) sex selection may be inadvertently performed in IVF-embryo transfer programmes when selecting for high quality embryos at the fresh transfer cycles; (ii) human endometria may be favourable, indifferent or hostile to either fast cleaving or slow cleaving embryos depending on maternal age; and (iii) "natural' sex selection may be performed for social, psychological or medical reasons.
BACKGROUND: Single embryo transfer (particularly of a top quality embryo) is an excellent model to correlate embryo quality in terms of morphological criteria to early pregnancy. We investigated whether this model could provide us with more information on what happens after implantation in the first trimester of pregnancy. METHODS: The outcome of 370 consecutive single top quality embryo transfers in patients younger than 38 years was analysed for pregnancy and first-trimester pregnancy loss (FTPL) before 13 weeks of gestation. Analysis was done on each cohort of embryos from which the transferred top quality embryo was selected. Serum HCG levels were measured on day 8 and day 12 after day 3 embryo transfer. The HCG index was calculated as the level of HCG on day 12/HCG on day 8. RESULTS: The pregnancy rate after single top quality embryo transfer was 51.9%. This was independent of the patients' age. FTPL, however, appeared to be age dependent: 15.4% for the whole group, 9% in patients younger than 30 years and 19% in patients above 30 years. The pregnancy rate was 50% in IVF cycles and 52% in ICSI cycles; FTPL was 19% in IVF cycles and 10% in ICSI cycles. Multiple regression analysis showed that these differences originated from age differences between both populations rather than from technique-related factors. An HCG level >or=45 IU/l on day 12 was predictive for ongoing pregnancy with 75.6% sensitivity and 100% specificity; an HCG index >or=3.5 similarly predicted ongoing pregnancy with 72.3% sensitivity and 100% specificity. CONCLUSIONS: These data show that embryo selection for transfer on day 3 can be used as an excellent tool for prediction of pregnancy but not for prediction of FTPL. The pregnancy rate of a single top quality embryo is not related to age, whereas FTPL is age dependent.
The International Embryo Transfer Society (IETS) was founded in 1974. Early members used the society as a forum for the exchange of scientific and technical information relevant to a newly emerging embryo transfer industry. The impact that embryo transfer could have on the international trade of livestock genetics was clear by 1982, so the IETS commissioned the Import/Export Committee. The initial challenge for this Committee was to deal with concerns about disease transmission via embryo transfer. Many of the early concerns have been dispelled, but at the time they threatened the continued development of a fledgling industry. Over the past two decades, many new critical challenges have been met and managed by this Committee, which was recently renamed the Health and Safety Advisory Committee (HASAC). Assessing risks of animal disease transmission via reproductive technologies and establishing protocols for managing these risks are still major issues for HASAC. However, additional concerns have developed as views of the society changed and as novel applications of biotechnology in farm animals were identified. This paper is intended to chronicle some of the major changes and challenges that were managed by members of the HASAC and its Subcommittees from the early years of embryo transfer to the current millennium with technological advances in molecular biology.
OBJECTIVE: To evaluate the clinical performance of gamete intrafallopian transfer (GIFT) and in vitro fertilization and embryo transfer (IVF-ET). METHODS: Infertile women were divided into 2 groups: for GIFT, 239 patients (326 cycles) with at least 1 patent tube; and, for IVF-ET, 125 patients (210 cycles) with bilateral tubal occlusion. A specially designed retractor was developed to replace the gametes into an appropriate section of the Fallopian tube accurately and safely. Several parameters, including the pregnancy and delivery rates of each group, were compared. RESULTS: The success rate per trial in the GIFT group was approximately 1.5 times higher than that in the IVF group (pregnancy rate: 44.2% vs. 31.0%, p < 0.01; delivery rate: 33.4% vs. 22.9%, p < 0.01). The pregnancy and delivery rates of GIFT decreased steadily with the number of trials. These apparent decreases were not observed up to the 3rd trial in IVF-ET cases. CONCLUSIONS: GIFT with a minilaparotomy procedure yielded significantly higher success rates than IVF-ET. Accordingly, GIFT is considered to be the first treatment choice in infertility cases with at least 1 patent Fallopian tube.
In spite of the efforts made in in-vitro fertilization and embryo transfer in recent years, little progress has so far been made with regard to the pregnancy rate. While embryo transfer rates of over 80% are now being attained, the pregnancy rate achieved with extracorporal fertilization in the majority of study groups is well under 20%. Between 1981 and May 1986, 1088 laparoscopies were performed in our study group with the aim of follicle puncture and subsequent in-vitro fertilization and embryo transfer. A total of 171 pregnancies resulted from 832 embryo transfers. The pregnancy rate has been increased since 1981 to 21.2% at present (1986). Since April 1986 we have been using a modified embryo transfer procedure: in 25 patients embryo transfer has been accomplished under barbiturate anesthesia. Twelve of these patients have become pregnant, i.e., 48% of the embryo transfers. There are signs that this embryo transfer method will lead to a distinct improvement in the pregnancy rate. An attempt should be made to confirm these provisional results in a larger collective.
Multiple pregnancies are considered the most frequent and serious complication of assisted reproduction technology. To reduce the frequency of multiple pregnancies, several centers have adopted a policy of reducing the number of embryos transferred in the uterus, suggesting single embryo transfer. Even though a significant number of papers have been published on this issue, no general consensus exists on how many embryos to replace in the uterus and at which cleavage stage. We conducted a retrospective study on cycles performed throughout 2003, analyzing the relation between the number of embryos transferred and the pregnancy and implantation rates, evaluating also the role of the woman's age. No differences were found among the groups except in one-embryo transferred women, which were mostly natural cycles, for estradiol levels, number of mature oocytes retrieved, number of top quality embryos, and pregnancy rate. The implantation rate was significantly higher in the two-embryo transfers versus three-embryo transfers. We found higher pregnancy and implantation rates with similar multiple pregnancy rates in patients where only two embryos were transferred versus three embryos transfer when women were less than 35 years old. In women aged less than 35 years, which in turn have the higher expectancy of successful pregnancy and also the higher risk of multiple pregnancy, the single embryo transfer is a suitable choice for these patients.
Attempts to improve clinical pregnancy rates after in-vitro fertilization (IVF) and embryo transfer are constantly being made. Two changes in technique of embryo transfer of potential clinical importance were evaluated over two contiguous time periods in order to observe any corresponding change in clinical pregnancy (CP) rate per transfer: (i) embryo transfer catheter; (ii) ultrasound guidance. Catheter choices were hard: Tefcat, Tom Cat, or Norfolk; or soft: Frydman or Wallace. Ultrasound visualization was considered to be excellent/good when the catheter could be followed from the cervix to the fundus by transabdominal ultrasound with retention of the embryo-containing fluid droplet; fair/poor if visualization could not document the sequence of events. Embryo transfers were performed in 518 cycles. CP rates per transfer using soft and hard catheters was 36 and 17% (P < 0.000) respectively. CP rates per transfer for transfers performed with and without ultrasound guidance were 38 and 25% (P < 0.002) respectively. A statistically significant difference was also noted when visualization ranks were compared. CP rates per transfer in all excellent/good ultrasound-guided transfers was 41.5 versus 16.7% for fair/poor transfers (P < 0.038). In conclusion, performance of embryo transfer with a soft catheter under ultrasound guidance with good visualization resulted in a significant increase in clinical pregnancy rates.
PURPOSE: The purpose of this study is to elucidate the fate of embryos transferred into the uterus. METHODS: Implantation rates were compared between synchronous and asynchronous intrauterine embryo transfers in mice. Then transferred embryos were recovered from the uterus and examined morphologically 24 hr after transfer. Moreover, the same transfer-recovery experiments were performed after ligation of the uterus two-thirds from the uterotubal junction immediately before transfer. RESULTS: The implantation rate was high (58.4% per embryo, 87.5% per recipient) when blastocysts were transferred into the uteri of recipients of pseudopregnant Day 4, but it was very low (0-2.4% per embryo, 0-8.3% per recipient) when blastocysts were transferred to recipients of pseudopregnant Day 2, or two-cell embryos into recipients of pseudopregnant Days 2 and 4. When transferred embryos were recovered from the uterus 24 hr after transfer, few embryos (1.4%) were recovered in asynchronous transfers, while 66.3% of the embryos were recovered in synchronous transfers. However, from recipients in which the lower portions of uteri were ligated, embryos at more advanced stages were recovered even in asynchronous transfers. CONCLUSIONS: These results suggest that discharge from the uterus is one of the major causes of the low implantation rate for asynchronous transfer.
PURPOSE: To determine the efficiency of transferring human zygotes as opposed to human day 2 or 3 embryos. METHODS: A prospective, randomized, Multicenter trial. Patients were randomized into zygote or embryo transfer. Patients were prepared for oocyte retrieval using standardized protocols. Oocyte retrieval was performed under general anesthesia. Oocytes and spermatozoa were treated using standard laboratory techniques. All protocols were coordinated by the coordinating center. RESULTS: A total of 386 patients were included in the trial. Pregnancy rates were 36.5% after zygote transfer and 42% after embryo transfer. Implantation rates were equivalent (17%) in both groups. CONCLUSIONS: No general difference was observed for zygote or embryo transfer. The results suggest that zygote transfer is a valid alternative to embryo transfer.
OBJECTIVE: To investigate whether ultrasound (US) guided embryo transfer could improve pregnancy rates. METHODS: A prospective randomized trial was conducted to compare embryo transfer under abdominal US guidance (n = 178) with traditional embryo transfer (n = 152). RESULTS: The clinical pregnancy rate was 37.1% (66/178) in the US group compared with 25.0% (38/152) in the traditional group (P < 0.05). CONCLUSIONS: US guided embryo transfer after in vitro fertilization increased pregnancy and implantation rates. It is suggested that embryo transfer should be performed under ultrasound guidance.
A report is given about one case of ectopic pregnancy after in vitro fertilization and transfer of three embryos. Possible causes of ectopic pregnancies following embryo transfer and conclusions are discussed.
A case of combined cornual pregnancy and intrauterine twin pregnancy after in vitro fertilization (IVF) and transfer of six embryos is presented. The case was diagnosed as intrauterine triplets ultrasonographically at seven weeks of gestation. Unfortunately, the patient suffered from severe lower abdominal pain and hypovolemic shock at 10 weeks of gestation, and an emergent laparotomy was done. During the operation, a ruptured cornual pregnancy with accompanying hemoperitoneum was found. Because fetal heart beats were not detected by intraoperative ultrasonography in the other two intrauterine fetuses, evacuation of the gestational contents through the uterine defect was done, and the rupture site was repaired. The incidence, mechanism and management of heterotopic pregnancies after in vitro fertilization and embryo transfer are discussed.