High serum oestradiol concentrations in fresh IVF cycles do not impair implantation and pregnancy rates in subsequent frozen-thawed embryo transfer cycles

High oestradiol concentrations may be detrimental to the success of in-vitro fertilization (IVF) treatment. A total of 1122 women aged <40 years who were undergoing their first IVF cycle were evaluated retrospectively. Serum oestradiol concentrations on the day of human chorionic gonadotrophin (HCG) administration were categorized into three groups: group A <10 000 pmol/l; group B 10 000-20 000 pmol/l and group C >20 000 pmol/l. In fresh cycles, group A had significantly lower pregnancy rates per transfer (16.2 versus 23.7% respectively, P = 0.005, chi(2)) and implantation rates (8.7 versus 11.7% respectively, P = 0.037, chi(2)), when compared with group B. The pregnancy rate per transfer in group C was significantly lower than that in group B (12.1 versus 23.7%, P = 0.049, chi(2)) and group C had the lowest implantation rate (6.4%). In frozen-thawed embryo transfer cycles, implantation rates in groups A, B and C were similar (7.5, 8.1 and 9.6% respectively) and the pregnancy rates were also comparable in all groups. In conclusion, high serum oestradiol concentrations in fresh IVF cycles may adversely affect implantation and pregnancy rates. Embryo quality seemed unaffected as excess embryos from different groups had similar implantation and pregnancy rates in frozen-thawed embryo transfer cycles. The reduced implantation was probably due to an adverse endometrial environment resulting from high serum oestradiol concentrations.     

Influence of position and length of uterus on implantation and clinical pregnancy rates in IVF and embryo transfer treatment cycles

In a prospective study of 807 consecutive women shown to have an apparently normal uterus after hysterosalpingography, hysteroscopy or pelvic ultrasonography prior to IVF or intracytoplasmic sperm injection (ICSI) and embryo transfer, the position and length of the uterine cavity was measured routinely at a pre-treatment mock transfer procedure. The apparent length of the uterine cavity was <7 cm in 128 women (group 1), 7-9 cm in 594 women (group 2) and >9 cm in 85 women (group 3). The uterus was noted to be retroverted in 38. 2% (308) women. The embryo transfer catheter was advanced to 5 mm from the uterine fundus based on the previously determined cavity length in all the embryo transfer procedures at 48 h after oocyte collection. Implantation and clinical pregnancy rates were not significantly different with respect to position of the uterus, difficulties encountered in passage of the catheter, mean age of the women, aetiology or duration of infertility or embryology events. An apparently greater cavity length was seen in older and/or parous women, but the difference was not statistically significant. Although the highest implantation and clinical pregnancy rates were seen in women with a cavity length of 7-9 cm (group 2) the differences were not statistically significant: group 1, 18.9 and 36. 7%; group 2, 21.0 and 46.5%; and group 3, 17.3 and 32.9% respectively. The incidence of ectopic pregnancy per reported clinical pregnancy was highest in group 1 women, being 14.9% (7/47) in comparison with group 2 (1.8%, 5/276) and group 3 (0%, 0/27) (P: < 0.0005), suggesting that the size of the uterus is a critical factor in the aetiology of ectopic pregnancy in IVF/ICSI-embryo transfer.     

The use of intra-endometrial embryo transfer for increasing the pregnancy rate

It has been demonstrated previously that pregnancy can be achievedby the direct insertion of embryos into the endometrial stroma(intra-endometrial embryo transfer) of mice. In this study weevaluated whether intra-endometrial transfer resulted in a higherpregnancy rate than conventional embryo transfer. Mouse blastocysts(ICR strain), recovered on day 4 of pregnancy, were transferredinto pseudopregnant day 2, day 3 and day 4 mice of the samestrain; 1-, 2- and 8-cell embryos were also transferred intopseudopregnant day 4 mice. In intra-endometrial embryo transfer,a 27 gauge injection needle was inserted near the utero-tubaljunction into the endometrial stroma and then removed; one blastocystwas transferred into each uterine horn with a glass micropipette.Conventional transfers were performed simultaneously as controls.The pregnancy rates and embryonic viability rates were evaluated9 days after embryo transfer. Furthermore, the rates of livebirth for intra-endometrial and conventional embryo transferswere compared when blastocysts were transferred into pseudopregnantday 4 uteri by both methods. In the transfer to pseudopregnantday 2 recipients, the pregnancy and embryonic viability rateswere significantly higher (P < 0.01) in intra-endometrial[23.4 (11/47) versus 15.9% (15/94)] than in conventional embryotransfer [4.3 (2/46) versus 2.2% (2/92)]. In the transfer topseudopregnant day 3 recipients, both rates were also higher(P < 0.01) in intra-endometrial [90.9 (40/44) versus 87.5%(77/88)] than in conventional transfer [67.4 (31/46) versus64.1% (59/ 92)]. In synchronous transfer to pseudopregnant day4 recipients, there was no difference between methods in thepregnancy rate [conventional, 48.9% (24/49); intraendometrial,50.9% (29/57)] and the embryonic viability rate [conventional,44.9% (44/98); intra-endometrial, 43.0% (49/114)]. In the transferof 1-, 2- and 8-cell embryos into pseudopregnant day 4 mice,pregnancy and embryonic viability rates were very low in bothtransfer methods. Intra-endometrial transfer produced normalliving offspring at a similar rate to conventional transfer.These results reveal that intra-endometrial transfer increasespregnancy and embryonic viability rates in asynchronous embryotransfer in mice, especially when the duration of pseudopregnancyin the recipients was less than the age of the transferred embryos.     

Birth of rhesus monkey infant after transfer of embryos derived from in-vitro matured oocytes: short communication

Although strategies for in-vitro maturation of oocytes from rodents and domestic species have been relatively successful, application of these techniques to primates has not met with similar success. Currently, evaluation of the developmental capacity of oocytes following fertilization is the only reliable means to assess cytoplasmic maturation. Although rhesus monkey blastocysts have previously been produced from in-vitro matured oocytes, full developmental competence has not been demonstrated by term development. Here we report the birth of the first non-human primate infant derived from in-vitro matured oocytes.     

A comparative approach to somatic cell nuclear transfer in the rhesus monkey

BACKGROUND: Despite the potential utility of primate somatic cell nuclear transfer (SCNT) to biomedical research and to the production of autologous embryonic stem (ES) cells for cell- or tissue-based therapy, a reliable method for SCNT is not yet available. Employing the rhesus monkey as a clinically relevant animal model, we have compared a conventional electrofusion method for SCNT with a one-step micromanipulation (OSM) method. METHODS: A prospective, randomized trial was conducted using only oocytes that were mature [metaphase II (MII)] at collection and a fibroblast-like cell line as nuclear donor cells (fetal fibroblasts). The embryos produced were characterized for in vitro developmental potential, cell number, karyotype and expression of nuclear mitotic apparatus (NuMA) and OCT-4. RESULTS: An in vitro blastocyst development rate of 24.4% was achieved with the OSM method, significantly higher than the 12.2% obtained following electrofusion. SCNT-produced embryos expressed normal karyotypes, cell numbers and NuMA and OCT-4 proteins in most cases. SCNT with male nuclear donor cells resulted in the production of male, SCNT blastocysts, eliminating the possibility of a parthenogenetic origin. Of the four fibroblast cell lines tested as nuclear donor cells, two supported the routine production of blastocysts following SCNT. CONCLUSIONS: The application of a modified SCNT technique (OSM) followed by embryo culture in hamster embryo culture medium-10 (HECM-10) allows, for the first time, the routine production of SCNT blastocysts, most of which appear normal by immunochemical, cytochemical and in vitro developmental criteria. These embryos will provide a resource for isolating ES cells and for studies of nuclear reprogramming by monkey cytoplasts.     

Elective transfer of one embryo results in an acceptable pregnancy rate and eliminates the risk of multiple birth.

To avoid multiple pregnancies without compromising pregnancy rates (PR) is a challenge in assisted reproduction. We have compared pregnancy results among 74 elective one-embryo transfers (group 2) and 94 transfers where only one embryo was available (group 1). All the fresh embryo cycles during 1997 in two clinics in Helsinki were analysed, and cumulative PR among these couples after frozen-thawed embryo transfers up to June 1998 were counted. In group 2, where at least two embryos were available for transfer, and only one was transferred on day 2 or 3, the PR per embryo transfer was 29.7%. In group 1, the PR per embryo transfer was 20.2%. In group 2, the cumulative PR after frozen-thawed embryo transfers was 47.3% per oocyte retrieval. Over the same time, 742 two-embryo transfers were carried out. The PR per embryo transfer was 29.4% in these subjects, but 23.9% of these pregnancies were twins. The implantation rates, as well as the PR, were highest when the embryos were at the four- to five-cell stage on day 2 (35.8 versus 9.7% compared with the two- to three-cell stage, P < 0.001) or at the six- to eight-cell stage on day 3 (45.5%). The PR per embryo transfer was higher when a grade 1 or 2 embryo was transferred compared with a grade three embryo (34. 0 and 26.7% versus 8.8% respectively, P < 0.05). In women 35 years or younger, the PR per elective one-embryo transfer was 32.8%. The corresponding figure in women older than 35 years was 18.8%. On the basis of these results, elective one-embryo transfer can be highly recommended, at least in subjects who are younger than 35 years of age, and who have grade one or grade two embryos available for transfer.     

Ultrasound-guided embryo transfer does not offer any benefit in clinical outcome: a randomized controlled trial

BACKGROUND: Ultrasound-guided embryo transfer (ET) is widely suggested as a standard clinical practice that improves overall embryo implantation and pregnancy rates. Various studies of this issue suffer from methodological pitfalls, so that a randomized controlled trial, which overcomes these problems, might be valuable. METHODS: Three hundred women aged <40, who underwent fresh ET, were included in this randomized, double-blind controlled trial. The K-J-SPPE echo tip soft catheter was used for the ultrasound-guided ET and the traditional K-Soft catheter for ETs not using ultrasound. One experienced operator performed all ETs. The primary study outcome was overall pregnancy rate (defined as the number of positive hCG results per transfer). RESULTS: No significant differences between groups were found regarding baseline patient and embryological characteristics, except for male factor and unexplained infertility (higher in the blind and ultrasound-guided ET group, respectively, P < 0.05). Overall pregnancy rates were 53.3 and 51.3% in the ultrasound-guided and blind ET group, respectively. Two ectopic pregnancies were reported in each group. Difficulty in cervical negotiation did not differ between the two groups. CONCLUSIONS: In patients undergoing ET by an experienced operator, ultrasound guidance did not provide any benefit in terms of overall clinical pregnancy and embryo implantation rates.     

Transvaginal ultrasound-guided embryo transfer improves pregnancy and implantation rates after IVF.

BACKGROUND: Attempts are constantly being made to improve clinical pregnancy rates after IVF and embryo transfer. Since November 1998, we have gradually been adopting transvaginal ultrasound guidance during embryo transfer. We retrospectively examined the efficacy of this method on pregnancy and implantation rates. METHODS: The results of 846 cycles from our IVF-embryo transfer programme were analysed and comparisons were made between those carried out using ultrasound guidance and those by the clinical touch method. RESULTS: Higher pregnancy and implantation rates (28.9 and 15.2% respectively) were found in the group using the transvaginal ultrasound guidance during embryo transfer compared with those in the group using the clinical touch method (13.1 and 7.0% respectively). The differences were statistically significant (P < 0.01). There was no significant difference in ectopic pregnancy rates between the two groups. CONCLUSION: The use of transvaginal ultrasound-guided embryo transfer significantly improved both pregnancy and implantation rates. Although technically difficult, we suggest its use may maximize the chances of achieving a successful pregnancy outcome.     

Implantation: Uterine fluid human decidua-associated protein 200 and implantation after embryo transfer

Uterine fluid samples from 109 patients undergoing in-vitrofertilization and embryo transfer were obtained so as to examinethe relationship between the uterine fluid concentration ofhuman decidua-associated protein (hDP) 200 and the implantationrate. The sampling was performed on the day of embryo transferwith a Wallace catheter, used for the testing of cervical patencybefore embryo replacement. The implantation rate, as well asthe pregnancy rate, demonstrated a significantly positive correlationwith the concentration of hDP 200 in the uterine fluid, measuredjust before embryo transfer. These results indicate that hDP200, identified as a rheumatoid factor secreted by the endometrium,may be involved in the implantation process.     

Single embryo transfer is an option in frozen embryo transfer

BACKGROUND: A good strategy to decrease multiple pregnancy rate in assisted reproduction technology (ART) is the use of single embryo transfer (SET). METHODS: This retrospective study analysed 1647 frozen embryo transfers carried out during 1998-2003 in Helsinki University Central Hospital; of these, 872 were double embryo transfers (DETs) and 775 SETs. The SET group included 140 (18.1%) elective SETs (eSETs). RESULTS: The yearly rate of SETs in frozen cycles increased from 28 to 66%. Overall, the clinical pregnancy rate per frozen embryo transfer was 30.7% and the delivery rate 22.6%. The delivery rate was significantly higher in DET cryocycles than in SET cryocycles (25.7 versus 19.2%, respectively; P < 0.01). In DET cryocycles, the multiple delivery rate was 21.9%, 10 times higher than that observed in cryocycles with SET (2.0%) (P < 0.0001). When eSET was applied, no difference in delivery rate was observed when compared with cryocycles with DET (28.6 and 25.7%, respectively). CONCLUSIONS: SET can be used in frozen cycles to reduce multiple delivery rates.     

Effects of in vitro oocyte maturation and embryo culture on the expression of glucose transporters, glucose metabolism and insulin signaling genes in rhesus monkey oocytes and preimplantation embryos

Glucose plays a fundamental role during oogenesis and embryogenesis, satisfying the metabolic demands of oocytes and embryos, providing for stored energy reserves in the form of glycogen and supporting nucleotide biosynthesis via the pentose phosphate pathway. Glucose also contributes to the production of amino acids, glycosylated proteins and extracellular components. A detailed understanding of the molecular mechanisms that mediate and regulate glucose uptake and metabolism at different stages of oogenesis and preimplantation embryogenesis could greatly benefit the development of improved methods for in vitro oocyte maturation and in vitro embryo production. Although these processes have been examined in a variety of rodent and agricultural species, detailed information has not yet been described for non-human primates. In this study, we examined the expression of the genes encoding glucose transporters, glucose metabolism enzymes and potential regulators of glucose metabolism in rhesus monkey oocytes and embryos. The data reveal stage-specific regulation of expression of specific types of glucose transporters, stage-specific changes in expression of genes related to different pathways of glucose metabolism and temporal changes in the expression of mRNAs related to insulin signaling. Additionally, the data reveal significant differences in expression of some of these genes in cultured embryos as compared with flushed embryos and between oocytes and embryos obtained following different hormonal stimulation and oocyte maturation protocols.     

Fresh embryo transfer is more effective than frozen for donor oocyte recipients but not for donors.

BACKGROUND: Recipients of donor oocytes need to be synchronized to the donor's cycle if fresh embryos are to be transferred on the cycle of oocyte retrieval. It would be much easier to merely retrieve the oocytes from the donor, fertilize the oocytes with the recipient's male partner's spermatozoa, cryopreserve the embryos, then transfer on an oestrogen/progesterone treatment programme. METHODS: The IVF outcomes of all patients enrolled in a shared oocyte programme from January 1997 to June 1999 were reviewed. Pregnancy and implantation rates were computed and statistically analysed. RESULTS: There was a significantly higher clinical pregnancy rate for recipients who had a fresh embryo transfer compared with recipients whose first embryo transfer consisted of frozen/thawed embryos (63.4 versus 43.6%). CONCLUSIONS: Conception is more likely after fresh than frozen embryo transfer with recipients but is similar to donor conception rates. If a uterine defect, per se, even without the use of the controlled ovarian stimulation regimen, could explain the difference between fresh pregnancy and implantation rates in donors versus recipients, then these same differences would have been seen when comparing frozen transfers, but they were, in fact, similar.     

Ultrasound-guided embryo transfer and the accuracy of trial embryo transfer

BACKGROUND: Studies have suggested that ultrasound-guided embryo transfer (UG-ET) may improve the outcome in IVF; however, several factors may account for the improvement in pregnancy rate. This study examines the use of ultrasound to determine the accuracy of trial transfer (TT) in preparation for ET. METHODS: Sixty-seven consecutive patients prospectively underwent UG-ET over a 2 month period. Total cavity length by US was compared with the length noted by TT. A difference of > or = 1 cm was considered significant. All embryos were placed within 1-2 cm of the fundus by US. RESULTS: Twenty patients (29.9%) had a difference of > or = 1 cm and 13 patients (19.4%) had a difference of < or = 1.5 cm. Patients with a difference of > or = 1 or > or = 1.5 cm had a significantly greater depth at transfer (P < 0.001) and uterine cavity length (P < 0.001) when compared with patients without a difference. Clinical pregnancy, implantation, delivery and overall miscarriage rates did not differ between patients with a difference of > or = 1 or > or = 1.5 cm versus no difference. There were no ectopic pregnancies. CONCLUSIONS: Nineteen percent of patients had a discrepancy of > or = 1.5 cm and approximately 30% had a difference of > or = 1 cm from TT at UG-ET, suggesting a benefit to UG-ET. A large prospective randomized trial comparing UG-ET with blind transfer is required to assess further if UG-ET should be used in all cases of ET.     

A prospective, randomized study comparing day 2 and day 3 embryo transfer in human IVF

It is believed that delayed transfer of embryos after IVF allows for a better selection of good quality embryos. Hence, the number of embryos and all other prognostic factors being equal, transfer of day 3 embryos should be associated with higher implantation and pregnancy rates than transfer of day 2 embryos. To investigate this hypothesis, a prospective randomized study was carried out to compare implantation and pregnancy rates between day 2 and day 3 transfers. The relationship between the embryo quality score of day 2 and day 3 embryos and their respective implantation rates was also analysed. In a 2 year period all patients undergoing infertility treatment and in whom at least seven normally fertilized oocytes were obtained were included in the study. A minimization procedure was performed taking into account the patient's age and the method of fertilization (IVF or intracytoplasmic sperm injection). By using a uniform policy of embryo transfer, the number of embryos transferred was similar in both groups. The outcome parameters were embryo quality, implantation and pregnancy rates. No difference was observed in implantation and pregnancy rates between transfers on day 2 versus day 3 (23.8 versus 23.8% and 47.9 versus 46.8% respectively). The incidence of embryos of moderate to poor quality was higher in embryos cultured for 3 days compared with those cultured for 2 days. It is concluded that the outcomes of embryo transfer in terms of implantation and pregnancy rates are comparable for day 2 and day 3 embryos, although the overall embryo quality score decreases when embryos are kept in culture till day 3.     

Influence of early ICSI-derived embryo sHLA-G expression on pregnancy and implantation rates: a prospective study

BACKGROUND: We have previously reported the retrospective observation that when at least one embryo, transferred on day 3, expressed sHLA-G above the geometric mean (sHLA-G+) 46 h post-ICSI, there was a marked improvement in both pregnancy (PR) and implantation (IR) rates. METHODS: The media surrounding individual embryos derived from ICSI performed on oocytes from 482 women < or =43 years of age were tested for sHLA-G expression by specific ELISA. RESULTS: We report here prospective results showing improved IVF results following the transfer of 'good quality' embryos (7-9 cells with <20% fragmentation) by preferentially including at least one sHLA-G+ embryos. PR and IR for women < or =38 years were 63% and 32% when one transferred embryo was sHLA-G+, and 69% and 36% when at least two embryos were sHLA-G+. When none of the embryos transferred was sHLA-G+, PR and IR were 25% and 13%, respectively. Comparable PR and IR for women 39-43 years were 29% and 11% when none of the transferred embryos were sHLA-G+; 38% and 15% when at least one sHLA-G+ embryo was transferred; and 61% and 26% when at least two 2 sHLA-G+ embryos were transferred. The data were stratified by patient age. CONCLUSIONS: PR and IR increased with the addition of each sHLA-G+ embryo, regardless of age. While there are significant barriers to routine embryo sHLA-G testing, we believe that if implemented, this would provide a mechanism for optimizing IVF PR while minimizing the risk of multiple pregnancies.     

The impact of the embryo transfer catheter on the pregnancy rate in IVF

BACKGROUND: The aim was to assess whether the type of embryo transfer set used for embryo transfer affects the ongoing pregnancy rate in IVF. METHODS: The TDT set was compared with the K-soft 5000 in a large, prospective, randomized study. Patients were randomized moments before transfer by drawing a consecutively numbered, sealed, opaque envelope indicating the catheter to be used. RESULTS: 2059 embryo transfers in 1296 patients were analysed. The ongoing pregnancy rate was significantly higher in the K-soft group. If the first transfer of a patient (n = 1296) within this study period was analysed, the ongoing pregnancy rates were 27.1 versus 20.5% (P = 0.006). If the analysis is limited to patients that underwent their very first transfer ever (n = 607), the ongoing pregnancy rates were 30.3 versus 20.0% (P = 0.003) in favour of the K-soft. CONCLUSION: We conclude from these data that the type of embryo transfer set used for embryo transfer does affect the ongoing pregnancy rate and that the impact of the variable transfer catheter on the ongoing pregnancy rate increases when the a priori chance of pregnancy increases.     

The presence of blood in the transfer catheter negatively influences outcome at embryo transfer

BACKGROUND: Embryo transfer (ET) influences pregnancy rates in patients undergoing assisted reproduction. Data are conflicting as to which variables affect ET success. This study examines variables that may affect outcome after ET in assisted reproductive technology patients who had high-quality embryos transferred. METHODS: Over a 23 month period, 669 consecutive cycles were examined. Only patients having grade I and grade II embryos, or blastocyst transfers, were included in this retrospective analysis. A total of 584 consecutive cycles met study criteria. At the time of ET, the following variables were recorded: aborted first attempt at ET; presence of blood and/or mucus in or on the transfer catheter after ET; ease of ET as judged by provider; need for mock embryo transfer immediately before the actual transfer and retention of embryos in the transfer catheter. These variables were retrospectively analysed for their impact on implantation rate (IR) and clinical pregnancy rate (CPR). RESULTS: There were 290 gestations (49.7% CPR). Multiple attempts at ET, subjective difficulty of ET, performance of a sham pass immediately prior to embryo transfer, and presence of mucus on or in the catheter did not affect the CPR or IR. No difference was noted in the mean age of patients having or lacking any of these factors. There was a significant association between the presence of blood on or in the catheter and decreased IR (P = 0.015) and CPR (P = 0.004). Retained embryos also decreased IR (P = 0.03). Multivariable analysis confirmed that the presence of blood on the transfer catheter was the most important of these transfer characteristics in predicting IR (P = 0.042) and CPR (P = 0.018). CONCLUSIONS: These results suggest that when only high-grade embryos or blastocysts are transferred, the presence of blood on the catheter is associated with decreased IR and CPR in assisted reproduction.     

Multiple pregnancy after in-vitro fertilization and embryo transfer: report of a quadruplet pregnancy and delivery

The first baby from in-vitro fertilization (IVF) was born in England in 1978 as a result of retrieval of a single preovulatory oocyte in the course of a natural cycle (Steptoe and Edwards, 1978). At present most programmes of IVF throughout the world do not use natural cycles producing only one oocyte, but rather multiple oocyte cycles produced by clomiphene citrate (CC), human menopausal gonadotrophin (HMG), or pure follicle stimulating hormone (FSH), either separately or in combination, sequentially or concomitantly, for the induction of multiple follicular maturation.     

Developmental competence of oocytes after ICSI in the rhesus monkey

Oocyte quantity and quality are critical to assisted reproductive technology (ART), yet few assessments beyond counting metaphase II (MII) oocytes exist. In this study, 30 +/- 2 oocytes per cycle were recovered from rhesus monkeys subjected to follicular stimulation with human gonadotrophins, of which 15 +/- 1 were MII. Oocyte quality was investigated by monitoring the developmental potential of oocytes subjected to intracytoplasmic sperm injection (ICSI). Despite uniform fertilization rates (71 +/- 4%), progression of embryos to blastocysts varied when expressed as a monthly average, from 20 to 85%, with lows from February to April and again in October, which could be attributed to developmental failure of a significant number of oocyte cohorts (14 of 55). Blastocyst rates, after elimination of failed cohorts, were uniform over time (59 +/- 4%). Neither culture conditions, the number of follicular stimulations, nor the individual sperm or oocyte donor were associated specifically with developmental failure, suggesting that intrinsic differences between stimulation cycles account for the observed variation in developmental potential. The in-vivo developmental competence of ICSI-produced embryos grown to blastocysts in vitro was also assessed. Two ongoing pregnancies and the birth of a normal female, 'Blastulina', represent landmarks in efforts to expand the use of ART in the rhesus monkey.