Cryopreserved-thawed Embryo Transfer Research Articles

ASSESSMENT OF PREGNANCY OUTCOMES IN DONOR OOCYTE THAW CYCLES COMPARING FRESH EMBRYO TRANSFER TO CRYOPRESERVED-THAWED EMBRYO TRANSFER: A SIBLING OOCYTE STUDY

Studies evaluating donor oocyte cycles report that embryo transfers using freshly retrieved oocytes result in a higher live birth rate compared to cryopreserved-thawed oocytes.1 However, due to logistical and financial barriers, many donor oocyte recipients continue to utilize cryopreserved oocytes. Following oocyte thaw and fertilization, resulting embryos can either be transferred at that time (fresh) or the embryo cohort can be cryopreserved followed later by a thaw and embryo transfer (cryopreserved-thawed). The objective of this study was to assess the ongoing pregnancy rates among donor oocyte thaw cycles with a fresh embryo transfer compared to a cryopreserved-thawed embryo transfer.

Optimal Duration of Progesterone Treatment before Cryopreserved-Thawed Embryo Transfer

Objective: To investigate the optimal duration of progesterone therapy before cryopreserved-thawed embryo transfer and its impact on clinical pregnancy and live birth rates. Methods: Five hundreds women undergoing cryopreserved-thawed embryo transfer were included in the study. These patients had a total of 500 embryos frozen on day 3 (n = 200), day 4 (n = 100), day 5 (n = 150) and day 6 (n = 50). Artificial endometrial preparation was successfully performed in all participants. If the endometrial thickness reached a minimum of 8 mm or in the presence of a triple-line view, the patients were divided into four different groups and each group into two subgroups according to the estimated duration of progesterone treatment to be used. Group 1 (n = 200): This group consisted of patients with day 3 embryo transfer. While 100 of 200 patients received embryo transfer after 3 days of progesterone treatment, the remaining 100 patients received embryo transfer after 4 days of progesterone treatment. Group 2 (n = 100): This group consisted of patients who underwent day 4 embryo transfer. While 50 of 100 patients had embryo transfer after 4 days of progesterone treatment, the remaining 50 patients received embryo transfer after 5 days of progesterone treatment. Group 3 (n = 150): This group consisted of patients who received day 5 embryo transfer. While 75 of 150 patients received embryo transfer after 5 days of progesterone treatment, the remaining 75 patients received embryo transfer after 6 days of progesterone treatment. Group 4 (n = 50): While 25 of 50 patients received embryo transfer after 6 days of progesterone treatment, the remaining 25 patients received embryo transfer after 7 days of progesterone treatment. The primary outcome measure of our study was to evaluate clinical pregnancy rate (CPR), ongoing pregnancy rate (OPR), live birth rate (LBR) and miscarriage rate per pregnancy. Results: Clinical pregnancy rates were found in 50 of 100 (50%) cases who were given progesterone for 3 days. Of the 100 cases who were given progesterone for 4 days, 40 clinical pregnancy was detected (40%). Both OPR and LBR were found to be significantly lower in patients who received 4 days of progesterone treatment compared to those given 3 days. The rates of miscarraige (9.09%) in patients who received progesterone treatment for 4 days were significantly higher than those who received progesterone for 3 days (5.8%). In Group 2 both OPR and LBR were found to be significantly lower in patients who received 5 days of progesterone treatment compared to those given 4 days. The rate of miscarraige (25.0%) was significantly higher in patients who received progesterone treatment for 5 days compared to those who received progesterone for 4 days (33.3%). When 75 patients in group III who underwent embryo transfer on the fifth day and received progesterone treatment for 5 days and 75 patients who were given progesterone treatment for 6 days were evaluated in terms of CPR, OPR and LBR the difference was statistically significant between the two gruops. When patients in group IV were evaluated in terms of CPR, OPR and LBR the difference was statistically insignificant. Conclusions: Extending the progestereone usage period one day before embryo transfer has been found beneficial in patients who have been transferred for only fifth day.

Association of Fresh Embryo Transfers Compared With Cryopreserved-Thawed Embryo Transfers With Live Birth Rate Among Women Undergoing Assisted Reproduction Using Freshly Retrieved Donor Oocytes

In in vitro fertilization cycles using autologous oocytes, data have demonstrated higher live birth rates following cryopreserved-thawed embryo transfers compared with fresh embryo transfers. It remains unknown if this association exists in cycles using freshly retrieved donor oocytes. To test the hypothesis that in freshly retrieved donor oocyte cycles, a fresh embryo transfer is more likely to result in a live birth compared with a cryopreserved-thawed embryo transfer. Retrospective cohort study using national data collected from the Society for Assisted Reproductive Technology for 33 863 recipients undergoing fresh donor oocyte cycles in the US between January 1, 2014 and December 31, 2017. Fresh embryo transfer and cryopreserved-thawed embryo transfer. The primary outcome was live birth rate; secondary outcomes were clinical pregnancy rate and miscarriage rate. Analyses were adjusted for donor age, day of embryo transfer, use of a gestational carrier, and assisted hatching. Recipients of fresh and cryopreserved-thawed embryos had comparable median age (42.0 [interquartile range {IQR}, 37.0-44.0] years vs 42.0 [IQR, 36.0-45.0] years), gravidity (1 [IQR, 0-2] vs 1 [IQR, 0-3]), parity (0 [IQR, 0-1] vs 1 [IQR, 0-1]), and body mass index (24.5 [IQR, 21.9-28.7] vs 24.4 [IQR, 21.6-28.7]). Of a total of 33 863 recipients who underwent 51 942 fresh donor oocyte cycles, there were 15 308 (29.5%) fresh embryo transfer cycles and 36 634 (70.5%) cryopreserved-thawed embryo transfer cycles. Blastocysts were transferred in 92.4% of fresh embryo transfer cycles and 96.5% of cryopreserved-thawed embryo transfer cycles, with no significant difference in the mean number of embryos transferred. Live birth rate following fresh embryo transfer vs cryopreserved-thawed embryo transfer was 56.6% vs 44.0% (absolute difference, 12.6% [95% CI, 11.7%-13.5%]; adjusted relative risk [aRR], 1.42 [95% CI, 1.39-1.46]). Clinical pregnancy rates were 66.7% vs 54.2%, respectively (absolute difference, 12.5% [95% CI, 11.6%-13.4%]; aRR, 1.34; [95% CI, 1.31-1.37]). Miscarriage rates were 9.3% vs 9.4%, respectively (absolute difference, 0.2% [95% CI, -0.4% to 0.7%]); aRR, 0.98 [95% CI, 0.91-1.07]). In this retrospective cohort study of women undergoing assisted reproduction using freshly retrieved donor oocytes, the use of fresh embryo transfers compared with cryopreserved-thawed embryo transfers was associated with a higher live birth rate. However, interpretation of the findings is limited by the potential for selection and confounding bias.

FRESH EMBRYO TRANSFER IMPROVES LIVE BIRTH RATE OVER FROZEN EMBRYO TRANSFER IN FRESHLY RETRIEVED DONOR EGG CYCLES

To test the hypothesis that in cycles using embryos derived from freshly retrieved donor eggs, a fresh embryo transfer (fresh ET) is more likely to result in a clinical pregnancy and live birth compared to a cryopreserved-thawed embryo transfer (CET). Retrospective cohort study using national data from the Society for Assisted Reproductive Technology (SART). Donor egg cycles in the SART database from 2014-2017 were collected. Only cycles using freshly retrieved eggs from anonymous donors were included. Cycles in which eggs were previously frozen, a known donor was used, or recipient age at time of transfer was over 55 years were excluded. All included cycles had at least one embryo available to transfer at either the cleavage or blastocyst stage. Using log binomial regression, relative risks and 95% confidence intervals were calculated for clinical pregnancy rate (CPR), live birth rate (LBR) and miscarriage rate. Crude and adjusted analyses were performed, controlling for donor age. Of a total of 51,942 donor egg cycles, 15,308 (29.5%) were fresh ET cycles and 36,634 (70.5%) were CET cycles. Both groups were similar in terms of age, gravidity, parity, BMI, infertility diagnosis, and race/ethnicity. A majority of recipients had blastocyst(s) transferred (92.4% of fresh ETs and 96.5% of CETS), with a similar mean number of embryos transferred: 1.52 ± 0.52 in the fresh and 1.39 ± 0.53 in the CET groups. Both CPR and LBR were lower after CET compared to fresh ET (CPR 54.2% vs 66.7%, aRR 0.78 [95% CI 0.76-0.79]; LBR 44.0% vs 56.6%, aRR 0.74 [95% CI 0.72-0.75]), controlled for donor age. Miscarriage rate was similar for both (9.4% following CET vs 9.3% following fresh ET, aRR 1.02 [95% CI 0.96-1.10]). CPR and LBR following transfer of fresh non-PGT-A embryos were statistically significantly higher than following transfer of PGT-A embryos (either fresh or frozen) with no difference in miscarriage rates (Table).Tabled 1Fresh non-PGT-AN = 15044Fresh and frozen PGT-AN = 2327Frozen PGT-AN = 2063RR (95% CI)aRR (95% CI)*RR (95% CI) ‡aRR (95% CI) * ‡Clinical pregnancy10026 (66.6%)1420 (61.0%)1237 (60.0%)0.92 (0.88-0.95)0.89 (0.85-0.94)0.90 (0.87-0.93)0.84 (0.79-0.90)Live birth8505 (56.5%)1191 (51.2%)1031 (50.0%)0.91 (0.87-0.94)0.89 (0.83-0.95)0.88 (0.84-0.93)0.82 (0.75-0.89)Miscarriage1396 (9.3%)203 (8.7%)183 (8.9%)0.94 (0.82-1.08)0.94 (0.76-1.17)0.96 (0.83-1.11)1.01 (0.80-1.29)* adjusted for donor age. ‡ relative risk for only frozen PGT-A compared to fresh non-PGT-A Open table in a new tab * adjusted for donor age. ‡ relative risk for only frozen PGT-A compared to fresh non-PGT-A Both CPR and LBR following the use of fresh donor eggs are over 10% higher after a fresh rather than frozen embryo transfer. This study suggests that recipients should be encouraged to undergo fresh donor egg embryo transfer without PGT-A.

The effect of laser-assisted hatching on pregnancy outcomes of cryopreserved-thawed embryo transfer: a meta-analysis of randomized controlled trials.

It is well known that laser-assisted hatching (LAH) is the most popular and ideal embryo hatching technology, but the relevance to pregnancy outcomes of cryopreserved-thawed embryo transfer (ET) is controversial. The purpose of this meta-analysis was to evaluate the effects of LAH on pregnancy outcomes of cryopreserved-thawed ET. We searched for relevant studies published in the PubMed, EMBASE, and Cochrane Central databases up to March 2017. This meta-analysis was primarily used to evaluate the effect of laser-assisted hatching on assisted reproductive outcomes: clinical pregnancy, embryo implantation, multiple pregnancy, miscarriage, and live birth. Using the Mantel-Haenszel fixed effects model and random effects model, we determined the summary odds ratios (OR) with 95% confidence intervals (CIs). There were 12 randomized controlled trials (more than 2574 participants) included in our analysis. The rates of clinical pregnancy (OR=1.65, 95% CI=1.24-2.19, I 2=49), implantation (OR=1.59, 95% CI=1.06-2.38, I 2=82%), multiple pregnancy (OR=2.30, 95% CI=1.30-4.07, I 2=33%), miscarriage (OR=0.86, 95% CI=0.50-1.48, I 2=0%), and live birth (OR=1.09, 95% CI=0.77-1.54, I 2=0%) revealed comparable results for both groups. In summary, this meta-analysis demonstrates that LAH is related to a higher clinical pregnancy rate, embryo implantation rate, and multiple pregnancy rate in women with cryopreserved-thawed embryos. However, LAH is unlikely to increase live birth rates and miscarriage rates. Due to the small sample evaluated in the pool of included studies, large-scale, prospective, randomized, controlled trials are required to determine if these small effects are clinically relevant.

Is human chorionic gonadotropin supplementation beneficial for frozen and thawed embryo transfer in estrogen/progesterone replacement cycles?: A randomized clinical trial.

AimHuman chorionic gonadotropin (hCG) is used frequently for luteal support in fresh in vitro fertilization cycles as it induces progesterone secretion from the ovaries after oocyte retrieval and modulates the endometrium for implantation in fresh cycles. In contrast, hCG is not usually used for the transfer of cryopreserved‐thawed embryos in estrogen/progesterone replacement cycles because ovulation is suppressed. However, several studies have shown that luteinizing hormone and hCG receptors are present in the human endometrium and that hCG can directly induce the decidualization of endometrial stromal cells in vitro. Thus, this study evaluated whether hCG supplementation can be beneficial for cryopreserved‐thawed embryo transfer in estrogen/progesterone replacement cycles.MethodsOne‐hundred‐and seventy‐three cryopreserved‐thawed embryo transfer cycles with estrogen/progesterone replacement were divided randomly into two groups. Transdermal oestradiol was used in combination with vaginal progesterone suppositories for HR. The embryo transfer was performed on day 17 and/or day 20 of the HR therapy cycle in both groups. In Group A, 3000 IU of hCG was administered on days 17, 20, and 23. In Group B, hCG was not used.ResultsThere was no significant difference in the average age of the patients, the average number of previous assisted reproductive technology cycles, or the average number of embryo transfers between the two groups. The rates of pregnancy and implantation per embryo were 37.2% and 25.3%, respectively, in Group A and 35.6% and 21.7%, respectively, in Group B. The pregnancy and implantation rates were similar in both groups.ConclusionSupplementation with hCG is not beneficial for cryopreserved‐thawed embryo transfer in estrogen/progesterone replacement cycles.

Эффективность программ вспомогательных репродуктивных технологий при переносе эмбрионов в стимулированном цикле по сравнению с переносом криоконсервированных/размороженных эмбрионов

Эффективность программ вспомогательных репродуктивных технологий при переносе эмбрионов в стимулированном цикле по сравнению с переносом криоконсервированных/размороженных эмбрионов

Clinical outcomes of intrafallopian transfer of cryopreserved-thawed embryos in a natural menstrual cycle in older females

Assisted reproductive technology (ART) in females aged 40 years or older is characterized by low pregnancy and high miscarriage rates. The impaired quality of the oocytes is thought to be the main cause, but the environment of the in vitro culture may be another factor. Considering this, we have carried out thawed embryos intrafallopian transfer (EIFT) in a natural cycle to expect embryogenesis under the most natural environment. In this study, we aimed to investigate whether intrafallopian transfer of thawed embryos in a natural menstrual cycle would improve the implantation rate in older females.

Higher success rates in thawed embryo transfer during natural cycle after cryopreservation of all fresh embryos

It is well known that transfer of cryopreserved-thawed embryos during a natural or a programmed cycle yields an excellent pregnancy rate. We therefore cryopreserved all embryos three or four days after oocyte retrieval (8cell∼morulla stage), thawed them when needed, and then maintained them in an in-vitro culture for one day prior to uterine transfer.

Retraction Note to: Can fresh embryo transfers be replaced by cryopreserved-thawed embryo transfers in assisted reproductive cycles? A randomized controlled trial

This article has been retracted at the request of the Editor and the ASRM Publications Committee, based on the results of an investigation which found serious methodological flaws in the study.

Letrozole stimulation in endometrial preparation for cryopreserved–thawed embryo transfer in women with polycystic ovarian syndrome: A pilot study

To study the efficiency of letrozole, an aromatase inhibitor, in endometrial preparation for cryopreserved-thawed embryo transfer (FET) in women with polycystic ovarian syndrome (PCOS). Retrospective observational study. One hundred and twenty patients with PCOS who met the inclusion criteria for the study. We assessed in vitro fertilization outcomes in one hundred and twenty patients with PCOS (148 cycles) who were prepared for and underwent FET between June 2011 and December 2012. Patients were prepared for FET using artificial hormone cycles induced with oestrogen and progesterone supplementation (n = 76), letrozole stimulation (n = 40) or hMG stimulation (n = 32). There were no differences in demographic characteristics between the groups, except that the letrozole group had a higher incidence of embryo transfer failure in the past. The letrozole stimulation group had a significantly higher maximal endometrial thickness and significantly higher rates of clinical pregnancy per transfer, ongoing pregnancy per transfer and implantation, compared with the artificial and hMG stimulation groups. Differences in these parameters between the artificial and hMG stimulation groups were not significant. Using letrozole stimulation in endometrial preparation for cryopreserved-thawed embryo transfer in patients with PCOS may be associated with better outcomes than using hormonal manipulation or hMG stimulation.

RETRACTED ARTICLE: Can fresh embryo transfers be replaced by cryopreserved-thawed embryo transfers in assisted reproductive cycles? A randomized controlled trial

Controlled ovarian hyperstimulation has been shown to advance endometrial maturation and adversely affects implantation in ART. It has been reported that there is a better embryo-endometrium synchrony in frozen-thawed embryo transfer cycles than fresh embryo transfer cycles. The objective of this study was to compare ongoing pregnancy rates between fresh ET and FET cycles. In an open prospective, controlled study, the patients who were classified as high responders, were randomized to either fresh ET or FET. The embryos in FET group were cryopreserved with vitrification by Cryotop method. A total of 374 patients were included, 187 of which were randomized to FET and 187 to fresh ET. There were 39% (n = 73) ongoing pregnancy in FET group compared with 27.8% (n = 52) in fresh ET group[odds ratio = 1.66;95% confidence interval = 1.07-2.56; p = 0.02]. FETs can be performed instead of fresh ETs to improve the outcome of ART in highly selected patients.

Impact of male age on the outcome of assisted reproductive technology cycles using donor oocytes

This study assessed the influence of the age of the male partner on the outcome of oocyte donation cycles. A total of 408 couples participating in 519 consecutive anonymous oocyte donation cycles were examined. Main outcome measures were fertilization rate, embryo quality, clinical pregnancy, implantation, miscarriage and live birth rates, as well as the total reproductive potential, which estimates the outcome from fresh and cryopreserved-thawed embryo transfers. A total of 241 cycles resulted in clinical pregnancy (48.5% of transfers). The mean embryo score for transferred embryos (ESTE) was higher in cycles resulting in pregnancy (P=0.003). Semen volume (P<0.001), sperm motility (P<0.001) and fertilization rate (P=0.04) decreased significantly with advanced male age, which did not correlate with mean ESTE or implantation rate. Fertilization rate was the only predictor of ESTE (B=16.066, P=0.012), whereas inseminated/retrieved egg ratio was the only predictor of implantation rate (B=0.555, P=0.039). Pregnancy was only predicted by ESTE (Exp(B)=1.023, P<0.001), which also was the only predictor of live birth (Exp(B)=1.017, P=0.009). There was no predictor of miscarriage (47 cycles, 9.1%) identified. Although semen volume, sperm motility and fertilization rate decreased with advanced male age, embryo quality, clinical pregnancy, implantation, miscarriage and live birth rates were not affected.

Complete globozoospermia associated with PLCζ deficiency treated with calcium ionophore and ICSI results in pregnancy

Globozoospermia is an infrequent pathology in which spermatozoa lack acrosomes. Patients are considered sterile without IVF augmented with intracytoplasmic sperm injection (ICSI), as fertilization is impaired due to absence of oocyte activation. As far as is known, this is the first study to report results of a comprehensive approach to the treatment of the semen parameters, sperm DNA fragmentation, aneuploidy, transmission electron microscopy, Western blotting and immunofluorescence for detection of phospholipase C zeta (PLCzeta), as well as ICSI outcome, of an affected patient. Morphological evaluation and transmission electron microscopy revealed complete globozoospermia with significant duplicate heads and tails. Analysis for DNA damage revealed fragmentation rates of approximately 80% in semen and 15-23% in swim-up fractions. PLCzeta was not detected by immunofluorescence or Western blotting. Aneuploidy rates were within normal ranges. ICSI followed by oocyte activation with calcium ionophore resulted in high rates of fertilization, and an ongoing pregnancy was established after transfer of cryopreserved-thawed embryos.

Higher success rates in thawed embryo transfer after in vitro culturing following cryopreservation of fresh embryos

OBJECTIVE: It is well known that transfer of cryopreserved-thawed embryos during a natural or a programmed cycle yields an excellent pregnancy rate. We therefore cryopreserved all embryos two days after oocyte retrieval, thawed them when needed, and then maintained them in an in-vitro culture for one day prior to uterine transfer.DESIGN: Retrospective clinical analysis of 564 cycles in 395 patients who received either thawed or fresh embryos.MATERIALS AND METHODS: Thawed embryo transfer (T) in 172 cycles (114 patients) and fresh embryo transfer (F) in 392 cycles (281 patients) randomly allocated to treatments with one of 3 kinds of controlled ovarian hyperstimulation methods [GnRH-antagonist + HMG-I, GnRH-agonist + FSH-Short (II'), Long (II'')] (following the ICSI) were analyzed. Thawed embryo transfer (T): All embryos recovered in hormone-stimulated cycles were cryopreserved according to the slow-cooling method (1.8 M ethylene glycol + 0.2 M sucrose) at the 4∼6 cell stage, and then, after thawing, transferred after one day of additional culture. Fresh embryo transfer (F): high quality embryo were transferred 3 days after the oocyte retrieval.RESULTS: The pregnancy and miscarriage rates in each group were as follows. [T-I: 51.9% (28/54), 17.9% (5/28)], [T-II': 56.4% (53/94), 9.4% (5/53)], [T-II'': 41.7% (10/24), 30.0% (3/10)], [F-I: 40.3% (50/124), 26.0% (13/50)], [F-II': 30.5% (72/236), 16.7% (12/72)], [F-II'': 43.8% (14/32), 21.4% (3/14)].CONCLUSIONS: The clinical success rates following the thawed embryo transfer were higher than those following the fresh embryo transfer in each COH method and was significantly higher in the group using GnRH-agonist-Short protocol. We believe that cryopreserving all embryos that are produced from the initial batch of collected oocytes and then transferred during the natural cycle will provide the best chance of a successful pregnancy. OBJECTIVE: It is well known that transfer of cryopreserved-thawed embryos during a natural or a programmed cycle yields an excellent pregnancy rate. We therefore cryopreserved all embryos two days after oocyte retrieval, thawed them when needed, and then maintained them in an in-vitro culture for one day prior to uterine transfer. DESIGN: Retrospective clinical analysis of 564 cycles in 395 patients who received either thawed or fresh embryos. MATERIALS AND METHODS: Thawed embryo transfer (T) in 172 cycles (114 patients) and fresh embryo transfer (F) in 392 cycles (281 patients) randomly allocated to treatments with one of 3 kinds of controlled ovarian hyperstimulation methods [GnRH-antagonist + HMG-I, GnRH-agonist + FSH-Short (II'), Long (II'')] (following the ICSI) were analyzed. Thawed embryo transfer (T): All embryos recovered in hormone-stimulated cycles were cryopreserved according to the slow-cooling method (1.8 M ethylene glycol + 0.2 M sucrose) at the 4∼6 cell stage, and then, after thawing, transferred after one day of additional culture. Fresh embryo transfer (F): high quality embryo were transferred 3 days after the oocyte retrieval. RESULTS: The pregnancy and miscarriage rates in each group were as follows. [T-I: 51.9% (28/54), 17.9% (5/28)], [T-II': 56.4% (53/94), 9.4% (5/53)], [T-II'': 41.7% (10/24), 30.0% (3/10)], [F-I: 40.3% (50/124), 26.0% (13/50)], [F-II': 30.5% (72/236), 16.7% (12/72)], [F-II'': 43.8% (14/32), 21.4% (3/14)]. CONCLUSIONS: The clinical success rates following the thawed embryo transfer were higher than those following the fresh embryo transfer in each COH method and was significantly higher in the group using GnRH-agonist-Short protocol. We believe that cryopreserving all embryos that are produced from the initial batch of collected oocytes and then transferred during the natural cycle will provide the best chance of a successful pregnancy.

Higher ongoing pregnancy rates in blastocyst transfer of frozen-thawed embryos in natural cycles than in hormone replacement therapy cycles

The aim of this study was to compare the outcome obtained from frozen-thawed embryo transfer in women submitted to two different protocols: natural cycle vs. HRT cycles. Retrospective study. This study comprised cryopreserved-thawed embryo transfer cycles performed at IVI Valencia from January 2000 to January 2006. Data were grouped in: Group I (n = 423) had frozen-thawed embryo transfer in a natural cycle and Group II (n = 707) frozen-thawed embryo transfer in a HRT cycle. The inclusion criteria were: (1) absence of uterine pathology, recurrent miscarriage and implantation failure; (2) non-severe sperm pathology; (3) endometrial thickness >6 mm at the day of the start of progesterone administration. The implantation, pregnancy and abortion rates of cryopreserved-thawed embryo were compared between the groups. We also analyzed these parameters depending on the day of the embryo transfer. Statistical analysis was performed by X2- test for categorical comparisons and Student's t-test to compare means between groups. A P value < 0.05 was considered significant. No differences were found in implantation and pregnancy rates between cryopreserved-thawed embryo in natural vs. HRT cycles (24%, IC 95% 20.3–28.3% vs. 22%, IC 95% 18.6%–26.1%) respectively. Pregnancy rate was 37.1%, IC 95% 32.5–41.7% vs. 39.7%, IC 95% 36.1–43.3) respectively. To evaluate if the stage of the embryo development may have some impact in the outcome, we compared 730 women (293 natural cycles vs. 437 HRT cycles) that were transferred at day 3 with 400 women (130 natural cycles vs. 270 HRT cycles) that were transferred at blastocyst stage. Pregnancy rate for cryopreserved embryo was 40% (IC 95% 34.4–45.6%) in a natural cycle and 45% (IC 95% 40.3–49.7%) in a HRT cycle. If cryopreserved blastocyst were transferred, pregnancy rate was 30% (IC 95% 22.1–37.9%) in a natural cycle and 38.5% (IC 95% 32.1–43.7%) in a HRT cycle, and no significant difference was found between both groups. However, abortion rate was 24% (39/157, IC 95% 17.3–30.7%) in women who had embryo transfer in a natural cycle and 39.4% (110/281; IC 95% 33.7–45.1%) in HRT. There were significant differences between the two groups with regard to the abortion rate (P<0.002). These findings suggest that both cryopreserved-thawed embryo transfer protocols are equally effective in terms of implantation and pregnancy rates. However, this is the first study that shows a significant difference regarding the abortion rate.

Transfer of Cryopreserved-Thawed Embryos in a Cycle Using Exogenous Steroids with or Without Prior Gonadotropihin-Releasing Hormone Agonist

Transfer of Cryopreserved-Thawed Embryos in a Cycle Using Exogenous Steroids with or Without Prior Gonadotropihin-Releasing Hormone Agonist

Clinical outcomes of two different endometrial preparation methods for cryopreserved‐thawed embryo transfer in patients with a normal menstrual cycle

Aim: To compare the clinical outcomes of cryopreserved-thawed embryo transfer among patients with a normal menstrual cycle who had natural or hormone-replacement cycles. Methods: From January 2004 to June 2006, cryopreserved embryos following conventional invitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) were thawed and transferred in a total of 720 natural cycles and 136 hormone-replacement cycles. Results: Cryopreserved-thawed embryo transfer in patients who had a natural or hormone-replacement cycle resulted in clinical pregnancy in 43.1% and 40.4%, respectively; a rate of miscarriage of 14.5% and 23.6%, respectively; and a rate of ongoing pregnancy and delivery of 36.5% and 30.9%, respectively. None of these differences were statistically significant. Conclusions: Patients with a normal menstrual cycle who have natural or hormone-replacement cycles can be expected to have comparable clinical outcomes with cryopreserved-thawed embryo transfer. (Reprod Med Biol 2007; 6: 53-57).

P-84: The impact of testicular spermatozoa for ICSI on the outcome of cryopresrved-thawed embryo transfers

The outcome of in- vitro fertilization with ICSI in terms of utilized spermatozoa origin has been demonstrated in numerous studies. More over, the effect of cryopreservation on the potential of spermatozoa was also addressed in this regard. However, the impact of surgically retrieved spermatozoa on the outcome of frozen-thawed embryo has not been elucidated thoroughly. Retrospective analysis Setting: Private IVF center. Three hundred eighty seven women undergoing cryopreserved thawed embryo transfer (CTET) in which ejaculated spermatozoa used for assisted fertilization were compared to 35 women undergoing CTET in which testicular spermatozoa used. Endometrium preparation with Estradiols and embryo transfer were interventions and implantation and pregnancy rates were regarded as main outcome measures. Mean age, duration of frozen embryo time, endometrial lining thickness, estradiol levels on embryo transfer day, number of embryos transferred and number of good quality embryos did not differ between groups. Two hundred two women conceived following ET in ejaculated spermatozoa used group and 17 women conceived in testicular spermatozoa used group. Both implantation and pregnancy rates were not found to be significantly different in evaluated groups. However multiple pregnancy rate is significantly higher in testicular spermatozoa used group (OR: 0.2, 95%CI: 0.09-0.7) (Figure I). Surgically retrieved spermatozoa do not deleteriously affect subsequent CTET outcome. Increased multiple pregnancy rate in this group should be carefully counseled with patients and number of transferred embryos could be reduced.

P-41: Effects of ovulation during endometrial preparation on the outcomes of cryopreserved-thawed blastocyst transfer cycles

Blastocyst transfer provides the ability to reduce the incidence of high order multiple pregnancy while optimizing pregnancy rates. Cryopreserved-thawed blastocyst transfer significantly may improve cumulative pregnancy rate. Cryopreserved-thawed embryo transfer has been successfully performed in ovulatory cycles such as natural cycles or ovulation induction cycles, and in non-ovulatory cycles in which the endometrium is artificially prepared with exogenous hormone supplementation. However, there are few available reports on the impact of ovulation during endometrial preparation in cryopreserved-thawed embryo transfer cycles. We compared clinical outcomes between ovulatory and non-ovulatory cycles to evaluate whether ovulation affected the outcomes during endometrial preparation in cryopreserved-thawed blastocyst transfer cycles. Prospective observational study. Sixty-eight patients who underwent cryopreserved-thawed blastocyst transfer from Jun 2005 to Mar 2006 were included in this study and divided into two groups: non-ovulatory group (n=33) and ovulatory group (n=35). In non-ovulatory group, endometrial preparation was achieved by oral estradiol valerate and intramuscular progesterone without prior gonadotropin-releasing hormone agonist suppression. Ovulatory group included natural cycles (n=17) and ovulation induction cycles using clomiphene citrate (n=9) or letrozole (n=9). We compared clinical characteristics and pregnancy outcomes, which were statistically analyzed using Mann-Whitney U-test and Fisher’s exact test where appropriate. The duration of endometrial preparation was significantly shorter in ovulatory group compared to non-ovulatory group (14.6±1.3 days vs. 13.9±1.7 days, p=0.042). Although there was no significant difference in the mean endometrial thickness on the day of progesterone or hCG administration between the two groups, triple endometrial patterns were more frequently observed in ovulatory group (18/33 (54.5%) vs. 30/35 (85.7%), p=0.007). However, there were no significant differences between the two groups with regard to the implantation and clinical pregnancy rates per embryo transfer.Tabled 1Tabled 1 These findings suggest that ovulation during endometrial preparation does not have any significant effect on the pregnancy outcomes. Both ovulatory and non-ovulatory cycles may be equally effective for endometrial preparation in cryopreserved-thawed blastocyst transfer cycles.