Outcome Of Frozen-thawed Embryo Transfer Research Articles

Factors affecting the outcome of frozen-thawed embryo transfer

Which clinical and laboratory factors affect live birth rate (LBR) after frozen-thawed embryo transfer (FET)? Top quality embryo characteristics, endometrial preparation protocol, number of embryos transferred and BMI affected independently the LBR in FET. FET is an important part of present-day IVF/ICSI treatment. There is limited understanding of the factors affecting success rates after FET. This is a two-centre retrospective cohort study. Analysis was carried out on 1972 consecutive FET cycles in 1998-2007, with embryos frozen on Day 2. The primary outcome was LBR per cycle. We assessed the independent effect on LBR of the following variables: female age, female age at embryo freezing, BMI, diagnosis, primary versus secondary infertility, fertilization by IVF versus ICSI, pregnancy in the fresh cycle, type (spontaneous, spontaneous with luteal progesterone and estrogen/progesterone substitution) and rank of the FET cycle, as well as number and presence (yes versus no) of top quality embryo(s) at freezing, thawing and transfer, damaged thawed embryos and overnight culture. In 78% of the cycles with top quality embryos frozen (n = 1319), at least one embryo still had high-quality morphology after thawing. Top quality embryo morphology observed at any stage of culture improved the outcome even if high-quality characteristics disappeared before transfer. LBRs after the transfer of a top quality embryo were similar in the FET (24.9%) and fresh cycles of the same period (21.9%). The chance of live birth increased significantly if ≥1 top quality embryo was present at freezing (odds ratio (OR) 1.85, 95% confidence interval (CI) 1.10-3.14), at thawing (OR 1.93, CI 1.20-3.11) or at transfer (OR 3.41, CI 2.12-5.48). Compared with spontaneous cycles with luteal support, purely spontaneous cycles (OR 0.58, CI 0.40-0.84) and hormonally substituted FET (OR 0.47, CI 0.32-0.69) diminished the odds of pregnancy. BMI (OR 0.96, CI 0.92-0.99) and transfer of two embryos versus one (OR 1.45, CI 1.08-1.94) were other factors that improved LBR after FET. The sample sizes available in some subanalyses were small, limiting the power of the study. The presence of ≥1 top quality embryo at any step of the freezing and thawing process increases the chance of pregnancy. The data do not support the freezing of all embryos for transfer in order to improve the outcome. A top quality embryo transferred in FET may even have the same potential as in a fresh cycle. On the contrary, LBR in the group with no top quality embryos frozen was quite low (10.4%), raising the question of whether a re-evaluation of freezing criteria is necessary to avoid costly treatments with a low success rate.

Luteal phase support does not improve the clinical pregnancy rate of natural cycle frozen-thawed embryo transfer: a retrospective analysis

ObjectiveTo evaluate pregnancy outcomes with and without use of luteal phase support (LPS) in frozen-thawed embryo transfer (FET) performed in natural cycles (NC). Study designRetrospective analysis. Before 1st July 2009, two doses of 1500IU intramuscular human chorionic gonadotrophin were given on the day of FET and 6 days after the transfer. Such practice was stopped after 1st July 2009. The pregnancy outcomes of NC FET with and without LPS were compared. ResultsA total of 408 NC FET cycles were analysed. Demographic data, embryo quality, clinical pregnancy rates and miscarriage rates were comparable with and without LPS. By univariate logistic regression, the only significant factors predicting the clinical pregnancy rate were the women's age, the number of embryos transferred, the number of top quality embryos before and after cryopreservation, and the average number of blastomeres after thawing. Only the women's age (OR 0.944, 95%C.I. 0.893–0.998, p=0.044) remained to be a significant predictor of clinical pregnancy rate by multivariate logistic regression. ConclusionThe pregnancy outcomes of NC FET were similar with or without LPS. The women's age was the significant factor affecting the clinical pregnancy rate. A randomised trial should be carried out to confirm the results.

Outcome of frozen-thawed embryo transfer in natural cycles with spontaneous ovulation versus hCG triggering and hormone replacement therapy

Outcome of frozen-thawed embryo transfer in natural cycles with spontaneous ovulation versus hCG triggering and hormone replacement therapy

Patients undergoing frozen-thawed embryo transfer have similar live birth rates in spontaneous and artificial cycles

To evaluate the outcome of frozen-thawed embryo transfer (FET) when freezing takes place at the pronuclear stage, a retrospective analysis was performed comparing spontaneous and artificial cycles. 148 women received FET in a spontaneous cycle (Group A) and 55 women received FET in an artificial cycle (Group B) induced by administering estrogen (E2) and progesterone (P). Pregnancy rates, endometrial thickness and serum levels of E2, P and luteinizing hormone (LH) were measured. Statistical analysis included the mean, the standard deviation, the Chi-squared test and the T-test. The clinical pregnancy rate was 34.5% for Group A and 21.8% for Group B (p = 0.084), with a live birth rate of 20.9% and 12.7% respectively (p = 0.15). There was no difference in endometrial thickness or the P levels, while LH and E2 levels were significantly higher in group B (p < 0.0001). Our retrospective study shows a trend towards higher pregnancy rates and live birth rates with the administration of FET during a spontaneous cycle compared to FET during an artificial cycle. Large randomized controlled trials are needed to confirm this trend.

Blastocyst transfer in frozen-thawed cycles.

ObjectiveIt is well known that fresh blastocyst transfer results in better pregnancy outcomes with a smaller number of transferred embryos compared with cleavage stage embryo transfer. However, in terms of frozen-thawed blastocyst transfer, only a few studies are available. We aimed to evaluate clinical outcomes of frozen-thawed embryo transfer (FET) with blastocysts.MethodsRetrospective analysis of FET cycles with blastocysts (B-FET) between Jan 2007 and June 2009 was performed. Age-matched FET cycles with cleavage stage embryos (C-FET) during the same period were collected as controls. A total of 58 B-FET cycles were compared with 172 C-FET cycles and also compared with those of post-thaw extended culture blastocysts from frozen pronuclear stage embryos (22 cycles).ResultsThere was no difference in the patient characteristics of each group. The embryos' survival rates after thawing were comparable (>90%) and there was no difference in the implantation rate or clinical and ongoing pregnancy rate among the three groups.ConclusionIn FET, blastocyst transfers may not present better pregnancy outcomes than cleavage stage embryo transfers. A further large-scale prospective study is needed.

Natural cycle is superior to hormone replacement therapy cycle for vitrificated-preserved frozen-thawed embryo transfer

We undertook this retrospective variables-control analysis to compare the reproductive outcomes of frozen-thawed embryo transfer using endometrial preparation with either natural cycle or hormone replacement therapy cycle. Patients were divided into three subgroups. Subgroup A (n = 32) consisted of patients having three 8-cell post-thawed embryos transferred. Subgroup B (n = 404) consisted of patients having three good quality post-thawed embryos transferred. Subgroup C (n = 578) consisted of patients having two or three all intact and mitosis resumption post-thawed embryos transferred. Implantation rate, biochemical pregnancy rate, and clinical pregnancy rate were measured. In subgroup A, significantly higher implantation rate, clinical pregnancy rate ongoing pregnancy rate, and lower biochemical pregnancy rate were observed in the natural cycle compared with hormone replacement therapy (HRT) cycle. Subgroup B, had a significantly higher rate of implantation, ongoing pregnancy, and a significantly lower rate of biochemical pregnancy in natural cycle compared with HRT cycle. The natural cycle had a higher trend of clinical pregnancy rate without reaching statistical significance. No statistical difference in reproductive outcomes between natural cycle and HRT cycle was observed in subgroup C. The results suggest the superiority of the natural cycle as compared with the HRT cycle under certain circumstances in a selected population of patients.

A comparative study on the impact of fresh variables on the success of frozen-thawed embryo transfer cycles using 2PN sibling embryos in women with/without polycystic ovary syndrome

Aims: The aim of the present study was to identify the fresh variables that influence the frozen-thawed embryo transfer (FET) outcome using sibling two pronuclei (2PN) embryos in women with polycystic ovary syndrome (PCOS) and non-PCOS women. Material & methods: Fifty-five FET cycles were performed using sibling embryos randomly cryopreserved at 2PN states and basal/cycle characteristics of fresh variables were compared between PCOS and non-PCOS groups according to the success in FET pregnancy: group A (pregnant PCOS); group B (not pregnant PCOS); group C (pregnant non-PCOS); group D (not pregnant non-PCOS). Results: In PCOS patients, higher progesterone level on human chorionic gonadotropin (hCG) day was observed in group A than in group B (0.9 ± 0.0 vs. 0.5 ± 0.3, p = 0.004). In non-PCOS patients who achieved a pregnancy in the fresh cycle, a subsequent FET cycle using sibling 2PN embryos conferred a thirteen times increased chance of achieving pregnancy (OR 13.0; 95% CI, 2.3–74.1). Embryo quality and endometrial maturation were comparable between A and B or C and D. Conclusions: The success of the fresh embryo transfer (ET)was the most important predictor of pregnancy in FET cycles in the non-PCOS group. The relationship between serum progesterone on hCG day in the fresh cycle and the outcome of subsequent FET would benefit further evaluation in PCOS group.

The impact of the duration of estrogen supplementation on the outcome of medicated frozen-thawed embryo transfer (FET) cycles

The impact of the duration of estrogen supplementation on the outcome of medicated frozen-thawed embryo transfer (FET) cycles

Impact on outcome of frozen-thawed embryo transfer by reducing numbers of transferred embryos

To study the impact on pregnant outcome of reducing the number of embryos transferred from three to two in women at age less than 35 who received frozen-thawed embryo transfer (FET). The analysis was performed on 90 FET cycles (77 infertile couples, less than 35 years old) with slow-freezing/rapid-thawing method, including 48 cycles with two embryos transferred and 42 cycles with three embryos transferred. The embryo survival rate, high quality embryo rate, clinical pregnancy rate, implantation rate and multiple pregnancies rate were analyzed. No significant differences in embryo survival rate (88.9% versus 88.1%), high quality embryo rate (89.6% versus 81.0%), clinical pregnancy rate (37.5% versus 42.9%), implantation rate (26.0% versus 18.3%) and multiple pregnancy rate (38.9% versus 16.7%) were observed between two and three embryos transferred group (all P > 0.05). However, there were 2 triple pregnancies in three embryos transferred group while none in two embryos transferred group. Reducing the number of high quality embryos transferred from three to two in women at age of less than 35 years old who received FET, could decrease the incidence of triple pregnancy and keep the similar clinical pregnancy rate.

GnRH-agonist down-regulation is not essential for the success of frozen embryo transfers

OBJECTIVE: To compare outcomes of frozen-thawed embryo transfer (FET) cycles prepared with or without GnRH down-regulation prior to and during endometrial preparation. DESIGN: A retrospective analysis of two protocols for endometrial preparation during FET cycles. MATERIALS AND METHODS: Between Sept. 2005 and Feb. 2008, GnRHa was used during endometrial preparation (group 1, 102 cycles). Briefly, administration of Lupron 1 mg daily began during the mid-luteal phase and of Estradiol Valerate (EV) 2 to 4 mg every-other-day intramuscularly (IM) began at day-5 of the following menstrual cycle. When endometrial thickness reached ≥8mm, Lupron was discontinued and progesterone in oil 100mg daily was administered IM together with the EV. Embryos were transferred on the 6th day of progesterone administration. Between Feb. 2008 and Dec. 2009, GnRHa was omitted (group 2, 94 cycles). Pregnancy outcomes were compared between these two protocols. RESULTS: Mean patient age (35.0 ± 5.46 vs 35.1 ± 5.38) was not different between group 1 and 2. FET cycles in group 1 had slightly thicker maximal endometrium (11.37 ± 1.58 mm) than in group 2 (10.97 ± 1.45 mm, P=0.004). Also more embryos were transferred in group 1 than in group 2 (2.21 ± 0.57 vs 2.04 ± 0.50, P=0.03). Clinical pregnancy, ongoing pregnancy rates (64.1% vs 57.9% and 57.3% vs 51.6% respectively) were slightly higher in the group 1 than in group 2, but there were no statistical significances (P>0.05). The implantation rate (35.5% vs 36.1%, P>0.05) was slightly lower in group 1 than in group 2. Furthermore, very few cycles exhibited follicular growth during endometrial preparation for both protocols and there were no mature follicles at the onset of progesterone administration in either group. CONCLUSION: GnRHa down-regulation prior to and during endometrial preparation for FET is not beneficial and may be omitted for routine frozen embryo transfer cycles. The slightly lower pregnancy outcome in the non-GnRHa group is most likely the result of slightly fewer embryos transferred in this group.

Factors affecting the outcome of frozen-thawed embryo transfer

OBJECTIVE: The relative importance of factors which affect frozen-thawed embryo transfer (FET) is poorly understood. The aim of the study was to identify which characteristics of the fresh and frozen cycles affect the chance of pregnancy in FET.

Serum progesterone on the day of human chorionic gonadotropin administration predicts clinical pregnancy of sibling frozen embryos

To evaluate patient characteristics and fresh in vitro fertilization (IVF) cycle parameters that influence success of sibling frozen-thawed embryo transfer (FET) cycles. Retrospective study. Academic infertility practice. Infertile women undergoing FET cycles using embryos cryopreserved on day 3 after insemination after an initial fresh IVF cycle. 90 FET cycles. Clinical pregnancy (CP). The likelihood of CP after FET was statistically significantly higher in women who had achieved CP in the preceding fresh IVF cycle (71.4% vs. 40.6%). Multivariable logistic regression analysis confirmed that patients achieving CP after the fresh IVF cycle were more likely to achieve CP after FET (OR 5.5; 95% CI, 1.2-25.3) after adjusting for age, number, and cleavage status of embryos transferred. Additionally, higher serum levels of progesterone on the day of human chorionic gonadotropin administration emerged as predictive of CP after FET at a statistically significant level. The outcome of the fresh embryo transfer cycle is the foremost predictor of CP after FET of the sibling embryos. The relationship between serum progesterone on the day of human chorionic gonadotropin administration in the fresh cycle and the outcome of subsequent FET is noteworthy and merits further investigation.

Effect of luteinized unruptured follicle cycles on clinical outcomes of frozen thawed embryo transfer in Chinese women

To determine the effect of luteinized unruptured follicle (LUF) cycles on frozen thawed embryo transfer (FET). A retrospective analysis comparing the clinical outcomes after FET among 144 cases of luteinized unruptured follicle (LUF) cycles and 866 cases of ovulation cycles. Reproductive medical center, Beijing China. Chinese infertile women who underwent FET. None. Clinical pregnancy rate (PR), implantation rate. The implantation rate, clinical pregnancy rate, on-going pregnancy rate and live birth rate in LUF group were 12.76% (49/384), 27.78% (40/144), 24.31% (35/144) and 19.44% (28/144), respectively, and in ovulation group, 14.74% (332/2251), 31.29% (271/866), 28.29% (245/866) and 22.23% (193/866), respectively (p > 0.05). LUF does not affect the clinical outcomes of FET. Patients of LUF should be included in FET treatment.

Influence of Embryo Quality on the Outcome of Frozen-thawed embryo Transfer

目的 探讨移植胚胎数量和质量与对冻融胚胎移植结局的影响.方法 回顾性分析2004年间用慢冻快融的方法所进行的265个冻融胚胎移植周期结果,并与同期新鲜胚胎移植周期比较两者的临床妊娠率、种植率、多胎率等.结果 :(1)移植3个胚胎组的临床妊娠率、多胎率、种植率分别为35.19%、36.84%、16.67%,与移植≤2个胚胎组的24.49%、16.67%、15.48%的差异均无显著性(P＞0.05).移植3个优质胚胎组的多胎率为40.82%明显高于移植≤2个优质胚胎组的23.08%(P＜0.01),但两者的临床妊娠率和种植率均无显著性差异(P＞0.05).(2)妊娠组胚胎完好率、优质胚胎率分别为46.97%,68.18%显著高于非妊娠组的40.65%,55.91%(P＜0.05).而两者的复苏率分别为84.24%、79.09%,无显著性差异(P＞0.05).(3)与同期新鲜胚胎移植周期的种植率27.62%比较,冻融胚胎移植的种植率13.28%显著降低(P＜0.01).结论 冻融胚胎移植周期的多胎妊娠率与移植的优质胚胎数目有关,与移植胚胎数目无关.冷冻胚胎移植的种植率显著低于新鲜胚胎移植,两者的临床妊娠率及多胎率均无差别。

Postthaw Embryo Compaction is Predictive of the Success of Frozen-Thawed Transfer

Although cryopreservation of supernumerary embryos has increased the overall success rate in human IVF-ET, the survival and implantation rate of frozen-thawed embryos is directly related to the quality of embryos at the time of freezing. Overnight incubation improves selection of good quality embryos for transfer. Studies showed that there was a ∼45% implantation rate for day 4 embryos after fresh morula ET. This study is designed to investigate the predictors of postthaw embryo compaction and the relationship to the outcome of frozen-thawed embryo transfer (FET) cycles.

Prevalence of premature urinary luteinizing hormone surges in women with regular menstrual cycles and its effect on implantation of frozen-thawed embryos

To determine the frequency and effect of premature luteinizing hormone (LH) surges on pregnancy rates in women with regular menstrual cycles. Retrospective cohort study. Assisted Reproductive Technology Program at private medical college. Regularly menstruating women undergoing frozen embryo transfer (ET). Detection of urinary LH surges with an RIA kit during natural-cycle frozen-embryos transfer. Incidence of premature LH surges and pregnancy outcomes. Eighty-eight (46.8%) of 188 regularly menstruating women had premature LH surges and 33 (37%) of those 88 had multiple premature LH surges. Pregnancy rates per ET are similar between women with and without premature LH surges. A high percentage of normally cycling women demonstrate premature urinary LH surges without an effect on outcome of frozen-thawed ETs.

Postthaw blastomere survival is predictive of the success of frozen–Thawed embryo transfer cycles

To investigate the predictors of postthaw blastomere survival and the relationship of blastomere survival to the outcome of frozen-thawed embryo transfer (FET) cycles. Retrospective study. An IVF unit in a tertiary care facility. Infertile women undergoing FET cycles with embryos cryopreserved on day 3 postinsemination. FET cycles. Embryo survival postthaw, pregnancy (PR), clinical pregnancy, and implantation rates. A significant impact of postthaw blastomere survival on the outcome of FET cycles was noted. The thawed embryos in the low survival tertile resulted in significantly impaired implantation rate, clinical pregnancy rate, and PR compared to embryos in the high survival tertile. An inverse association was noted between serum P levels on the day of hCG administration and postthaw blastomere survival. We have demonstrated that postthaw blastomere survival is predictive of success of FET cycles. The relationship of poor postthaw embryo survival in the setting of elevated P is novel and not hitherto described.