Trade-off between double cleavage-stage embryos transfer and single blastocyst-stage embryo transfer in patients with few good quality embryos in antagonist cycles: a retrospective study using a propensity score matching analysis.

OBJECTIVE: This study aimed to compare the per OPU clinical outcomes for transfer of Day 3 double cleavage-stage embryos (DET) and Day 5 single blastocyst-stage (SBT) in patients with five or fewer good quality embryos on day 3 per occyte pick-up cycle (OPU) in antagonist cycles with consideration of blastocyst formation failure. METHODS: This was a retrospective, observational cohort study of 2,116 cases of OPU treated with antagonist protocol in the affiliated Chenggong Hospital of Xiamen University between January 2013 and December 2020. DET was performed in 1,811cycles and SBT was performed in 305 cycles. The DET group was matched to the SBT group by propensity score (PS) matching according to multiple maternal baseline covariates. After PS matching, there were 303 ET cycles in each group. The primary outcomes were the cumulative live birth rate (CLBR), cumulative multiple pregnancy rate(CMPR)per OPU and the number of ET to achieve live birth per OPU. Secondary outcomes were the percentage of clinical pregnancy(CPR), live birth rate(LBR), multiple pregnancy rate(MPR). RESULTS: Following PS mating, the CLBR was slightly higher (48.8% versus 40.3% ; P = 0.041) and the CMPR was significantly higher in the DET group compared to SBT group(44.2% versus 7.9%, P < 0.001). The CPR, LBR and MPR per fresh transfer were higher in DET group compared to SBT group(50.2% versus 28.7%; 41.3% versus 21.5%;29.6% versus 0%, P < 0.001). The number of ET to achieve live birth per OPU in SBT group was obiviously more than in DET group(1.48 ± 0.578 versus 1.22 ± 0.557 ,P < 0.001). CONCLUSION: With a marginal difference cumulative live birth rate, the lower live birth rate per fresh transfer and higher number of ET per OPU in the SBT group suggested that it might take longer time to achieve a live birth with single blastocyst strategy. A trade-off decision should be made between efficiency and safety.

Maternal and obstetric outcomes following the transfer of embryos warmed with fatty acid-supplemented solutions.

BACKGROUND: Vitrification procedures decrease intracytoplasmic lipid content and impair developmental competence. Adding fatty acids (FAs) to the warming solution has been shown to recover the lipid content of the cytoplasm and improve developmental competence and pregnancy outcomes. However, the influence of the FA supplementation on live birth rates after embryo transfers and perinatal outcomes remains unknown. In the present study, we examined the influence of FA-supplemented warming solutions on live birth rates, pregnancy complications, and neonatal outcomes after single vitrified-warmed cleavage-stage embryo transfers (SVCTs). METHODS: The clinical records of 701 treatment cycles in 701 women who underwent SVCTs were retrospectively analyzed. Vitrified embryos were warmed using solutions (from April 2022 to June 2022, control group) or FA-supplemented solutions (from July 2022 to September 2022, FA group). The live birth rate, pregnancy complications, and perinatal outcomes were compared between the control and FA groups. RESULTS: The live birth rate per transfer was significantly higher in the FA group than in the control group. Multivariate logistic regression analysis further demonstrated a higher probability of live births in the FA group than in the control group. Miscarriage rates, the incidence and types of pregnancy complications, the cesarean section rate, gestational age, incidence of preterm delivery, birth length and weight, incidence of low birth weight, infant sex, and incidence of birth defects were all comparable between the control and FA groups. Multivariate logistic regression analysis further demonstrated no adverse effects of FA-supplemented warming solutions. CONCLUSIONS: FA-supplemented warming solutions improved live birth rates after SVCTs without exerting any adverse effects on maternal and obstetric outcomes. Therefore, FA-supplemented solutions can be considered safe and effective for improving clinical outcomes and reducing patient burden.

Number of embryos transferred could possibly be associated with angular pregnancy in in vitro fertilization-embryo transfer.

OBJECTIVE: The probability of embryo implantation in an abnormal location is significantly higher in assisted reproductive technology (ART) than in natural pregnancies. Angular pregnancy is an eccentric intrauterine pregnancy with embryo implantation in the lateral superior angle of the uterine cavity. Cycle-level factors associated with angular pregnancy in patients conceived with ART needed to be explored. METHODS: A total of 11 336 clinical pregnancies cycles were included. Angular pregnancy rate was compared among groups according to the type of embryos transferred. Among them, 53 cases of angular pregnancy and 159 cases of normal intrauterine pregnancy were screened out using propensity score matching. Risk factors of angular pregnancy were explored. RESULTS: The angular pregnancy rate was 0.31% (14/4572) in the day 5 blastocyst transfer group, 0.58% (39/6764) in non-day 5 embryo transfer group, with 0.55% (29/5280) in day 3 embryo transfer and 0.67% (10/1484) in the day 6 blastocyst group, respectively. A multifactor regression analysis was performed and indicated that the number of embryos transferred was significantly associated with angular pregnancy (P = 0.031, OR, 2.23, 95% CI: 1.09-4.68). CONCLUSION: Multiple embryo transfer could possibly be associated with an increased incidence of angular pregnancy in patients conceived with ART.

Sequential embryo transfer versus double cleavage-stage embryo or double blastocyst transfer in patients with recurrent implantation failure with frozen-thawed embryo transfer cycles: a cohort study.

Background: Recurrent implantation failure (RIF) is more common among patients receiving assisted reproductive treatment. Many efforts have been made to increase the incidence of clinical pregnancy among patients with RIF. The effect of the sequential transfer procedure, a two-step interval transfer of a cleavage-stage embryo followed by a blastocyst in one transfer cycle, on the clinical outcomes of RIF patients remains controversial. Methods: In total, 1774 frozen-thawed embryo transfer (FET) cycles in RIF patients were included. Of these cycles, 302 were sequential embryo transfer (ET) cycles, 979 were double day 3 cleavage-stage ET cycles, and 493 were double blastocyst ET cycles. The primary outcomes were the rates of implantation, clinical pregnancy and multiple pregnancy, and the secondary outcomes were the rates of hCG positive, early miscarriage and ectopic pregnancy. Results: The implantation, hCG positive, and clinical pregnancy rates in the sequential ET group (32.1%, 58.9%, 50.7%) were significantly higher than those in the day 3 cleavage-stage ET group (24.9%, 46.5%, 40.4%) and were similar to those in the blastocyst transfer group (30.1%, 56.4%, 47.1%). The early miscarriage rate in the blastocyst transfer group was significantly higher than that in the cleavage-stage ET group (17.2% vs. 8.1%, P <0.05), while the ectopic pregnancy rate in the blastocyst transfer group was significantly lower than that in the cleavage-stage ET group (0.4% vs. 3.0%, P <0.05). The multiple pregnancy rate in the sequential ET group was significantly lower than that in the cleavage-stage ET group (17.0% vs. 25.5%, P <0.05) and the blastocyst transfer group (17.0% vs. 27.6%, P <0.05). When cycles of blastocyst culture failure were excluded, the clinical pregnancy rate was significantly higher (55.7% vs. 47.1%, P <0.05), and the early miscarriage rate and multiple pregnancy rate were significantly lower (8.5% vs. 17.2%, 17.7% vs. 27.6%; P <0.05, respectively) in the sequential ET group than in the double blastocyst ET group. Conclusions: Sequential embryo transfer in FET cycles could improve the clinical outcomes of patients with RIF.

Noninvasive embryo evaluation and selection by time-lapse monitoring vs. conventional morphologic assessment in women undergoing in vitro fertilization/intracytoplasmic sperm injection: a single-center randomized controlled study.

OBJECTIVE: To determine whether time-lapse monitoring (TLM) for cleavage-stage embryo selection improves reproductive outcomes in comparison with conventional morphological assessment (CMA) selection. DESIGN: Prospective randomized controlled trial. SETTING: Single academic center. PATIENTS: We randomly assigned 139 women who were undergoing their first in vitro fertilization or intracytoplasmic sperm injection cycle to undergo either fresh embryo transfer or first frozen embryo transfer (FET). Only 1 cleavage-stage embryo was transferred to each participant. INTERVENTIONS: The patients were randomly assigned to either the CMA or the TLM group. In the CMA group, day 2 and day 3 embryos were observed. A good-quality cleavage-stage embryo was selected for transfer or freezing in both groups. MAIN OUTCOME MEASURES: The primary and secondary outcomes were the clinical pregnancy rate (CPR) and the live birth rate (LBR), respectively, after the first embryo transfer (fresh embryo transfer or FET). RESULTS: The CPR and LBR were significantly lower in the TLM group than in the CMA group (CPR: 49.18% vs. 70.42%; relative risk, 0.70; 95% confidence interval [CI], 0.52-0.94; LBR: 45.90% vs. 64.79%; relative risk, 0.71; 95% CI, 0.51-0.98). The CPR with fresh embryo transfer or FET did not significantly differ between the TLM and the CMA groups (fresh embryo transfer: 44.44% vs. 70.0%, relative risk, 0.63, 95% CI, 0.39-1.03; FET: 52.94% vs. 70.73%, relative risk, 0.75, 95% CI, 0.52-1.09). There was a significant difference in the LBR with fresh embryo transfer between the TLM and the CMA groups (40.74% vs. 66.67%; relative risk, 0.61; 95% CI, 0.36-1.03). The LBRs with FET were similar in the TLM and the CMA groups (50.0% vs. 63.41%; relative risk, 0.79; 95% CI, 0.52-1.19). The rates of early spontaneous abortion and ectopic pregnancy did not differ between the TLM and the CMA groups. CONCLUSIONS: Elective single cleavage-stage embryo transfer with TLM-based selection did not have any advantages over CMA when day 2 and day 3 embryo morphology was combined in young women with a good ovarian reserve. Because of these results, we conclude that TLM remains an investigational procedure for in vitro fertilization practice. CLINICAL TRIAL REGISTRATION NUMBER: ChiCTR1900021981.

Blastocyst versus cleavage embryo transfer improves cumulative live birth rates, time and cost in oocyte recipients: a randomized controlled trial.

RESEARCH QUESTION: Does embryo transfer day (day 5 versus day 3) affect cumulative live birth rates (CLBR), time to live birth (TLB) and cost per live birth (CPL) in recipients of donated oocytes? STUDY DESIGN: A single-centre RCT conducted between April 2017 and August 2018. Recipients of donated oocytes were randomized to cleavage-stage (day 3) or to blastocyst-stage (day 5) embryo transfer. Eligible recipients were aged 18-50 years and in their first or second synchronous cycle. Primary outcome was CLBR (12 months from first embryo transfer), and fresh and subsequent cryopreserved transfers were considered; TLB and CPL were also analysed. RESULTS: Recipients (n = 134) were randomized to the day-3 group (n = 69) or to the day-5 group (n = 65). Day-5 transfer resulted in a 15.9% relative increase in CLBR and a significant shorter TLB compared with day-3 transfer. To reach a 50% CLBR, the day-3 group required 6 months more than the day-5 group (15.3 versus 8.9 months, respectively). The average CPL in the day-3 strategy cost 24% more than the day-5 strategy (€14817.10 versus €10959.20). Clinical pregnancy rate was 25% less in the day-3 group. The trial was prematurely stopped after poor initial results in the day-3 arm led to unplanned interim analysis. CONCLUSIONS: The transfer of blastocyst-stage embryos in recipients of donated oocytes is preferred as it leads to a higher clinical pregnancy rate, live birth rate, shorter time to pregnancy and lower costs to achieve live birth, compared with cleavage-stage embryo transfer.

Clinical outcomes for Day 3 double cleavage-stage embryo transfers versus Day 5 or 6 single blastocyst transfer in frozen-thawed cycles: a retrospective comparative analysis.

OBJECTIVE: This study aimed to compare the clinical outcomes for transfer of Day 3 (D3) double cleavage-stage embryos and Day 5/6 (D5/6) single blastocysts in the frozen embryo transfer (FET) cycle to formulate a more appropriate embryo transplantation strategy. METHODS: We retrospectively analyzed 609 FET cycles from 518 women from April 2017 to March 2021. All FETs were assigned to the D3-DET group (transfer of a Day 3 double cleavage-stage embryo), D5-SBT group (transfer of a Day 5 single blastocyst), or D6-SBT group (transfer of a Day 6 single blastocyst). Clinical outcomes were comparatively analyzed. RESULTS: There were no significant differences in the biochemical pregnancy rate, clinical pregnancy rate, or ongoing pregnancy rate between the D3-DET and D5-SBT groups, but these rates in the two groups were all significantly higher compared with those in the D6-SBT group. The implantation rate in the D5-SBT group was significantly higher than that in the D3-DET group. The twin pregnancy rate in the D5-SBT and D6-SBT groups was significantly lower than that in the D3-DET group. CONCLUSION: This study suggests that D5-SBT is the preferred option for transplantation. D6-SBT reduces the pregnancy rate, making it a more cautious choice for transfer of such embryos.

Frozen blastocyst embryo transfer vs. frozen cleavage-stage embryo transfer in couples with recurrent implantation failure: a cohort study.

The objective of this prospective cohort study was to investigate whether cryopreservation of cleavage or blastocyst stage embryos improves in vitro fertilization outcomes in recurrent implantation failure (RIF) patients. The study comprised 575 patients who were allocated to receive either single frozen/thawed blastocyst-stage transfer (SBT) or frozen/thawed double-cleavage-stage embryo transfer (DET). The clinical pregnancy rate, implantation rate, and ongoing pregnancy rate were higher in the SBT group compared with the DET group (41.15% vs. 27.11%, p < 0.001; 41.15% vs. 19.28%, p < 0.001; 40.03% vs. 25.9%, p < 0.001), but the miscarriage rate did not differ between the two groups. It was concluded that frozen/thawed SBT could be a preferred strategy for RIF patients.

Comparison of clinical outcome between 2 and 3 embryos transfer for elderly women / 解剖学报

Objective To explore the relationship between clinical outcomes and embryo transfer number, and to provide some proposals for transfer selection of elderly patients. Methods Data from 80 fresh transfer cycles with cleavage-stage embryos were analyzed. Cycles were divided into several groups according to transfer number. Clinical pregnancy rate, implantation rate, multiple pregnancy rate and live birth rate were compared. Results To women no younger than 38 years old, when available embryo number was larger than two, similar clinical outcomes could be achieved by transferring two and three embryos. This trend was independent of the number of transferred 8-cell embryos. Conclusion The number of fresh cleavage-stage embryos transfer should not exceed two in elderly women.

Comparison of perinatal outcomes following blastocyst and cleavage-stage embryo transfer: analysis of 10 years' data from a single centre.

RESEARCH QUESTION: Are there greater risks of adverse perinatal outcomes, in particular of congenital malformations, after blastocyst transfer compared with cleavage-stage embryo transfer in IVF? DESIGN: This was a retrospective cohort analysis from a centre for assisted reproduction at a public hospital in China over the period 2006-2015. The analysis covered all women who conceived (15,254) and newborns (16,213) from IVF/intracytoplasmic sperm injection (ICSI) cycles with cleavage-stage embryo transfer or blastocyst transfer. The principal outcome measures were congenital malformations, preterm birth (PTB), low birthweight (LBW), small for gestational age (SGA) and large for gestational age (LGA). RESULTS: Logistic regression analysis showed that the sex ratio was imbalanced towards male neonates after blastocyst transfer (P=0.001; adjusted OR 1.17, 95%CI 1.07-1.30) but there were no differences in rates of miscarriage, ectopic pregnancy, stillbirth, very preterm birth (<32 weeks), PTB (<37 weeks), LBW, SGA or LGA between blastocyst transfer and cleavage-stage embryo transfer. A total of 176 congenital malformations (123 cleavage-stage embryos versus 53 blastocysts) were identified both in newborns and aborted fetuses, but the difference between groups was not statistically significant. CONCLUSIONS: There was no difference in the risks of adverse perinatal outcomes, and in particular of congenital malformation, after blastocyst transfer compared with cleavage-stage transfer, although there was a sex ratio imbalance towards male neonates after blastocyst transfer.

Comparison of the pregnancy and obstetric outcomes between single cleavage-stage embryo transfer and single blastocyst transfer by time-lapse selection of embryos.

To compare the pregnancy and obstetric outcomes following single cleavage-stage embryo transfer (SCT) and single blastocyst transfer (SBT) using time-lapse imaging (TLI), a total of 2066 normally fertilized and cleaved embryos from 233 patients were divided into Day 3 SCT group (n = 171) and Day 5 SBT group (n = 62) according to patient's willingness. Embryo selection criteria were based on embryo cleavage patterns, timing parameters, and blastocyst quality. The pregnancy and obstetric outcomes of each group were evaluated. There were no statistically significant differences with regard to pregnancy outcomes including the implantation rate, early abortion rate, ongoing pregnancy rate and live birth rate, and obstetric outcomes including preterm birth rate, gestational week, birth height, birth weight and fetal malformation rate between SCT group and SBT group. SBT group had significantly higher monozygotic twinning (MZT) rates than SCT group (6.98% vs. 0, p < .05). Although not statistically significant, there was a trend of higher proportion of male-to-female sex ratio at birth in SBT group than SCT group (1.38 vs. 1.05). Based on the combination of cleavage patterns and timing parameters, SCT may be an alternative to SBT because it can provide similar pregnancy and obstetric outcomes and meanwhile lower monozygotic twinning rates.

The effect of blastocyst transfer on newborn sex ratio and monozygotic twinning rate: an updated systematic review and meta-analysis.

RESEARCH QUESTION: Is blastocyst transfer (BT) associated with a higher offspring secondary sex ratio and monozygotic twinning (MZT)? DESIGN: A systematic search of PubMed/MEDLINE, Embase, Web of Science, Cochrane Library and Google Scholar databases was carried out for studies published between 1995 and May 2017 using relevant keywords and a meta-analysis performed on selected studies. The analysis was performed using Stata 12.0; odds ratios (OR) and 95% confidence intervals (CI) were used to assess the results for binary studies. Subgroup analyses and meta-regression were also conducted. RESULTS: Twenty-six studies published between 2001 and May 2017 (sex ratio: 13, MZT: 12, and both sex ratio and MZT: 1) were identified. The analysis showed a significantly higher M/F ratio at birth (OR = 0.89, 95% CI: 0.86 to 0.93, I2 = 19.8%) and a higher risk of MZT (OR = 0.37, 95% CI: 0.22 to 0.60, I2 = 75.2%) after BT compared with cleavage-stage embryo transfer (CT). Furthermore, a subgroup analysis was performed based on studies published after 2009; results were found to be consistent with the 2009 meta-analysis. CONCLUSIONS: This meta-analysis provides an update and stronger evidence to support the observation that BT is associated with a higher proportion of males and an increased risk of MZT. In clinical practice, these BT-associated neonatal outcomes should be taken into account when counselling infertility patients.

The risk of birth defects among children born after vitrified blastocyst transfers and those born after fresh and vitrified cleavage-stage embryo transfers.

PURPOSE: To explore the risk of birth defects among children born after vitrified blastocyst transfers and those born after fresh and vitrified cleavage-stage embryo transfers. METHODS: A retrospective cohort study was conducted including infants born after fresh and vitrified day 3 embryo transfers and those born after vitrified day 5 or 6 blastocyst transfers from January 2005 through December 2016. The outcome measures included any birth defect, multiple birth defects and 13 individual categories of birth defects. RESULTS: Any birth defect occurred in 1.15% of infants born after fresh day 3 embryo transfers, 1.75% of infants born after vitrified day 3 embryo transfers, 1.60% of infants born after vitrified day 5 blastocyst transfers and 1.10% of infants born after vitrified day 6 blastocyst transfers. There was no difference in the risk of birth defects between vitrified blastocyst-stage transfers and vitrified cleavage-stage transfers (including day 5 vs. day 3 and day 6 vs. day 3) among all births or in only singletons or twins. For infants born after cleavage-stage embryo transfers at day 3, there was no difference in the risk of birth defects between fresh embryo transfers and vitrified embryo transfers among all births or in only singletons or twins. CONCLUSIONS: Transfer of vitrified day 5 or 6 blastocysts does not increase the risk of birth defects compared with vitrified day 3 embryos. However, randomized control trials and follow-up studies of the long-term outcome of children born after blastocyst-stage transfers are needed to confirm the clinical safety of extending embryo culture to the blastocyst stage.

Dichorionic triplets following frozen-thawed poor-stage embryo transfer: a report of two cases and a review.

BACKGROUND: We describe two cases of dichorionic triplet pregnancy after a frozen-thawed poor-stage embryo transfer. A 39-year-old and a 41-year-old woman underwent ART treatment. The first patient underwent intracytoplasmic sperm injection (ICSI) at 34 years of age, and two frozen-thawed poor-stage embryos were transferred at 39 years of age with assisted hatching, resulting in a trichorionic triamniotic triplet pregnancy. The second patient underwent ICSI, and two poor-grade blastocysts were transferred followed by assisted hatching, resulting in a dichorionic triamniotic triplet pregnancy. In the first case, the heartbeat of one monozygotic twin fetus had stopped on day 48 post-transfer (9 weeks 2 days), resulting in a dichorionic diamniotic twin pregnancy. A healthy boy and girl were delivered by elective caesarean section at 36 weeks, 5-days gestation. In the second case, the patient underwent selective reduction of the monochorionic twins, resulting in a single pregnancy that was vaginally delivered without any problems at 38 weeks 0-days gestation. SHORT CONCLUSIONS: Numerous factors may be associated with the development of a monochorionic pregnancy; however, controversies still remain. The present morphological grading for embryos is insufficient for inhibiting the development of a monochorionic pregnancy.

Comparative neonatal outcomes in singleton births from blastocyst transfers or cleavage-stage embryo transfers: a systematic review and meta-analysis.

BACKGROUND: Comparative neonatal outcomes with respect to singleton births from blastocyst transfers or cleavage-state embryo transfers are controversial with respect to which method is superior. Many studies have yielded contradictory results. We performed a systematic review and meta-analysis for the purpose of comparing neonatal outcomes in single births following IVF/ICSI. METHODS: We searched the Medline, Embase and Cochrane Central Register of Clinical Trials (CCTR) databases until October 2016. Studies and trials that contained neonatal outcomes for singleton births were included. Data were extracted in 2 × 2 tables. The analysis was performed using Rev Man 5.1 software. Risk ratios (RRs) and risk differences, with 95% confidence intervals, were calculated to assess the results of each outcome. Subgroups were applied in all outcomes. Newcastle-Ottawa scale (NOS) checklists were used to assess the quality of the referenced studies. RESULTS: Twelve studies met the criteria in this meta-analysis. There was a high risk of preterm birth after blastocyst embryo transfer versus the risk after cleavage-stage transfer (RR: 1.11, 95% CI: 1.01-1.22). For the "only fresh" subgroup, the outcome was coincident (RR: 1.16, 95% CI: 1.06-1.27). For the "fresh and frozen" and "only frozen" subgroups, there were no differences. Patients who received fresh blastocyst embryo transfers had a high risk of very preterm births (RR: 1.16, 95% CI: 1.02-1.31). Finally, cleavage-stage embryo transfers were associated with a high risk of infants who were small for gestational age (0.83, 95% CI: 0.76-0.92) and a low risk of those who were large for gestation age (1.14, 95% CI: 1.04-1.25). CONCLUSIONS: The risks of preterm and very preterm births increased after fresh blastocyst transfers versus the risks after fresh cleavage-stage embryo transfers. However, in frozen embryo transfers, there were no differences. Blastocyst embryo transfers resulted in high risks of infants who were large for gestational age, and cleavage-stage embryo transfers resulted in high risks of infants who were small for gestational age.

Reproductive outcomes of retransferring retained embryos in blastocyst transfer cycles.

OBJECTIVE: To determine the incidence of embryo retention (ER) in the transfer catheter following embryo transfer (ET) in blastocyst transfer and investigate whether retransferring retained embryos has an impact on reproductive outcomes in patients undergoing in vitro fertilization-ET. METHODS: We retrospectively analyzed the records of 1,131 blastocyst transfers, which comprised 223 single blastocyst transfer (SBT) and 908 double blastocyst transfer (DBT) cycles. Each SBT and DBT group was classified depending on whether ET was performed without retained embryos in the catheter during the first attempt (without-ER group) or whether any retained embryos were found following ET (ER group) for the purpose of comparing reproductive outcomes in a homogenous population. RESULTS: The overall incidence of finding retained embryos was 2.8% (32/1,131). There were no retained embryos in SBT cycles. In DBT cycles, implantation rates (30.0% vs. 26.6%), positive ß-hCG rates (57.2% vs. 56.2%), clinical pregnancy rates (45.3% vs. 46.9%), and live birth rates (38.9% vs. 43.8%) were not significantly different between the without-ER and ER groups. There were no significant differences in the mean birth weight (g) 2,928.4±631.8 vs. 2,948.7±497.8 and the mean gestational age at birth (269.3±17.2 days vs. 264.2±25.7 days). A total of nine cases of congenital birth defects were found in this study population. Eight were observed in the without-ER group and one in the ER group. CONCLUSION: Our results suggest that retransfer of retained embryos does not have any adverse impact on reproductive outcomes in blastocyst transfer cycles. Furthermore, our results support finding that SBT might be advantageous for decreasing the incidence of retained embryos in catheters.

Reproductive outcomes of retransferring retained embryos in blastocyst transfer cycles / 대한생식의학회지

OBJECTIVE: To determine the incidence of embryo retention (ER) in the transfer catheter following embryo transfer (ET) in blastocyst transfer and investigate whether retransferring retained embryos has an impact on reproductive outcomes in patients undergoing in vitro fertilization-ET. METHODS: We retrospectively analyzed the records of 1,131 blastocyst transfers, which comprised 223 single blastocyst transfer (SBT) and 908 double blastocyst transfer (DBT) cycles. Each SBT and DBT group was classified depending on whether ET was performed without retained embryos in the catheter during the first attempt (without-ER group) or whether any retained embryos were found following ET (ER group) for the purpose of comparing reproductive outcomes in a homogenous population. RESULTS: The overall incidence of finding retained embryos was 2.8% (32/1,131). There were no retained embryos in SBT cycles. In DBT cycles, implantation rates (30.0% vs. 26.6%), positive β-hCG rates (57.2% vs. 56.2%), clinical pregnancy rates (45.3% vs. 46.9%), and live birth rates (38.9% vs. 43.8%) were not significantly different between the without-ER and ER groups. There were no significant differences in the mean birth weight (g) 2,928.4±631.8 vs. 2,948.7±497.8 and the mean gestational age at birth (269.3±17.2 days vs. 264.2±25.7 days). A total of nine cases of congenital birth defects were found in this study population. Eight were observed in the without-ER group and one in the ER group. CONCLUSION: Our results suggest that retransfer of retained embryos does not have any adverse impact on reproductive outcomes in blastocyst transfer cycles. Furthermore, our results support finding that SBT might be advantageous for decreasing the incidence of retained embryos in catheters.

Elective single embryo transfer: Comparison of blastocyst and cleavage-stage embryo transfer.

Objective: Blastocysts are reportedly suitable for preventing multiple pregnancies as a result of the high implantation rate per embryo. The present study compared clinical results for elective single embryo transfer (ET) between blastocysts and cleavage-stage embryos in order to ascertain the usefulness of blastocyst culturing in single ET. Methods: Between January 2002 and December 2004, conventional in vitro fertilization ET and/or intracytoplasmic sperm injection was carried out for single ET in 86 cycles, to prevent multiple pregnancies (for medical reasons or because of patient wishes). Results: Among the 80 cycles in which a fresh embryo was transferred, pregnancy/implantation rates per ET were 35.3% for day 2/3 ET and 50.0% for day 5 ET, and pregnancy/implantation rates per oocyte retrieval were 35.3% for day 2/3 ET and 44.2% for day 5 ET. Ongoing pregnancy/delivery rates per oocyte retrieval were 32.4% for day 2/3 ET and 38.5% for day 5 ET. Monozygotic twinning occurred in one case of day 5 ET. Conclusions: Pregnancy rates per single ET tended to be higher for day 5 ET than for day 2/3 ET. However, no marked differences were identified in ongoing pregnancy/delivery rates per oocyte retrieval between groups. (Reprod Med Biol 2005; 4: 197-201).