Triple Embryo Transfer Research Articles

P-766 Re-assessment of the Belgian legislation on embryo transfer in a blastocyst transfer policy

Abstract Study question How does a multiple fresh blastocyst transfer policy impacts live birth rate (LBR) and multiple live birth rates (MLBR) in relation to maternal age ? Summary answer Fresh transferring of ≥ 2 blastocysts only increases LBR in women above the age of 36 and substantially increases risk of multiples in all age categories. What is known already Multiple pregnancies after ART are recognized as a major complication as it significantly contributes to extreme preterm and very low-birthweight births. Even in the presence of a strict Belgian embryo transfer law in some subgroups in which double embryo transfer (DET) is allowed (women aged <36 years in cycle rank 3 up to 6 and in women aged 36-40 years in cycle rank 2), twining rates remain above 10%. A study by Tannus et al., (2017) concluded that double blastocyst transfer (DBT) is associated with both higher LBR and higher twin birth rates compared to elective single blastocyst transfer (eSBT). Study design, size, duration A single center retrospective, observational cohort study was conducted between July 2010 and December 2020. Both fresh IVF and ICSI cycles were included. A total of 8,402 fresh transfers were performed (2,948 on day 3 and 5,454 on day 5) over the course of the study period. SET was performed in 6,108 cases, DET in 2,077 cases, triple embryo transfer (TET) in 202 cases and multiple embryo transfers (MET) in 15 cases. Participants/materials, setting, methods The primary outcomes of this study were LBR per transfer and twin pregnancy rate. Generalized estimating equations (GEE) with the patient as subject was applied to account for clustering of cycles within women. An interaction analysis between the number of embryos transferred and age categories in the day 5 group was performed. A P-value of < 0.05 was considered statistically significant. Main results and the role of chance In women aged <36 years, chances of a live birth were not significantly higher when two or more vs. a single blastocyst were transferred (OR: 1.014; 95%% CI 0.791 - 1.299; p = 0.91). However, transferring more than one blastocyst in women aged 36-40 years and >40 years did result in a higher chance of live birth compared to SBT (OR: 1.631; 95% CI: 1.218 - 2.185; p = 0.0008 and OR: 1.634; CI: 1.219-2.190; p = 0.0008, respectively).` Women aged 36-40 years and > 40 years had an estimated 19.3% and 66.3% lower odds respectively of a live birth after the transfer of a day 5 embryo, vs. women aged <36 years (OR: 0.800, 95% CI: 0.687-0.931; p = 0.0034 and OR: 0.337, CI: 0.268-0.424; p < 0.0001, respectively). Overall, live births were 28.5% higher when 2 or more blastocysts were transferred compared to an SBT (OR: 1.285 95% CI 1.1.077 – 1.533) (p = 0.0046). The estimated odds for a twin pregnancy were 17.8 times higher for DBT/MBT compared to SBT (OR 17.814; 95% CI: 10.74 - 29.55) (p < 0.0001). Limitations, reasons for caution This study is limited by its retrospective design and no interaction analysis between number of twin pregnancies and age categories was possible due to the low number of twins. Wider implications of the findings The data indicates that in women younger than 36 years only one blastocyst should be transferred regardless the embryo quality or the cycle rank. Only for patients older than 40 years, transfer of two blastocyst(s) could be considered. Trial registration number Not applicable

Single embryo transfer improve the perinatal outcome in singleton pregnancy

Background and objectives: Most of previous studies are comparing the perinatal outcome on singleton babies. There has been no study evaluating the possible effect of singleton embryo transfer on the perinatal outcomes in initial singleton pregnancy resulting from fresh embryo transfer. The purpose of our study is to access the effect of embryo transfer number on obstetric and perinatal risks in order to examine the role of single embryo transfer on perinatal outcomes on initial singleton pregnancy.Materials and methods: This study is a retrospective cohort study and analyzed 6439 fresh embryo transfer women. 1647 initial singleton pregnancy patients were divided into one of the following three groups according to the embryo transfer number: group A (n = 94): single embryo transfer (SET); group B (n = 1321): double embryo transfer (DET); group C (n = 262): triple embryo transfer (TET). The miscarriage rate and the ectopic pregnancy rate was compared between group A and group B, group C. 1273 live birth patients were divided into three groups too. The obstetrics outcomes and perinatal outcomes between group A and group B, group C.Results: There were 94 singleton pregnancy patients in unselective single embryo transfer. Comparing with double embryo transfer, the early miscarriage rate was higher, but late miscarriage rate, ectopic rate, and live birth rate were comparable between two groups. The obstetrics outcomes were comparable between single embryo transfer and other two groups. Although there was no significant difference between group A and other two groups, preterm birth rate, extremely preterm birth rate, low-birth weight rate and very low-birth weight rate increased with the increase of embryo transfer number. The mean delivery weight was highest in singleton babies in single embryo transfer group. It is higher in group A comparing with group B (3440.4 versus 3320.7 g) and comparing with group C (3440.4 versus 3277.4 g).Conclusions: Single embryo transfer was associated with a better perinatal outcome such as preterm birth and low-birth weight in a singleton pregnancy. The mean birth weight was significantly higher in single embryo transfer group too. Single embryo transfer is a reasonable option to reach the goal of in vitro-fertilization – a healthy singleton neonate.

Elective Single Embryo Transfer: Future Forward

Notwithstanding the most noteworthy verifiable live birth achievement rates for couples experiencing in vitro fertilization (IVF), there has been a scourge of iatrogenic twin and higher gestation development considered from this treatment. While some expanded peril is natural for the barren populace requiring treatment, the act of multiple embryo transfer adds to these inconveniences and results, particularly concerning its part in higher number pregnancies. Improvement in cryopreservation procedures has permitted conservation of supernumerary embryos for use in future cycles, and refinements in culture frameworks and embryo selection have brought about the transfer of elective single embryos while keeping up positive pregnancy rates. The willful exchange of a single top notch quality elective single embryo transfer e-SET (Blastocyst) has fundamentally lessened the multiple gestation rates and boosted the rate of singleton pregnancy without compromising the global success rates. We acknowledge that in high-risk situations (e.g. previous history of preterm gestation and poor maternal wellbeing), double-embryo transfer (DET) or triple embryo transfer (TET) ought to be disallowed because of unsuitably high perils. Be that as it may, we contend that ordering e-SET for every single young lady can be viewed as an unsatisfactory break of patient self-governance, particularly since DET/TET offers certain ladies money related and social focal points.

The knowledge of the increased risk of complications in multiple pregnancies does not affect the desire to transfer more than one embryo in in vitro fertilisation treatment.

ObjetiveOne of the main complications in in vitro fertilisation (IVF) is multiple pregnancies. This study was designed to investigate how many embryos subjects participating in an online survey would want to transfer in their IVF cycles.MethodsThis study was conducted in a Brazilian private assisted fertilisation centre. Individuals who accessed the centre’s website were asked to participate in the survey. The survey was based on important information concerning multiple gestations, followed by a single multiple choice question, as follows: ‘Knowing that the transfer of one embryo reduces the chance of pregnancy, and that the transfer of more than one embryo could result in multiple pregnancies, which comes with risks to the mother and the babies, answer: how many embryos would you transfer in your IVF cycle?’. There were three available answers: one, two or three embryos.ResultsA total of 1,049 subjects participated in the survey: 109 males and 940 females. The majority of the participants answered that they would like to have two embryos transferred (53.7%); followed by three embryos (35.0%), and one embryo (11.3%).ConclusionMen and women tend to underestimate the risks of complications associated with multiple embryo transfers and multiple gestations. It is the physician’s responsibility to consider single embryo transfer (SET) as the method of choice and perform double or triple embryo transfers only in special circumstances.

Effect of mood states and infertility stress on patients' attitudes toward embryo transfer and multiple pregnancy

To examine whether mood state or infertility stress influences perceptions of risk, preferences for embryo transfer, or views on multiple pregnancy. Observational cohort study. Hospital-based fertility clinic. One hundred seventy-six women participating in IVF treatment. None. Mood scores, ratings of risk, preference for multiple embryo transfer, and attitudes toward multiple pregnancy. Growing feelings of tension across the cycle corresponded with increases in the perceived riskiness of double-embryo transfer, but there was no change in strength of transfer preferences. Women experiencing negative moods, such as depression, viewed twin and triplet pregnancy as less likely, whereas increasing positive feelings across the cycle were associated with increasing desire for twin pregnancy. Overall, women perceived double- and triple-embryo transfer as less risky by cycle end than at cycle beginning and felt more certain about multiple-embryo transfer. The dyssynchrony observed among changes in mood, perceptions of risk, and transfer preferences challenges assumptions about the way medical risk information influences transfer preferences, and the findings suggest that mood states experienced during an IVF cycle might affect transfer preferences by influencing attitudes toward multiple pregnancy. Additional considerations beyond providing risk information are needed to facilitate effective patient decision making.

Pregnancy and twinning rates using a tailored embryo transfer policy

A tailored embryo transfer policy based on the prognostic profile of the couple was prospectively evaluated. Single-embryo transfer (SET) was performed, followed by double-embryo transfer (DET) in frozen–thawed embryo transfer cycles in women with a good prognosis (<35 years, first cycle, ⩾1 top-quality embryo). DET was performed in both fresh and frozen cycles in women with an intermediate prognosis (<35 years, first cycle and no top-quality embryo available, or <35 years and ⩾1 failed cycles, or 35–38 years). Triple-embryo transfer (TET) in both fresh and frozen cycles was performed in women with a poor prognosis (⩾39 years). The cumulative ongoing pregnancy rate in the cycles of women with a good prognosis was 43% with a multiple pregnancy rate of 2%, in the cycles of women with an intermediate prognosis 27% and 23% and in the cycles of women with a poor prognosis 18% and 13%, respectively. These findings can be used to guide current practice: i.e. performing SET in women with a good prognosis and TET in women with a poor prognosis. The embryo transfer strategy in women with an intermediate prognosis requires further improvement, possibly by refining the prognosis according to the ovarian response after ovarian stimulation.We performed a prospective cohort study evaluating the implementation of the transfer of one embryo in women with a good prognosis, two embryos in women with an intermediate prognosis and three embryos in women with a poor prognosis. In women with a good prognosis (women <35 years, the first cycle and at least one top-quality embryo available), one embryo was transferred followed by two embryos in frozen–thawed embryo transfer cycles. In women with an intermediate prognosis (women <35 years, first cycle and no top-quality embryo, or women <35 years with ⩾1 failed cycle, or women aged 35–38 years), two embryos were transferred in both fresh and frozen–thawed cycles. In women with a poor prognosis (⩾39 years), three embryos were transferred in both fresh and frozen–thawed cycles. In women with a good prognosis, the pregnancy rate after a fresh and subsequent frozen–thawed embryo transfer was 43%, with a multiple pregnancy rate of 2%. In women with an intermediate prognosis, the pregnancy rate was 27%, with a multiple pregnancy rate of 23%. In women with a poor prognosis, the corresponding rates were 18% and 13%. The data in this study can be used to guide current practice, by transferring one embryo in women with a good prognosis and three embryos in women with a poor prognosis. The embryo transfer strategy in women with an intermediate prognosis requires further improvement, possibly by refining the prognosis according to the ovarian response after ovarian stimulation.

Developmental and Genetic Outcomes in Children Conceived Through Assisted Reproductive Technologies

After completing this article, readers should be able to: 1. Describe the outcomes of assisted reproductive technologies (ART) for singleton, twin, and other multiple births. 2. Describe the role of fertility in adverse outcomes seen with ART births. 3. Review the association of birth defects with ART. 4. Delineate the association of disease of genomic imprinting with ART. 5. Describe the relationship between ART and the subsequent incidence of neurodevelopmental sequelae. In the 1977 ruling “Carey v. Population Services International,” the United States Supreme Court ruled that the decision to bear children is constitutionally protected. (1) Significant interest already had been shown in the development and improvements of in vitro fertilization (IVF) for infertile couples. The first human pregnancy and human birth using IVF were reported by Steptoe and Edwards in the United Kingdom. (2) Their work resulted in the first baby born via reproductive technologies, Louise Brown, born on July 25, 1978, at Oldham General Hospital in Oldham, United Kingdom. (3) She was born via a planned cesarean section, and her birthweight was 2.61 kg. The first successful viable IVF in the United States was performed by Jones and Seager-Jones in 1981 in Norfolk, Virginia. (4) Assisted reproductive technologies (ART) have seen a recent surge in popularity. The Centers for Disease Control and Prevention (CDC) reported that 122,872 cycles of ART were initiated in 2003, resulting in the delivery of 48,756 neonates, (5) accounting for approximately 1% of all neonates delivered in the United States. The percentage is higher in many countries, including Denmark, where it is estimated that 5% of all deliveries are with the assistance of ART. (6) Couples pursue ART for myriad reasons, including tubal transport factors, ovulatory dysfunction, uterine factors, endometriosis, male- and female-specific factors, and when a cause of infertility is unknown. (5) It would be very …

Prevention of multiple pregnancies after IVF in women 38 and older: a randomized study

The objective of this study was to answer the question of whether a double instead of triple embryo transfer strategy in patients over 38 years would substantially reduce the number of multiple pregnancies while maintaining the chance of a term live birth at an acceptable level. A randomized controlled two-centre trial was performed. Forty-five patients, 38 years or older, were randomized. Double embryo transfer over a maximum of four cycles (DET group) or triple embryo transfer over a maximum of three cycles (TET group) was performed. The cumulative term live birth rate was 47.3% after four cycles in the DET group and 40.5% after three cycles in the TET group. The difference between the DET and the TET group was 6.8% in favour of the DET group (95% CI −25 to 38). The multiple pregnancy rates in the DET and TET group were 0% (95% CI 0 to 24) and 30% (95% CI 7 to 65) respectively ( P = 0.05). In the DET patients, the mean number of treatment cycles was 2.9 compared with 2.1 in the TET group ( P = 0.01). In women of 38 years and older, double embryo transfer after IVF may result in similar cumulative term live birth rates compared with triple embryo transfer, provided that a higher number of treatment cycles is accepted.

Transfer of nonselected transferable day 3 embryos in low embryo producers

Objective To examine the implantation potential of embryos from assisted reproductive technology cycles with low embryo production and to assess the effects of clinical variables and embryo scores (ES) on pregnancy outcome. Design Prospective clinical study. Setting Assisted reproductive technology unit in a tertiary medical center. Patient(s) From July 1998 to December 2001, 280 cycles in 229 infertile couples produced a limited number of one, two, or three embryos 3 days after oocyte retrieval and underwent fresh embryo transfer (ET). Intervention(s) Embryos with two or more blastomeres were scored and transferred. Main outcome measure(s) ES and implantation rate per ET. Result(s) Of 863 fresh ET cycles during the study period, 32.4% (280) were low embryo producers. Among them, there were no significant differences in average ES of individual embryos in single, dual, or triple ET or in embryos obtained from patients with low or high E 2 responses, or young or old age. Embryos derived from conventional IVF had a better ES than those derived from intracytoplasmic sperm injection. The clinical pregnancy rate was strongly correlated with the cumulative ES. Implantation rates were similar among and between groups, with an average rate of 15.9%. Conclusion(s) Embryos of low embryo producers had an inherently low implantation potential that appeared to be unrelated to the number of embryos transferred, female age, ovarian E 2 genesis, or fertilization method. The cumulative ES can serve as a predictor of pregnancy.

Long-term evaluation of implantation of fresh and cryopreserved human embryos following ovarian stimulation with buserelin acetate-human menopausal gonadotrophin (HMG) or clomiphene citrate-HMG.

This study is a long-term evaluation of the total pregnancy potential of cohorts of fresh and cryopreserved sibling embryos from in-vitro fertilization (IVF) cycles stimulated with either the gonadotrophin-releasing hormone analogue buserelin (BUS) (long protocol) or clomiphene citrate (CC) both in combination with human menopausal gonadotrophin (HMG). Therefore a retrospective analysis was performed on patients who entered the IVF programme between January 1986 and July 1987 and who had triple embryo transfer in the collection cycle. Significantly more fertilized oocytes developed to good-quality embryos in the CC-HMG group (86.1%) than in the BUS-HMG group (80.8%). Transfer of the three morphologically best-looking embryos was performed in day 2 post-insemination in 106 CC-HMG and 80 BUS-HMG cycles. Supernumerary embryos were cultured for a further 24 h and multicellular embryos with up to 20% of fragments were frozen slowly with 1.5 M dimethylsulphoxide on day 3 post-insemination (162 embryos in CC-HMG cycles, 102 embryos in BUS- HMG cycles). Outcome was measured by embryo survival rate, embryo implantation rate and delivery rate in fresh and frozen embryo transfers. Delivery rates were 31.3 and 21.7% per fresh embryo transfer in BUS-HMG and CC- HMG cycles respectively. Fresh embryo implantation rates were significantly higher in collection cycles stimulated with BUS-HMG (17.9%) than in cycles stimulated with CC-HMG (11.3%). Implantation rates were significantly enhanced in embryos transferred in excess of one in cycles leading to pregnancy, perhaps indicative of higher embryo quality in BUS-HMG cycles. Almost all cryopreserved embryos have by now been thawed, so the contribution of frozen embryos to overall pregnancy rates can be evaluated. Overall morphological survival rates of frozen-thawed embryos have by now been thawed, so the contribution of frozen embryos to overall pregnancy rates can be evaluated Overall morphological survival rates of frozen-thawed embryos were similar for 140 embryos from CC-HMG cycles (50%) and 100 embryos from BUS-HMG cycles (46%). The percentage of fully intact embryos was, however, significantly lower in the BUS-HMG group (19%) than in the CC-HMG group (39.5%). Delivery rates were significantly lower following 30 transfers of frozen-thawed embryos from BUS-HMG-stimulated cycles (3.3%) than following 42 transfers of frozen-thawed embryos from CC-HMG cycles (19.1%). Embryo implantation rates were lower for frozen-thawed embryos from BUS-HMG cycles (2.3%) than from CC-HMG cycles (12.7%). Here we demonstrate that ovarian stimulation with the long protocol BUS-HMG instead of the CC-HMG protocol led to higher embryo implantation rates in collection cycles but to lower intact embryo survival rates and to lower embryo implantation rates for frozen sibling embryos. Despite the lower implantation rates with frozen embryos originating from the BUS-HMG protocol, there was no significant difference between total delivery rate per transfer from cycles stimulated with CC-HMG (30.2%) compared with BUS-HMG (33.8%).

Two instead of three embryo transfer in in-vitro fertilization.

The rational of transferring two instead of three embryos was studied through 468 in-vitro fertilization (IVF) treatment cycles in 287 couples. The quality of 1224 embryos was determined according to the fragmentation rate and the morphology as good (A) and poor (B). The influence of the number of embryos transferred (two or three) on the pregnancy rate when the same quality or combinations of good and poor quality embryos transferred was examined. When only good quality embryos were transferred the pregnancy rates in double (AA) and triple (AAA) embryo transfer were 40.5 (17/42) and 42.9% (30/70) respectively (not significant). When only poor quality embryos were transferred, the pregnancy rates in double (BB) and triple (BBB) embryo transfers were 11.0% (11/100) and 22.9% (16/70) respectively (P < 0.001). On the other hand, when good and poor quality embryos were transferred together as AB in double and as AAB and ABB in triple embryo transfer, the pregnancy rates were 36.8 (14/38) and 39.9% (59/148) respectively (not significant). There was no difference in the miscarriage rate between double and triple embryo transfers; 16.7 and 18.1% respectively. The multiple pregnancy rate was 14.3% for double embryo transfers and 32.4% for triple embryo transfers (P < 0.001). This study demonstrates that if there is at least one good quality embryo available for transfer, then double instead of triple embryo transfer will not yield a significantly lower pregnancy rate. The influence of the number of embryos transferred on the pregnancy rate became significant when only poor quality embryos were transferred.(ABSTRACT TRUNCATED AT 250 WORDS)

High Fertilization and Implantation Rates After Intracytoplasmic Sperm Injection

Previously reported better fertilization rate after intracytoplasmic single sperm injection (ICSI) than after subzonal insemination of several spermatozoa was confirmed in a controlled comparison of the two procedures in 11 patients. Intracytoplasmic sperm injection was carried out in 150 consecutive treatment cycles of 150 infertile couples, who had failed to have fertilized oocytes after standard in-vitro fertilization (IVF) procedures or who were not accepted for IVF because not enough motile spermatozoa were present in the ejaculate. A single spermatozoon was injected into the ooplasm of 1409 metaphase II oocytes. Only 117 oocytes (8.3%) were damaged by the procedure and 830 oocytes (64.2% of the successfully injected oocytes) had two distinct pronuclei the morning after the injection procedure. The fertilization rate was not influenced by semen characteristics. After 24 h of further in-vitro culture, 71.2% of these oocytes developed into embryos, which were transferred or cryopreserved. Only 15 patients did not have embryos replaced. Three-quarters of the transfers were triple-embryo transfers. High pregnancy rates were noticed since 67 pregnancies were achieved, of which 53 were clinical, i.e. a total and clinical pregnancy rate of 44.7% and 35.3% per started cycle and 49.6% and 39.2% per embryo transfer. A total of 237 supernumerary embryos were cryopreserved in 71 treatment cycles.

High fertilization and implantation rates after intracytoplasmic sperm injection.

Previously reported better fertilization rate after intracytoplasmic single sperm injection (ICSI) than after subzonal insemination of several spermatozoa was confirmed in a controlled comparison of the two procedures in 11 patients. Intracytoplasmic sperm injection was carried out in 150 consecutive treatment cycles of 150 infertile couples, who had failed to have fertilized oocytes after standard in-vitro fertilization (IVF) procedures or who were not accepted for IVF because not enough motile spermatozoa were present in the ejaculate. A single spermatozoon was injected into the ooplasm of 1409 metaphase II oocytes. Only 117 oocytes (8.3%) were damaged by the procedure and 830 oocytes (64.2% of the successfully injected oocytes) had two distinct pronuclei the morning after the injection procedure. The fertilization rate was not influenced by semen characteristics. After 24 h of further in-vitro culture, 71.2% of these oocytes developed into embryos, which were transferred or cryopreserved. Only 15 patients did not have embryos replaced. Three-quarters of the transfers were triple-embryo transfers. High pregnancy rates were noticed since 67 pregnancies were achieved, of which 53 were clinical, i.e. a total and clinical pregnancy rate of 44.7% and 35.3% per started cycle and 49.6% and 39.2% per embryo transfer. A total of 237 supernumerary embryos were cryopreserved in 71 treatment cycles.

The relationship between embryo quality and the occurrence of multiple pregnancies

To study the relationship between the quality of the transferred embryos and the occurrence of multiple pregnancies. Embryo quality was defined by the cleavage rate and by morphological parameters such as blastomere size and the presence or absence of anucleate fragments.A retrospective analysis of 1,915 consecutive transfers of fresh embryos between January 1986 and December 1989.All the embryo transfers (ETs) were performed in patients from the in vitro fertilization program of the Center for Reproductive Medicine, Vrije Universiteit Brussel, Brussels, Belgium.We confirmed the relationship between the number of embryos transferred and the pregnancy rate (PR): 11.9% of the single, 19.0% of the double, and 34.1% of the triple ETs were successful. Thirty-one percent of these triple embryo replacements resulted in a multiple gestation. At the time of transfer (44 to 48 hours after insemination), we observed that embryos that had undergone at least two mitotic divisions implanted better than two-cell embryos of comparable morphological appearance (implantation rate per transferred embryo: 21.3% versus 12.3%, P less than 0.001) and that heavily fragmented embryos did not implant as well as embryos without or with fewer anucleate fragments (1.5% versus 14.1%, P less than 0.001). The PR, implantation rate, and the incidence of multiple pregnancies increased significantly with the number of good quality embryos that were transferred.Our study indicated that embryo quality based on morphological observations could predict the occurrence of multiple pregnancies.

The relationship between embryo quality and the occurrence of multiple pregnancies

To study the relationship between the quality of the transferred embryos and the occurrence of multiple pregnancies. Embryo quality was defined by the cleavage rate and by morphological parameters such as blastomere size and the presence or absence of anucleate fragments. A retrospective analysis of 1,915 consecutive transfers of fresh embryos between January 1986 and December 1989. All the embryo transfers (ETs) were performed in patients from the in vitro fertilization program of the Center for Reproductive Medicine, Vrije Universiteit Brussel, Brussels, Belgium. We confirmed the relationship between the number of embryos transferred and the pregnancy rate (PR): 11.9% of the single, 19.0% of the double, and 34.1% of the triple ETs were successful. Thirty-one percent of these triple embryo replacements resulted in a multiple gestation. At the time of transfer (44 to 48 hours after insemination), we observed that embryos that had undergone at least two mitotic divisions implanted better than two-cell embryos of comparable morphological appearance (implantation rate per transferred embryo: 21.3% versus 12.3%, P < 0.001) and that heavily fragmented embryos did not implant as well as embryos without or with fewer anucleate fragments (1.5% versus 14.1%, P < 0.001). The PR, implantation rate, and the incidence of multiple pregnancies increased significantly with the number of good quality embryos that were transferred. Our study indicated that embryo quality based on morphological observations could predict the occurrence of multiple pregnancies.

High pregnancy rate after early human embryo freezing

Human embryos produced by in vitro fertilization (IVF) were frozen with 1,2-propanediol as a cryoprotectant. Embryo survival after thawing was related to the presence of a nucleus in frozen cells and decreased with the increasing number of cells in the frozen embryo. None of five embryos frozen 3 or 4 days after IVF survived when thawed. Of 48 early embryos (35 patients) frozen 1 or 2 days after IVF, 42 (87.5%) were transferred in 32 patients. Ten pregnancies were initiated after frozen embryo transfer (ET). If we exclude the three infertile patients who had sexual intercourse in the fertile period, the pregnancy rate for each patient who had 1- or 2-day frozen embryo(s) was 22% (7 of 32). One of the pregnancies was obtained after ET of a 1-cell pronucleated frozen and thawed embryo. The rate of ongoing pregnancies after triple fresh ET was 23%. In patients having four embryos obtained in a single IVF cycle, the expected overall liveborn rate in an IVF-ET program including embryo cryopreservation could theoretically equal that of natural human fertility.

Relationships between embryo transfer results and ovarian response and in vitro fertilization rate: analysis of 186 human pregnancies

We studied the relationships between "pretransfer" parameters (number of follicles, oocytes, and embryos) and the result (occurrence and quality of pregnancy) obtained by transferring one, two, or three embryos. The analysis concerns 186 pregnancies compared with 186 implantation failures. The chances for an oocyte to cleave or for a pregnancy to continue decreased when the number of preovulatory follicles increased. The number of transferred embryos increased with oocyte cleavage rate in nonpregnant patients and in patients with an ongoing pregnancy, but such a relation was not found in the case of failed pregnancy (biochemical pregnancies and abortions). Failed pregnancies occurred in patients who demonstrated the highest oocyte cleavage rate (94.1%), compared with 81.2% for implantation failure and 84.8% for ongoing pregnancy (P less than 0.01). The cleavage rate was also higher in cases of multiple, compared with single, ongoing pregnancies after the transfer of three embryos (79.7% versus 64.5%, P less than 0.001). An important finding was the higher survival rate after triple-embryo transfer in patients, yielding numerous oocytes. The survival rate (fetuses per transferred embryos) after the transfer of three embryos was 14.9% in patients yielding five oocytes, versus 7.7% in patients yielding 3.4 oocytes (P less than 0.05). These results are related to oocyte and embryo viability and uterine ability for pregnancy.