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At least 19 recordsLinked to original sources
PubMed2001

Cryopreservation of embryos, blastocysts, and pregnancy rates of blastocysts derived from frozen-thawed embryos and frozen-thawed blastocysts.

PURPOSE: To evaluate the development of cryopreserved embryos when thawed and subsequently cultured to the blastocyst stage in comparison to transferring cryopreserved blastocysts. METHODS: In this retrospective clinical study, we have evaluated 170 cycles in patients undergoing IVF treatment for infertility. Cryopreserved embryos were thawed and were subsequently cultured and transferred at the blastocyst stage. Cryopreserved blastocysts (Day 6) were thawed and transferred immediately. RESULTS: Five hundred and sixty embryos and 444 blastocysts have been thawed. In the embryos group, the survival rate was 89% while in the blastocyst group the survival rate was 56%. In the embryos group the blastocyst development rate was 24.5%. The implantation rate in the embryos group was 20.6% per group blastocyst transferred compared to 5.3% in the blastocyst group. CONCLUSIONS: The ability of cryopreserved embryos to develop to blastocysts and their implantation potential does not seem to be greatly affected by the cryopreservation procedure.

Blastocyst↗
PubMed2001

Ultrastructural observations of enzymatically treated human blastocysts: zona-free blastocyst transfer and rescue of blastocysts with hatching difficulties.

Enzymatic treatment of the zona pellucida to either soften or remove totally the zona before blastocyst transfer has resulted in high implantation rates. The zona is usually completely dissolved after 1.5 min exposure with 10 IU pronase at 37 degrees C. Since there may be concerns that pronase treatment for periods of 1.5 min or longer may cause adverse effects on the trophectoderm (TE) and inner cell mass (ICM), the changes to human blastocysts exposed to different time intervals of pronase were investigated. Of 18 blastocysts exposed to pronase for 1.5 min, the zona was completely dissolved and no changes were observed by light microscopy (LM) or transmission electron microscopy (TEM), compared with 11 naturally hatched untreated blastocysts (controls). In another five blastocysts exposed to pronase for 2 min, no LM changes were observed but subtle TEM changes such as fewer bundles of tonofibrils attached to desmosomes were observed. When three other blastocysts were exposed to pronase for 5 min, the blastocoele collapsed, and the TE cells started to show blebbing under LM. Under TEM, the cytoplasm of TE cells was extensively vacuolated and many TE cells showed cytoplasmic blebbing towards the blastocoele. However, the epithelium was uninterrupted with intact tight junctions and desmosomes. Of a separate group of 44 blastocysts cultured in vitro, 54.5% had hatching difficulties when monitored from day 5 to day 8 and 80% of these could be rescued by removal of the zona with pronase for 1.5 min prior to extensive degeneration taking place. The results confirm that the optimal time for softening or complete removal of the zona before transfer was around 1.5 min and that enzymatic treatment was a safe, non-invasive procedure to remove the zona of blastocysts. The human embryonic TE is a very hardy, robust epithelium that withstands pronase treatment.

Adult↗
PubMed2005

Microsuction of blastocoelic fluid before vitrification increased survival and pregnancy of mouse expanded blastocysts, but pretreatment with the cytoskeletal stabilizer did not increase blastocyst survival.

OBJECTIVE: To ascertain effects of thermal change, size of blastocoele, artificial shrinkage, and cytoskeletal stabilizer on survival of blastocysts from vitrification. DESIGN: In vitro and in vivo study. SETTING: University infertility clinic and academic research laboratory. ANIMAL(S): Female mice of outbred ICR strain, aged 6 to 8 weeks. INTERVENTION(S): In experiment 1, various stages of mouse blastocysts were vitrified by using conventional straws or closed pulled straws (CPS). In experiment 2, microsuction was performed of blastocoelic fluid for blastocysts and expanded blastocysts before vitrification. In experiment 3, cytochalasin B (CCB) was used to treat embryos during vitrification. In experiment 4, vitrified expanded blastocysts were transferred to pseudopregnant mice. MAIN OUTCOME MEASURE(S): Survival and pregnancy. RESULT(S): The survival rates of early blastocysts were high and not different between the conventional straws and the CPS. The survival rates decreased for blastocysts and expanded blastocysts in both of the two methods. But the use of CPS achieved higher survival rates for blastocysts (83% vs. 70%) and expanded blastocysts (60% vs. 39%) than did the conventional straws. Microsuction before vitrification increased the survival rates for blastocysts (92% vs. 80%) and expanded blastocysts (89% vs. 59%). Survival of vitrified embryos was not distinct between CCB treatment and non-CCB treatment. The percentage of live young from vitrified expanded blastocysts using microsuction was greater than that from vitrified expanded blastocysts without microsuction (34% vs. 9%). CONCLUSION(S): The size of the blastocoeles influenced survival of blastocysts from vitrification. A rapid thermal change of CPS and effective reduction of blastocoelic fluid by microsuction may facilitate vitrification and reduce ice crystal damage for blastocysts and expanded blastocysts. The microfilament inhibitor of CCB treatment did not increase their survival rates.

Animals↗
PubMed1999

Heparin-binding EGF-like growth factor interacts with mouse blastocysts independently of ErbB1: a possible role for heparan sulfate proteoglycans and ErbB4 in blastocyst implantation.

Blastocyst implantation requires molecular and cellular interactions between the uterine luminal epithelium and blastocyst trophectoderm. We have previously shown that heparin-binding EGF-like growth factor (HB-EGF) is induced in the mouse luminal epithelium solely at the site of blastocyst apposition at 16:00 hours on day 4 of pregnancy prior to the attachment reaction (22:00-23:00 hours), and that HB-EGF promotes blastocyst growth, zona-hatching and trophoblast outgrowth. To delineate which EGF receptors participate in blastocyst activation, the toxicity of chimeric toxins composed of HB-EGF or TGF-(&agr;) coupled to Pseudomonas exotoxin (PE) were used as measures of receptor expression. TGF-(&agr;) or HB-EGF binds to EGF-receptor (ErbB1), while HB-EGF, in addition, binds to ErbB4. The results indicate that ErbB1 is inefficient in mediating TGF-(&agr;)-PE or HB-EGF-PE toxicity as follows: (i) TGF-(&agr;)-PE was relatively inferior in killing blastocysts, 100-fold less than HB-EGF-PE, (ii) analysis of blastocysts isolated from cross-bred egfr+/- mice demonstrated that HB-EGF-PE, but not TGF-(&agr;)-PE, killed egfr-/- blastocysts, and (iii) blastocysts that survived TGF-(&agr;)-PE were nevertheless killed by HB-EGF-PE. HB-EGF-PE toxicity was partially mediated by cell surface heparan sulfate proteoglycans (HSPG), since a peptide corresponding to the heparin-binding domain of HB-EGF as well as heparitinase treatment protected the blastocysts from the toxic effects of HB-EGF-PE by about 40%. ErbB4 is a candidate for being an HB-EGF-responsive receptor since RT-PCR analysis demonstrated that day 4 mouse blastocysts express two different erbB4 isoforms and immunostaining with anti-ErbB4 antibodies confirmed that ErbB4 protein is expressed at the apical surface of the trophectoderm cells. It is concluded that (i) HB-EGF interacts with the blastocyst cell surface via high-affinity receptors other than ErbB1, (ii) the HB-EGF interaction with high-affinity blastocysts receptors is regulated by heparan sulfate, and (iii) ErbB4 is a candidate for being a high-affinity receptor for HB-EGF on the surface of implantation-competent blastocysts.

ADP Ribose Transferases↗
PubMed2003

A morphological and chromosomal study of blastocysts developing from morphologically suboptimal human pre-embryos compared with control blastocysts.

BACKGROUND: IVF laboratories performing embryo transfer at day 2 or 3 after fertilization are currently discarding pre-embryos considered suboptimal using morphological criteria. The objective of this study was to investigate whether blastocysts, cultured from such pre-embryos (surplus), were chromosomally and morphologically normal. As a control group we used morphologically good quality embryos (GQE), cultured to the blastocyst stage. METHODS: Human pre-embryos considered suboptimal were cultured to the blastocyst stage. As a control group, frozen-thawed pre-embryos of good quality were cultured under identical conditions. The chromosomal status of the blastocysts obtained was studied by multi-colour fluorescence in-situ hybridization for chromosomes 13, 16, 18, 21, 22, X and Y. RESULTS: There is, on average, a significantly higher degree of chromosomal aberrations in blastocysts derived from surplus pre-embryos compared to blastocysts derived from GQE, and the chromosomal aberrations are generally found in a higher number of blastomeres per blastocyst. In addition, blastocysts from surplus pre-embryos had significantly poorer morphology compared to GQE. Improvement in morphology and/or developmental rate in surplus pre-embryos between day 2 and day 3 did not predict a morphologically/chromosomally normal blastocyst. However, this study shows that close to half of the surplus pre-embryos that reach the blastocyst stage can be considered chromosomally normal when assessed for these seven chromosomes. Furthermore, we found that chromosomal aberrations were more concentrated in a particular cell population within blastocysts derived from GQE, compared with surplus blastocysts. CONCLUSIONS: The study suggests that even if the IVF laboratory is on average making the correct decision about the potential of a pre-embryo, surplus pre-embryos that might become chromosomally normal blastocysts are still being discarded.

Adult↗
PubMed2000

Predictive value of 72-hour blastomere cell number on blastocyst development and success of subsequent transfer based on the degree of blastocyst development.

OBJECTIVE: To determine the predictive value of 72-hour blastomere cell number on blastocyst development and to compare success rates of subsequent transfer based on the degree of blastocyst development. DESIGN: Retrospective clinical study. SETTING: Private assisted reproductive technology center. PATIENT(S): Ninety-three women aged 32.0 +/- 5.1 years undergoing oocyte retrieval for IVF. INTERVENTION(S): Bipronucleate oocytes obtained from IVF were grown for up to 168 hours after fertilization and subsequently transferred at the blastocyst stage. MAIN OUTCOME MEASURE(S): Percentages of embryos developing to blastocyst from 72-hour embryos by blastomere cell number and subsequent implantation and pregnancy rates of transferred blastocysts. RESULT(S): Rates of blastocyst formation and expansion increased as cell numbers at 72 hours increased. Implantation rates were 43% for embryos transferred to women receiving only expanded blastocysts and 17% for embryos transferred to women receiving one or more less developed blastocysts. Pregnancy rates were higher for women receiving only expanded blastocysts than for women receiving one or more less developed blastocysts, although the difference was not significant. CONCLUSION(S): More developed 72-hour embryos are more likely to become blastocysts and expand. Implantation rates are greater for the transfer of expanded rather than unexpanded blastocysts.

Adult↗
PubMed2003

Outcome of blastocyst transfer according to availability of excess blastocysts suitable for cryopreservation.

The purpose of this study was to assess the outcome of blastocyst transfer in relation to the presence or absence of excess blastocysts available for cryopreservation. The study was designed as a retrospective case series in a tertiary care private hospital. The study group consisted of 450 blastocyst stage embryo transfer cycles. In 139 cycles there were excess freezeable blastocysts (group 1), in 78 cycles there were excess but unfreezeable blastocysts (group 2), and in 233 cycles there were no excess blastocysts (group 3). A mean of three blastocysts was replaced in all groups. Treatment cycle characteristics, implantation and pregnancy rates following fresh and cryopreserved blastocyst transfer were assessed in each group. More embryos reached the blastocyst stage in group 1 and more blastocysts were of good quality. In group 1, clinical pregnancy and implantation rates (71 and 41%) were significantly higher compared with groups 2 (56 and 27%) and 3 (43 and 19%). Embryos that were selected for transfer among a cohort of good quality blastocysts yielded the highest implantation and pregnancy rates. Given a clinical pregnancy rate of 71%, an implantation rate per embryo of 41%, and a multiple pregnancy rate of 58%, serious consideration should be given to a single blastocyst transfer in these patients.

Abortion, Spontaneous↗
PubMed2001

Ultrastructure of bovine blastocysts following cryopreservation: effect of method of blastocyst production.

The objective of this study was to describe the ultrastructure of blastocysts derived by in vivo and in vitro methods and to investigate how the morphology is affected by exposure to cryoprotectant (10% glycerol) or cryopreservation by conventional slow freezing. In vivo derived blastocysts were characterized by a narrow perivitelline space (PvS), a continuous cover of numerous stacked microvilli (MV) on the plasma membrane, a well-defined system of cell-to-cell coupling and a large population of round or elongated mitochondria with numerous transverse cristae. Exposure of these blastocysts to cryoprotectant was manifested by shrinkage of the blastocysts and swelling of the mitochondria. Cryopreservation resulted in further shrinkage, damage to the MV, and accumulation of cellular debris. In comparison, the in vitro matured (IVM)/in vitro fertilized (IVF) in vivo cultured blastocysts displayed a wider PvS; they appeared to possess less MV and all blastocysts displayed some cellular debris in their PvS. There was also a decrease in the number of junctional contacts between the trophoblastic cells. The reaction of these blastocysts to exposure to cryoprotectant was similar to that of the in vivo derived blastocysts. However, they appeared to be more susceptible to cryopreservation. The totally in vitro produced (IVP) blastocysts displayed a wider PvS, no stacking of the MV, increased numbers of lipid droplets and a further reduction in the junctional contacts between trophoblastic cells. The IVP blastocysts sustained breakage of the zona pellucida on exposure to cryoprotectant and were extremely sensitive to cryopreservation, losing all cell structure and organization. The findings of the present study indicate that in vivo derived blastocysts possess certain structural characteristics that confer a greater tolerance on them to exposure to cryoprotectant and cryopreservation.

Animals↗
PubMed2002

Consequences of bovine oocyte maturation, fertilization or early embryo development in vitro versus in vivo: implications for blastocyst yield and blastocyst quality.

The aim of this study is to examine the effect of bovine oocyte maturation, fertilization or culture in vivo or in vitro on the proportion of oocytes reaching the blastocyst stage, and on blastocyst quality as measured by survival following vitrification. In Experiment 1, 4 groups of oocytes were used: (1) immature oocytes from 2-6 mm follicles; (2) immature oocytes from > 6 mm follicles; (3) immature oocytes recovered in vivo just before the LH surge; and (4) in vivo matured oocytes. Significantly more blastocysts developed from oocytes matured in vivo than those recovered just before the LH surge or than oocytes from 2-6 mm follicles. Results from > 6 mm follicles were intermediate. All blastocysts had low survival following vitrification. In Experiment 2, in vivo matured oocytes were either (1) fertilized in vitro or (2) fertilized in vivo by artificial insemination and the resulting presumptive zygotes recovered on day 1. Both groups were then cultured in vitro. In vivo fertilized oocytes had a significantly higher blastocyst yield than those fertilized in vitro. Blastocyst quality was similar between the groups. Both groups had low survival following vitrification. In Experiment 3a, presumptive zygotes produced by in vitro maturation (IVM)/fertilization (IVF) were cultured either in vitro in synthetic oviduct fluid, or in vivo in the ewe oviduct. In Experiment 3b, in vivo matured/in vivo fertilized zygotes were either surgically recovered on day 1 and cultured in vitro in synthetic oviduct fluid, or were nonsurgically recovered on day 7. There was no difference in blastocyst yields between groups of zygotes originating from the same source (in vivo or in vitro fertilization) irrespective of whether culture took place in vivo or in vitro. However, there was a dramatic effect on blastocyst quality with those blastocysts produced following in vivo culture surviving vitrification at significantly higher rates than their in vitro cultured counterparts. Collectively, these results indicate that the intrinsic quality of the oocyte is the main factor affecting blastocyst yields, while the conditions of embryo culture have a crucial role in determining blastocyst quality.

Animals↗
PubMed1999

Two-blastocyst transfer has similar pregnancy rates and a decreased multiple gestation rate compared with three-blastocyst transfer.

OBJECTIVE: To examine the effect of the number of blastocysts transferred on pregnancy and multiple gestation rates. DESIGN: Retrospective study. SETTING: Academic infertility center. PATIENT(S): Patients < 40 years undergoing IVF, with FSH levels of < 15 mIU/mL and more than three eight-cell embryos. INTERVENTION(S): Embryos were cultured in P1 until day 3 and then transferred to blastocyst medium. A maximum of three blastocysts were transferred. MAIN OUTCOME MEASURE(S): Pregnancy, multiple gestation, and implantation rates. RESULT(S): All 55 patients developed blastocysts and underwent ET. Twenty-four patients had three embryos transferred and 29 patients had two embryos transferred. Two patients had only one embryo each for transfer. There was no difference in the viable pregnancy rate between the two-blastocyst transfer and three-blastocyst transfer groups (62% vs. 58%). In the two-blastocyst transfer group, 39% of pregnancies were multiple gestations (all twin gestations), compared with 79% of pregnancies in the three-blastocyst transfer group (50% twin gestations, 29% triplet gestations). The implantation rate was 47% in both groups. CONCLUSION(S): A commercially available, sequential culture system is highly effective for producing viable blastocysts. Two-blastocyst transfer eliminated the risk of triplets while maintaining the same high success rates seen with three-blastocyst ET.

Adult↗
PubMed2000

Blastocyst quality affects the success of blastocyst-stage embryo transfer.

OBJECTIVE: To determine the relationship between blastocyst quality and the results of embryo transfer at the blastocyst stage. DESIGN: Retrospective case analysis. SETTING: Tertiary care private hospital IVF center. PATIENT(S): A total of 350 blastocyst-stage embryo transfer cycles. INTERVENTION(S): In vitro culture to the blastocyst stage was undertaken in 350 ICSI cycles where four or more cleavage-stage embryos were available on day 3. MAIN OUTCOME MEASURE(S): Relationship between blastocyst quality and implantation and clinical and multiple pregnancy rates. RESULT(S): Transfer of at least one grade 1 or grade 2 blastocyst or one hatching blastocyst was associated with very high implantation and pregnancy rates. However, transfer of grade 3 blastocysts yielded very low implantation and pregnancy rates. CONCLUSION(S): There appears to be a strong correlation between blastocyst quality and success of blastocyst transfer.

Blastocyst↗
PubMed2003

Vitrification of zona-free rabbit expanded or hatching blastocysts: a possible model for human blastocysts.

BACKGROUND: The purpose of this study was to test the effectiveness of one two-step (A) and two one-step (B1 and B2) vitrification procedures on denuded expanded or hatching rabbit blastocysts held in standard sealed plastic straws as a possible model for human blastocysts. The effect of blastocyst size was also studied on the basis of three size categories (I: diameter <200 micro m; II: diameter 200-299 micro m; III: diameter >/==" BORDER="0">300 micro m). METHODS: Rabbit expanded or hatching blastocysts were vitrified at day 4 or 5. Before vitrification, the zona pellucida was removed using acidic phosphate buffered saline. For the two-step procedure, prior to vitrification, blastocysts were pre- equilibrated in a solution containing 10% dimethyl sulphoxide (DMSO) and 10% ethylene glycol (EG) for 1 min. Different final vitrification solutions were compared: 20% DMSO and 20% EG with (A and B1) or without (B2) 0.5 mol/l sucrose. RESULTS: Of 198 vitrified blastocysts, 181 (91%) survived, regardless of the vitrification procedure applied. Vitrification procedure A showed significantly higher re-expansion (88%), attachment (86%) and trophectoderm outgrowth (80%) rates than the two one-step vitrification procedures, B1 and B2 (46 and 21%, 20 and 33%, and 18 and 23%, respectively). After warming, blastocysts of greater size (II and III) showed significantly higher attachment (54 and 64%) and trophectoderm outgrowth (44 and 58%) rates than smaller blastocysts (I, attachment: 29%; trophectoderm outgrowth: 25%). CONCLUSIONS: These result demonstrate that denuded expanded or hatching rabbit blastocysts of greater size can be satisfactorily vitrified by use of a two-step procedure. The similarity of vitrification solutions used in humans could make it feasible to test such a procedure on human denuded blastocysts of different sizes.

Animals↗
PubMed2000

Blastocyst score affects implantation and pregnancy outcome: towards a single blastocyst transfer.

OBJECTIVE: To determine the relationship between blastocyst score and pregnancy outcome. DESIGN: Retrospective review of blastocyst transfer in an IVF clinic. SETTING: Private assisted reproductive technology unit. PATIENT(S): 107 patients undergoing blastocyst culture and transfer of two embryos. INTERVENTION(S): Culture of all pronucleate embryos in sequential media to the blastocyst stage (day 5), followed by transfer of two blastocysts. MAIN OUTCOME MEASURE(S): Implantation rates, pregnancy rates, and twinning were analyzed. RESULT(S): When a patient received two top-scoring blastocysts (64% of patients), implantation and pregnancy rates were 70% and 87%, respectively. The twinning rate in this group was 61%. When only one top-quality blastocyst was available for transfer (21% of patients), the implantation and pregnancy rates were 50% and 70%. The twinning rate for this group was 50%. In contrast, when only low-scoring blastocysts were available for transfer (15% of patients), implantation and pregnancy rates were 28% and 44%, and the twinning rate was 29%. No monozygotic twins were observed in this group of patients. CONCLUSION(S): The ability to transfer one high-scoring blastocyst should lead to pregnancy rates greater than 60%, without the complication of twins.

Adult↗
PubMed1998

High implantation and pregnancy rates with transfer of human blastocysts developed in preimplantation stage one and blastocyst media.

OBJECTIVE: To evaluate the proficiency of preimplantation stage one (P1) and blastocyst media in supporting human blastocyst development and to document implantation and clinical pregnancy rates from the transfer of the normally developed blastocysts. DESIGN: Retrospective clinical study. SETTING: Private IVF unit of a university-affiliated center. PATIENT(S): Twenty-eight women aged 33.7 +/- 2.9 years who underwent IVF treatment for infertility. INTERVENTION(S): Bipronucleate oocytes obtained from IVF and intracytoplasmic sperm injection were cultured in vitro with P1 and blastocyst media for 96-120 hours. One to three embryos were transferred (2.1 +/- 0.2 for the patients who became pregnant and 1.5 +/- 0.3 for those who did not become pregnant). MAIN OUTCOME MEASURE(S): Total number and percentage of developed blastocysts, frequency of blastocysts of grades A and B, and implantation and pregnancy rates. RESULT(S): From 431 oocytes retrieved, 269 bipronucleate oocytes were cultured, producing 81 blastocysts that resulted in the transfer of 54 embryos in 27 procedures. Blastocysts developed in 39.7% +/- 5.5% of the pregnant group and 30.2% +/- 4.5% of the nonpregnant group. From 15 (15/27 = 55.6%) clinical pregnancies, 18 (18/54 = 33.3%) gestational sacs were visualized. The rate of implantation in the pregnant group was 58.1% (18/31). CONCLUSION(S): These results provide evidence for the benefits of extending human embryo culture with P1 and blastocyst media for all normally fertilized embryos in vitro.

Adult↗
PubMed1987

Accumulation of oestrone by pig blastocysts and its potential physiological significance for blastocyst development in vitro.

Oestrone accumulation of Day-5 pig blastocysts and the potential physiological significance of oestrone and oestradiol-17 beta for blastocyst development were investigated in vitro. After 6 h of in-vitro culture in medium supplemented with 10 nM-[3H]oestrone, the accumulation amounted to 550 +/- 49 d.p.m. (s.e.m.) per 10 blastocysts. The accumulation of [3H]oestrone (or its metabolite(s] was reduced (P less than 0.001) in the presence of a 100-fold excess of unlabelled oestrone or oestradiol-17 beta to 135 +/- 14 d.p.m. or 148 +/- 28 d.p.m. per 10 blastocysts, respectively. The accumulation of [3H]oestrone was not affected in the presence of a 100-fold excess of unlabelled progesterone, testosterone or oestrone sulphate. When blastocysts were post-incubated for 30 or 60 min in [3H]oestrone-free medium, blastocysts retained 74.1 +/- 16.8% and 66.0 +/- 10.4%, respectively of their initial radioactivity. In parallel experiments with [3H]progesterone the respective values were 23.8 +/- 3.0% and 21.7 +/- 2.1%. The presence of the antioestrogen nafoxidine (15 micrograms/ml) in basic culture medium impaired (P less than 0.001) the transformation of morulae to blastocysts (21.5 +/- 8.9%) compared to controls (98.3 +/- 1.7%). The inhibitory effects could be overcome (P less than 0.001) by a supplementation with 1 nM- or 100 nM-oestradiol-17 beta (62.5 +/- 12.8% and 80.0 +/- 6.2% development to blastocysts) but not with 1 nM- or 100 nM-oestrone (30.3 +/- 9.6% and 45.2 +/- 10.5%). Blastocyst expansion was also decreased P less than 0.01) to 61.0 +/- 11.4% of control values in the presence of 15 micrograms nafoxidine ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

Elective transfer of single fresh blastocysts and later transfer of cryostored blastocysts reduces the twin pregnancy rate and can improve the in vitro fertilization live birth rate in younger women.

OBJECTIVE: To determine the extent to which embryo selection by blastulation and elective single blastocyst transfer, supported by efficient cryostorage of spare embryos, can reduce multiple pregnancies and maintain or improve on the live birth rate from IVF. DESIGN: Prospective, nonrandomized cohort study. SETTING: Sydney IVF, a private clinic in Australia. PATIENT(S): In vitro fertilization patients aged <38 years with three or more usable blastocyst, recruited from April 2000 through December 2001, with pregnancies followed up until August 2004. INTERVENTION(S): Blastocysts were cultured and cryostored with stage-specific culture medium and low oxygen conditions. MAIN OUTCOME MEASURE(S): Fetal heart-positive twin pregnancy rate and accumulating "take-home baby" rate per retrieval leading to blastocyst transfer. RESULT(S): Among 121 women who elected single fresh blastocyst transfer (but who could elect to have two frozen blastocysts transferred at once), 79 (65.3%) took home a baby, with a twin pregnancy rate of 7%. Among 285 women who chose two blastocysts for fresh transfer, 184 (64.2%) took home at least one baby, with a twin pregnancy rate of 34% and five perinatal deaths. CONCLUSION(S): With technically appropriate blastocyst culture and freezing, and elective single blastocyst transfer in the fresh cycle, the overall multiple pregnancy rate can be reduced by >75%, permitting in this series a slight increase in the chance of taking home a baby.

Adult↗
PubMed1975

The implantation chamber, blastocyst and blastocyst imprint of the rat; a scanning electron microscope study.

Splitting the uterus longitudinally through implanatation sites makes it possible to obtain access to blastocysts and implantation chambers during stages of implanatation of the blastocyst in the rat. On the afternoon of day 5 of pregnancy, blastocysts lie in a shallow antimesometrial depression and tend to fall free of the uterus when the chamber is opened. On day 6, blastocysts are oriented in a mesonmetrial-antimesometrial plane, occupy a distinct implantatopm chamber, and tend to adhere to one side or the other of the uterus, leaving an imprint on the contralateral side. After about noon of day 6, some of the blastocysts split in half laterally, and by day 7 all blastocysts which are exposed are split. In addition to demonstrating increased adhesion of blastocyst to uterine epithelium, the procedure clearly shows the progressive elongation of the imlantation chamber. The embrvonic cell mass is specifically oriented on day 6, and is clasped but not distorted, whereas the abembryonic trophoblast is slightly compressed and indented by the uterine epithelium. The microvilli of the uterine epithelium within the imprint become progressively flattened when compared to the microvilli of the implantation chamber outside of the imprint. The method provides a means of gaining direct access to the surface of uterine epithelium precisely where it has been in association with the blastocyst not only for scanning electron microscopy but also for studies of the properties of the surface constituents.

Animals↗
PubMed1975

Mouse embryo development in vitro: effects of inhibitors of RNA and protein synthesis on blastocyst and post-blastocyst embryos.

The effect of inhibitors of RNA synthesis (Cordycepin, Actinomycin D) and protein synthesis (Cycloheximide) on the development and growth of mouse blastocysts in vitro was explored. Blastocysts exposed in vitro for 24 hours to 50 mu-g/ml Cordycepin, 0.005 mu-g/ml Actinomycin D, or 0.1 mu-g/ml Cycloheximde grew and began to attach to the dish in the similar manner as did the controls. Cell number, 3-H-thymidine-labeling index and mitotic index in treated blastocysts were also similar to controls. Cell number, 3-H-thymidine-labeling index and mitotic index in treated blastocysts were also similar to controls. Control blastocysts grown in vitro for six days attached to the dish, trophoblastic layer was spread and inner cell mass continued to grow and formed an egg-cylinder like structure. Blastocysts grown in constant presence of 50 mu-g/ml of Cordycepin in themedium or those exposed to inhibitor only for the first 24 hours failed to develop inner cell mass derivatives in culture, although the growth of trophoblastic cells was as in controls. The same results were obtained if blastocysts were exposed to 0.005 mu-g/ml of Actinomycin D or to 0.1 mu-g/ml of Cycloheximide either continuously or for the first 24 hours. Higher concentrations of Actinomycin D (0.05 mu-g/ml) or Cycloheximde (1 mu-g/ml) were toxic for the blastocysts causing their degeneration within 24-48 hours. Our results suggested that appropriate concentrations of RNA or protein synthesis inhibitors could prevent the development of inner cell mass derivatives with essentially no effect on the development of primary trophoblast. This would indicate that the process of differentiation of inner cell mass cells is much more sensitive to metabolic inhibitors than the differentiation of giant trophoblastic cells.

Animals↗