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PubMed1999

Development and viability of bovine preplacentation embryos treated with swainsonine in vitro.

This study investigated the effects of swainsonine (a locoweed toxin) on bovine preplacentation embryo development using in vitro procedures. We examined and confirmed the viability and developmental potential of swainsonine-treated embryos by transfer to synchronized recipient heifers. Oocytes (n = 6338) were aspirated from ovaries collected from the abattoir and subjected to in vitro maturation (IVM), in vitro fertilization (IVF) and in vitro culture (IVC). Swainsonine was added to IVM, IVF, IVC media spatially and IVM/IVF/IVC continuously, at 0 ng/ml (TRTI, control), 200 ng/ml (TRT2), 400 ng/ml (TRT3), and 800 ng/ml (TRT4). Embryo development was evaluated with respect to oocyte cleavage rate and the rates of morula and blastocyst formation. There was no difference (P > 0.05) among treatments. The average number of nuclei per blastocyst at Day 7.5 of culture (Day 0 = IVF) was 85.9 +/- 4.3 (n = 47) and 89.3 +/- 4.4 (n = 44) for swainsonine-treated embryos (800 ng/ml) and control embryos, respectively. Pregnancy rate as determined by ultrasonography on day 35 to 40 post embryo transfer was 43.8% and 38.3% for swainsonine-treated (800 ng/ml) and control embryos, respectively. Nine (9.4%) healthy calves were delivered from heifers receiving swainsonine-exposed and nine (9.6%) from control embryos. No difference (P > 0.05) was detected in number of calves developing from TRT and control embryos. We conclude that swainsonine does not have an adverse effect on the development and viability of preplacentation bovine embryos.

Animals↗
PubMed2000

Improved development of DNA-injected bovine embryos co-cultured with mouse embryonic fibroblast cells.

The in vitro development of DNA-injected bovine zygotes, produced in vitro, was compared when cultured with or without mouse embryonic fibroblasts (MEF). The in vivo viability of the embryos produced in these in vitro culture systems was assessed by single or double transfer to recipients taken to term. For these experiments, in vitro fertilized oocytes were not injected (Experiment 1) or were injected with pBL1 gene (Experiment 2) and then cultured for 2 days in CR1aa medium supplemented with 3 mg/ml BSA at 38.5 degrees C in a humidified atmosphere of 5% CO(2) in air. Embryos that developed to the 4- to 8-cell stage at the end of this period were randomly assigned to the two cultured systems and cultured for a further 5 days in groups of 10 to 15 embryos in 0.75 ml medium. These two culture systems were CR1aa medium alone or co-culture with MEF in CR1aa medium supplemented with 10% fetal bovine serum (FBS). Every 48 h, 0.5 ml of the medium was replaced with fresh CR1aa medium and at Day 5 of culture, both media were supplemented by the addition of 5.56 mM glucose and 1x GMS-X supplement solutions. Results were assessed as morphological development of the embryos and data were analyzed by Chi-square test or Student's t-test. The development rate of in vitro fertilization (IVF)-derived embryos co-cultured with MEF (24.4%, 49/201) was significantly higher than those cultured alone (14.4%, 28/194; P<0.05) in Experiment 1. There was a similar difference between the treatments in the proportions of embryos which reached the hatching stage or hatched (10.9%, 22/201 vs. 4.1%, 8/194, respectively; P<0.05). DNA-injected embryos co-cultured with MEF (13.7%, 28/205) showed a higher developmental rate than that of the embryos cultured without MEF (6.7%, 13/193; P<0.05) in Experiment 2. Following the transfer to recipients of one or two DNA-injected blastocysts, the pregnancy rates for two culture systems were similar (MEF co-culture 27.4%, 23/84; CR1aa culture 24. 2%, 16/66). However, the numbers of calves born alive from these pregnancies were higher on the MEF co-culture group (82.6%, 19/23) than the CR1aa culture group (56.2%, 9/16). It was concluded that in vitro embryo development to the blastocyst stage and subsequent in vivo development to term of DNA-injected bovine embryos was improved in comparison to culture in CR1aa alone when the last 5 days of in vitro culture were in a MEF co-culture system.

Animals↗
PubMed1998

Effects of low chronic ethanol exposure on prostaglandin E synthesis by preimplantation mouse embryos.

Embryo prostaglandin (PG) synthesis plays a role in the modulation of embryo metabolism and viability, and in the beginning of the implantation. The effects of ethanol consumption seem to be mediated at least in part by PGs. Increased PG production of postimplantation embryos is associated with retardation and abnormalities in the gestational period. The aim of this study was to find out the effects of low chronic ethanol ingestion by mice, previous to pregnancy, on the PGE released by in vitro and in vivo derived embryos. Immature females or adult males were treated with 5% ethanol for 30 days. After fertilization and mating, two-cell embryos, morulae and blastocysts were collected. The PGE synthesis and release were measured by radioimmunoassay. PGE production by in vitro derived two-cell embryos from ethanol-treated females was lower than in the control group (P < 0.01). Also, PGE production was reduced when two-cell embryos came from ethanol-treated males (P < 0.01). There were no differences in PGE synthesis by in vitro derived morulae and blastocysts in these groups. Two-cell embryos derived from mating produced lower quantities of PGE when they came from ethanol-treated females mated with control males, as compared to the control group. PGE release by in vivo derived blastocysts from ethanol-treated females was reduced significantly, as compared to the control group (P < 0.01). We conclude that a low concentration of ethanol administered chronically to immature females reduces PGE synthesis and release by two-cell embryos from culture in vitro, and by embryos of days 2 and 4 from in vivo development.

Animals↗
PubMed2006

Effect of embryo developmental stage and culture conditions on number and quality of ovine in vitro produced blastocysts.

This study evaluated the final output and quality of in vitro produced blastocysts derived from in vivo recovered sheep embryos cultured at various early developmental stages to blastocyst. A total of 270 embryos were recovered from the oviduct, at different days of the early luteal phase, and were classified into three different developmental stages: 2- to 4-cell (n = 93); 5- to 8-cell (n = 92) and 9- to 12-cell (n = 85). The effect of culture conditions was studied, at the same time, by randomly allocating the embryos to one of four groups: three groups of culture with fresh oviduct monolayers (2, 4 and 5 days old) and a fourth group with 2-day monolayers derived from frozen-thawed oviduct cells. Two control groups were established: first, embryos cultured in semi-defined medium (n = 29) and, second, blastocysts obtained in vivo and cryopreserved (n = 43). Influence on blastocyst yield of embryo developmental stage at the start of culture was statistically significant (p < 0.001). Two- to four-cell embryos showed a significantly lower developmental rate (67.7%) than the 5- to 8-cell (83.6%; p < 0.001) and 9- to 12-cell groups (90.5%; p < 0.0001) and lower quality in terms of blastocyst cryotolerance (56.0 vs. 83.7%; p < 0.005). There were no detected effects relating to the age or handling of the monolayer on the embryo developmental rate, but the day of blastocyst appearance was different between embryos cultured on monolayers derived from fresh or frozen-thawed cells (p < 0.0001); the main influence was on the group of 9- to 12-cell embryos (p < 0.0001). Current results confirm the temporal sensitivities of sheep embryos to in vitro culture, regardless of the culture conditions.

Animals↗
PubMed2000

Pre-persons, commodities or cyborgs: the legal construction and representation of the embryo.

This paper explores how embryos have been represented in law. It argues that two main models have underpinned legal discourse concerning the embryo. One discourse, which has become increasingly prevalent, views embryos as legal subjects or persons. Such representations are facilitated by technological developments such as ultrasound imaging. In addition to influencing Parliamentary debate prior to the passage of the Human Fertilisation and Embryology Act 1990, images of embryos as persons feature prominently in popular culture, including advertising and films, and this discourse came to the fore in the 'orphaned embryo' debate in 1996. The main opposing discourse dismisses embryos as commodifiable objects, which fits with a trend towards legal recognition that reproductive materials such as sperm may be classified as property which may be donated or sold. In the case of cryopreserved embryos these competing perspectives have resulted in litigation over the status of frozen embryos. In this paper I argue that it might be productive to shift the debate from this polarised dispute over whether embryos matter or not, whether they are pre-persons or commodities. Instead, I suggest that we should attempt to locate them in a biotechnological milieu, where cyborg metaphors may be utilised, and questions of how we should treat embryos would be contextualized alongside our response to other cyborgs.

Attitude to Health↗
PubMedDate not supplied

Human pregnancy following cryopreservation, thawing and transfer of an eight-cell embryo.

The widespread use of clomiphene citrate and exogenous gonadotrophins for in vitro fertilization (IVF) in human frequently results in the production of multiple embryos. Replacement of more than two embryos increases pregnancy rate but may result in multiple pregnancies with increased pre- and post-natal abnormality. Preservation of embryos for a limited time allows fewer embryos to be replaced on several different occasions and thus the problems of multiple pregnancy can be minimized, the effectiveness of a single IVF procedure increased and embryo replacement in adverse maternal conditions avoided. Preimplantation embryos have been successfully cryopreserved in many animal species. The sensitivity of embryos to cooling and freezing varies between species and stages of embryo development. We report here the cryopreservation procedures that allow a high survival rate of four- and eight-cell human embryos and the establishment of a pregnancy following the freezing and storage of an eight-cell embryo for 4 months in liquid nitrogen. The pregnancy terminated at 24 weeks' gestation due to development of a septic Streptomyces agalactiae chorion amnionitis after premature membrane rupture.

Bacterial Infections↗
PubMed1991

Characterization of cell-free protein-synthesis systems from undeveloped and developing Artemia embryos.

We have developed and characterized translationally active cell-free systems from Artemia embryos at different developmental times. The optimized lysates from 16 h-developed embryos incorporated radiolabelled amino acids into polypeptides for up to 120 min. The polypeptides synthesized ranged in Mr from 150,000 to 10,000, suggesting that the endogenous mRNA was capable of directing the synthesis of complete polypeptides. Similar results were obtained by using lysates from early developmental stages; even the cell-free system prepared from 1 h-developed embryos was partially active in protein synthesis. Furthermore, all these lysates were capable of re-initiation, as demonstrated by inhibition of initiation with the inhibitors edeine and 7-methylguanosine 5'-triphosphate. Because we found no endogenous protein-synthetic activity in the corresponding lysates from undeveloped embryos, we have used cell-free translation systems from 0 h- and 16 h-developed Artemia embryos to analyse the mechanisms limiting protein synthesis at very early developmental stages. Undeveloped-embryo lysates supplemented with nuclease-treated reticulocyte lysate were capable of translating endogenous mRNAs to give products with a wide spectrum of Mr values, but lysates of 16 h-developed embryos supplemented in this way were not further stimulated. The nuclease-treated lysate appeared to be unnecessary 5 h after resumption of development. These results suggested that a component(s) limiting translation in the undeveloped-embryo lysate was provided by the nuclease-treated reticulocyte lysate, and that this component(s) no longer limited protein synthesis after development. In view of these results, partially fractionated reticulocyte lysates were tested for restoration of protein-synthetic activity in the undeveloped embryo lysate. A high-salt ribosomal wash devoid of ribosomal subunits, which is considered a crude polypeptide-initiation-factor preparation, also restored translation activity in the undeveloped embryo lysate and made it capable of directing the synthesis of both endogenous mRNAs and exogenous (globin) mRNA.

Animals↗
PubMed1990

Impaired peripheral T3 production but normal induced thyroid hormone secretion in the sex-linked dwarf chick embryo.

Plasma concentrations of thyroxine (T4), triiodothyronine (T3) and chicken GH (cGH), together with hepatic 5'-monodeiodination (5'-D) activity, were measured in normal (Dw) and dwarf chick (dw) embryos at incubation d 18. An injection of 10 micrograms of ovine GH (oGH) raised plasma concentrations of T3 in Dw embryos after 1 and 2 h and stimulated hepatic 5'-D activity after 2 h. A non-specific increase in T4 was also observed after 1 h in Dw animals probably due to the heterologous nature of the injection. These effects were not observed in dw embryos. An injection of 1 microgram of TRH was able to increase cGH levels after 15 min in Dw embryos, whereas the the observed increase in the dw group was not significant. In Dw embryos, 0.01, 0.1 and 1 microgram of TRH increased plasma concentrations of T3 in a dose-dependent way, whereas in dw embryos, no reaction to the TRH injections was seen, except for the highest dose used. Contrary to this observation, T4 was increased to the same level in both Dw and dw embryos following TRH injections. An injection of 1 microgram of ovine CRH increased corticosterone after 0.5 h and elevated T3 and T4 after 2 h to the same extent in Dw and dw embryos. It is concluded that the thyrotrophic activities of TRH and oCRH and the corticotropic activity of oCRH do not differ between normal and sex-linked dwarf embryos. However TRH and GH were unable to stimulate the T4-T3 conversion in the liver of dw embryos, presumably due to the lack of hepatic GH receptors in these animals.

Animals↗
PubMed1991

[Rate of early abortion after in vitro fertilization and embryo transfer].

The high rate of implantation failures in infertile patients after in vitro fertilization must be regarded as the major problem of the kind of treatment. Usually, no information on the development of the embryo can be obtained for the time between embryo replacement and rising beta-hCG levels. Own studies on the early pregnancy factor (EPF) showed a positive reaction few hours following the contact of a fertilized oocyte with the endometrial surface. Therefore, we used the EPF as a marker for the viability of the embryo in 82 patients after in vitro fertilization and embryo transfer. Within two days after embryo transfer the EPF was positive in 52 (63%) patients and negative in 30 (37%) patients. In these women the embryos may have been lost during handling or may have discontinued further development. Between day 3 and day 12 after transfer the EPF turned to negative values in 35 patients--especially between day 6 and 10. These cases must be regarded as true implantation failures. After day 12 following embryo transfer, rising beta-hCG levels could be measured in 17 women (21%), but only in 12 patients (15%) could a growing embryonic sac be detected by ultrasound. From these figures, we may conclude, that about half of the embryos are lost already during the step of embryo transfer and the other half during implantation. Therefore, more attention should be given to the handling of the embryos to increase the pregnancy rate after in vitro fertilization.

Abortion, Spontaneous↗
PubMed1990

[Effect of sequential embryo transfer on pregnancy following in vitro fertilization].

In this study, the influence of sequential embryo transfers in an in-vitro fertilisation programme was examined. After in-vitro fertilisation, a maximum of 6 fertilised oocytes were cultured. In cases with more than 6 fertilised oocytes, the rest was cryopreserved in the pronucleus stage. At day 2 after an oocytes retrieval, three embryos with the best morphological appearance were replaced and the remaining embryos (1-3) were cultured for further 3 days. At day 5 after oocytes collection, second a embryo transfer was performed, if one of these embryos had reached the blastocyst stage. In a total of 106 patients, 40 pregnancies (38%) could be observed. No statistical difference in the pregnancy rate could be seen between the group with a second embryo transfer (n = 38; 42%) and the group without second transfer (n = 68; 35%). The incidence of multiple pregnancy was not statistically different between both group and no high-rank multiple pregnancy (greater than Triplete) were observed. Out of 300 cultured embryos, only 59 embryos (17%) reached the blastocyst stage. In the group, in which a second embryo transfer was performed, 22 patients received one blastocyst and 13 patients two blastocysts during the second transfer. The second transfer did not have a significant effect on the pregnancy rate in this series. The most important factor for the induction of pregnancy seems to be the quality of the embryos transferred on day 2 following oocyte retrieval.

Embryo Transfer↗
PubMed2000

Diminished PGE2 content, enhanced PGE2 release and defects in 3H-PGE2 transport in embryos from overtly diabetic rats.

Diminished PGE2 levels in diabetic embryos are related to the development of malformations, and thus the aim of the present study was to determine whether PGE2 levels are modified in rat embryos cultured in diabetic serum during organogenesis, and if PGE2 content and release, and 3H-PGE2 uptake and release, are altered in incubated diabetic embryos. Rats were made diabetic by steptozotocin (60 mg kg(-1)) before mating. Control rat embryos cultured for 24 h (explantation Day 9) in the presence of diabetic serum showed diminished PGE2 levels. When Day 10 diabetic embryos were incubated, embryo PGE2 levels were lower, but the PGE2 released to the incubation media was much higher than in controls. Uptake of 3H-PGE2 by diabetic embryos was initially enhanced (5-10 min), then reached similar levels to controls (20-100 min). Release of 3H-PGE2 previously incorporated during a 60-min incubation was greater in diabetic embryos than in controls. These results show diminished PGE2 content in both diabetic and normal embryos cultured in the presence of diabetic serum, but suggest that diabetic embryos have the capability to produce and release high levels of PGE2. The enhanced release of PGE2 is probably the result of transport abnormalities, and leads to the elevated PGE2 concentrations found in the incubating medium and to the diminished intraembryonic PGE2 levels that alter embryonic development.

Animals↗
PubMed2004

Single embryo transfer in clinical practice.

The high incidence of multiple pregnancies is the main reason for adverse treatment outcome in assisted reproduction. A good strategy to avoid multiple pregnancies is elective single embryo transfer and cryopreservation of spare embryos. Important factors in an elective single embryo transfer programme are good counselling of the patients and the selection of embryos with high implantation potential. In the infertility clinic at Helsinki University Central Hospital the elective single embryo transfer programme was started in 1997 and in 2000 the transfer policy turned to single embryo transfer as primary option. In 2003 60% of fresh transfers were elective single embryo transfers and 66% of frozen transfers were single embryo transfers. It has been shown that an elective single embryo transfer programme can be adopted in daily practice and that it decreases the multiple pregnancy rate, in our programme to around 7% with acceptable overall pregnancy and delivery rates. In Finland the increased use of single embryo transfer has reduced the proportion of multiple births. Finally, a good cryopreservation programme is essential to achieve a good cumulative delivery rate without multiple pregnancies.

Cryopreservation↗
PubMed2005

Analysis of mRNA transcripts for insulin-like growth factor receptors and binding proteins in bovine embryos derived from somatic cell nuclear transfer.

The low efficiency of animal production using somatic cell nuclear transfer procedures is considered to be the result of an incomplete reprogramming of donor cell nucleus, which leads to abnormal expression of developmentally important genes. The objective of this study was to determine the abundance of gene transcripts of insulin-like growth factor (IGF)-related genes in cloned bovine embryos reconstructed with somatic cells. Single embryos derived from nuclear transfer reconstructed with somatic cells (NT-SC) or embryo blastomeres (NTEM), in vitro fertilization (IVF), in vivo production (Vivo), and parthenogenetic treatment (PA) were analyzed. The relative abundance of mRNA was examined by real-time PCR. Transcripts of the IGF-1 receptor (r) and IGF binding protein (BP)-2 were detected in all embryos, regardless of origin. IGF-IIr and IGFBP-3 transcripts signals in NT-SC embryos were detected with significantly lower frequencies of 25 and 50%, respectively. Although IGF-Ir and IGFIIr transcript levels were not significantly different in NT-SC, NT-EM, IVF, Vivo, and PA embryos, the relative abundance in individual embryos indicated large variation in NT-SC. IGFBP-2 and IGFBP-3 levels were high in the Vivo embryos compared with NT-SC, NT-EM, IVF, or PA embryos. These results suggest differences in levels of transcripts of IGF-related genes in the bovine embryos produced by NT compared with IVF, Vivo, and PA.

Animals↗
PubMed1997

The role of the number of replaced embryos on intracytoplasmic sperm injection outcome in women over the age of 40.

In order to examine if the transfer of more than three embryos has any beneficial effect on the outcome of intracytoplasmic sperm injection (ICSI) cycles in women aged > 40 years, a retrospective analysis was made of all the ICSI cycles which were performed in this age group from 1 October 1991 to 31 December 1995. A total of 525 cycles was performed in 321 patients. In 413 cycles, at least one normally fertilized embryo was available for transfer. In 271 cycles, one to three embryos were replaced while in the remaining 142 cycles at least four embryos were replaced. There was no difference in implantation rate (number of gestational sacs/number of embryos transferred), after the transfer of one to three embryos (5.2%), compared with the transfer of at least four embryos (5.1%). The pregnancy rate/embryo transfer and the clinical pregnancy rate/embryo transfer were, however, higher when at least four embryos were replaced than was the case with one to three embryos (27.5 versus 11.8%, P < 0.0001 and 20.42 versus 9.96%, P < 0.005, respectively). There were no statistically significant differences in the delivery rates, multiple pregnancy rates or spontaneous abortion rates. The pregnancy rate and the clinical pregnancy rate after ICSI in women > or = 40 years of age are related to the number of embryos replaced.

Adult↗
PubMed1997

Multiple attempts at embryo transfer: does this affect in-vitro fertilization treatment outcome?

In this study, we retrospectively analysed data from 877 patients who had 1204 embryo transfer procedures following in-vitro fertilization (IVF) at Midland Fertility Services, UK, between January 1991 and December 1995 to investigate the factors contributing to failure of embryo transfer at first attempt and the impact of immediate retransfer of retained embryos on the treatment outcome. Embryos were significantly more likely to be retained when the embryo transfer catheter was contaminated with mucus (3.3 versus 17.8%, P = 0.000001) or blood (3.3 versus 12%, P = 0.00001) and when the transfer procedure was difficult compared with when it was easy (20.3 versus 0.8%, P = 0.00001). There was no significant difference in the clinical pregnancy rate between those who had all their embryos transferred at the first attempt (24.7%) and those who required more than one attempt (23.2%). The types of embryo transfer catheter used in the unit did not show any difference in terms of embryo retention. Although we recommend aspiration of cervical mucus in order to reduce the rate of retained embryos, there is no evidence from our study to suggest that pregnancy rate is compromised when embryos are retained, provided they are discovered and immediately retransferred into the uterine cavity. Immediate retransfer is more convenient to the patients and reduces the laboratory workload without compromising the treatment outcome.

Adult↗
PubMed1998

Intracellular pH of the mouse preimplantation embryo: amino acids act as buffers of intracellular pH.

The inclusion of specific amino acids in conventional culture media has been shown to enhance mammalian embryo development in vitro. Amino acids have been shown to confer their benefits to the preimplantation embryo in a number of different ways. However, their ability to buffer intracellular pH (pHi) has not been investigated. Thus, the aim of this study was to determine if amino acids regulate pHi in the mouse preimplantation embryo. pHi was determined using carboxy-seminaphthorhodafluor-1 (SNARF-1) and confocal microscopy. Incubation with 5,5-dimethyl-2,4-oxazol-idinedione (DMO), a non-metabolizable weak acid, resulted in a significant intracellular acidification in the zygote, 2-, 4- and 8-16-cell embryo. However, in the presence of groups of amino acids, the degree of acidification due to DMO was markedly reduced in the mouse embryo up to the 4-cell stage. Specifically, non-essential amino acids and glutamine had the greatest capacity to buffer pHi in the early embryo. The ability of amino acids to buffer pHi was not apparent from the 8-16-cell stage onwards. In contrast to the precompacted embryo, the morula did not undergo a significant decrease in pHi until exposed to DMO concentrations > or = 10 mM in the absence of amino acids. This may be due to the generation of a permeability seal during compaction, thus enabling the morula to regulate its own pHi. This regulatory ability could either be reversed by causing the morula to decompact, or created by inducing premature compaction in the 8-16-cell embryo. Data presented in this study indicate that amino acids act as buffers of pHi in the early embryo and play a key role in regulating cell physiology. Further evidence for this was provided by the result that only those embryos cultured in 30 mM DMO in the presence of non-essential amino acids and 1 mM glutamine did not block at the 2-cell stage, but grew on to develop into expanded blastocysts.

Amino Acids↗
PubMed1998

Ultrasound tracking of the movement of embryo-associated air bubbles on standing after transfer.

The aim of this study was to investigate whether standing upright shortly after embryo transfer has any potential to affect the position of embryos transferred to the uterine cavity during treatment with in-vitro fertilization (IVF). This was assessed by ultrasound-guided tracking of embryo-associated air within the uterine cavity. A prospective study of 93 patients undergoing 101 consecutive embryo transfers in an IVF programme was carried out. Transvaginal ultrasound guided embryo transfer was performed with a second ultrasound in standing position immediately after transfer, allowing the movement of embryo-associated air to be assessed. No movement occurred in 94.1% (95/101) of transfers, movement of <1 cm in 4.0% (4/101) of transfers and movement of 1-5 cm in 2.0% (2/101) transfers. No movement of embryo-associated air out of the uterine cavity, either into the cervix or the intramural portion of the Fallopian tube, was seen. Standing shortly after embryo transfer does not play a significant role in the final position of embryo-associated air and is unlikely to be a factor in determining the position of embryos transferred to the uterine cavity during treatment with IVF.

Air↗
PubMed1999

Transfer technique and catheter choice influence the incidence of transcervical embryo expulsion and the outcome of IVF.

We examined the influence of the procedures used in embryo transfer on pregnancy rates. Over a period of 15 months (Nov. 1996-Jan. 1998), 320 patients were recruited. They were randomized on an alternate basis either to a Wallace catheter or an Erlangen metal catheter. Randomization was also applied within the same groups for embryo transfer at 48 h and 72 h post-insemination. Fifty patients randomly selected from each group were subjected to speculum examination 15 min following embryo transfer, during which any fluid leaking from the cervix was examined for the presence of embryos. In five patients a transvaginal-transmyometrial transfer was performed. The pregnancy rate appeared to be slightly higher in patients who had their embryos transferred at 72 h than in those patients who had their transfers at 48 h, but this difference was not significant in either group. (The ease with which the Erlangen catheter was used compared with that of the Wallace catheter was reflected in a significantly lower incidence of uterine sounding of cervical dilatation and bleeding.) Also there was a significant increase (P = 0.0001) in the mucus attached to the tip of the Wallace catheter and the embryos trapped compared with those of the Erlangen group (P = 0.0007). The pregnancy rate per embryo transfer was apparently higher in the Erlangen group than in the Wallace group but this difference was not significant. In eight (16%) patients of the Wallace group, 1-3 embryos were found in the fluid sucked from the external os, compared with three (6%) patients in the Erlangen group, but again this difference was not significant. In 92% of patients who became pregnant, the transfer procedure was smooth and easy. Successful embryo transfer was not influenced by the time of transfer post-insemination. The choice of catheter did not affect pregnancy rate. In cases in which transcervical transfer is very difficult or impossible, transvaginal-transmyometrial transfer is a viable option. The significance of early or late expulsion of transferred embryos into the vagina needs to be addressed in larger controlled studies.

Adult↗