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At least 937 records · Page 52Linked to original sources
PubMed1998

Production of sheep embryos in vitro and development of progeny following single and twin embryo transfers.

An in vitro culture system for producing ovine embryos is described, in which heat inactivated sheep serum was used as a protein source for maturation, fertilization and 7-d culture phases. Ovaries obtained from a commercial abattoir were used as the source of mature ewe (285) and lamb oocytes (356), which were subsequently cultured in this system to yield similar mean cleavage rates of 91 and 92%, respectively, but significantly different (P < 0.025) proportions for blastocysts/cleaved oocytes (46 and 18%). At Days 7 or 8 of culture, embryos from each source were transferred, either singly (ewe-derived) or in pairs (ewe- and lamb-derived), to hormonally synchronized recipient ewes, resulting in the birth of lambs ranging in weight from 2.5 to 8.8 kg for singletons and 2.6 to 8.0 kg for twins. Mean gestation length of 153.4 +/- 0.5 d (range 151 to 160) was slightly longer than the expected norm of about 150 d. The pregnancy rate was significantly higher after the transfer of embryo pairs (64%) than single (39%) embryos, while survival of lambs to weaning was greater for singleton (80%) than for twin lambs (43%). Some factor(s) in the culture media, such as growth factors in the sera, may have a mitogenic effect on embryonic cells, or it may alter the distribution of cells to the trophectoderm and inner cell mass, resulting in enhanced body growth rates.

Animals↗
PubMed1987

Outcome of in-vitro fertilization and embryo transfer after different regimens of ovarian stimulation.

Sixty-eight women with bilateral tubal disease and fertile male partners underwent ovarian stimulation in 187 cycles for IVF after randomization to different ovulation induction regimens. All patients initially received 150 mg clomiphene citrate on days 5-9, this regimen induced sufficient stimulation in a smaller proportion of patients than the two other regimens used subsequently which included clomiphene in combination with human menopausal gonadotrophins (hMG). The fertilization rate was significantly reduced (52.4%) in oocytes collected from cycles stimulated with hMG alone (in a small sub-group of poor responders) compared with a rate of 64.1-66.4% in cycles stimulated with clomiphene alone or in combination with hMG. Embryonic development 44-48 h after insemination was significantly retarded when clomiphene alone was utilized but a higher proportion of fragmented or abnormal embryos was observed after stimulation with hMG alone. In 118 cycles embryo transfer was performed and 20 pregnancies were established, a pregnancy rate of 16.9%. All but two pregnancies were established when two or more embryos were transferred and when the embryos were at the 4-cell or later stage of development. The regimen of clomiphene in combination with 150 i.u. hMG resulted in significantly greater numbers of oocytes recovered and embryos available per patient for transfer than the other two regimens studied.

Chorionic Gonadotropin↗
PubMed1996

The effect of assisted hatching on pregnancy rates after frozen embryo transfer.

OBJECTIVE: To compare clinical pregnancy and implantation rates after transfer of frozen-thawed embryos prepared according to an assisted hatching protocol or a nonassisted hatching protocol. DESIGN: A historical cohort study in which a cohort of patients who underwent an assisted hatching protocol was matched for clinical parameters to an external historical cohort treated before assisted hatching was available. SETTING: In vitro fertilization-ET facility of a university-based practice. PATIENTS: Seventy-nine matched pairs. INTERVENTIONS: Nonassisted hatching patients: embryos were thawed, cultured in human tubal fluid + 0.5% bovine serum albumin until 48 hours and transferred. Assisted hatching patients: embryos thawed, cultured in human tubal fluid + 10% synthetic serum substitute until 72 hours, had assisted hatching and transferred. MAIN OUTCOME MEASURES: Clinical pregnancy (gestational sac) and implantation rates. RESULTS: Twelve (15.2%) clinical pregnancies per transfer in nonhatched group versus 24 (30.4%) in hatched group. Nonhatched group: 284 embryos transferred; 15 (5.3%) implanted. Three pregnancies (25.0%) had two sacs. Hatched embryos: 269 were transferred; 37 (13.7%) implanted. Eleven pregnancies (45.8%) were multiple gestations (9 twins, 2 triplets). CONCLUSION: Clinical pregnancy and implantation rates were higher for group having assisted hatching protocol. It is not clear whether the improvement is due to the overall methodology change or to assisted hatching. Assisted hatching using the zona-drilling technique is not detrimental to frozen-thawed human embryos and may be beneficial.

Adult↗
PubMed2004

Effect of maximal endometrial thickness on outcome after frozen embryo transfer.

The largest study to date on the association of endometrial thickness and subsequent pregnancy rates following frozen embryo transfer with the endometrium prepared by estrogen and progesterone found no improved or adverse outcome if the endometrial thickness was > or = standard deviations above the mean. Neither was there a trend noted for thin endometria.

Embryo Transfer↗
PubMed1991

Survival of bovine embryos transferred to progesterone-treated asynchronous recipients.

Treatment of recipient cows with 100 mg of progesterone daily from Days 1 to 5 of the oestrous cycle increased plasma progesterone compared with vehicle-treated recipients. Embryo transfer to progesterone-treated recipients which showed oestrus 72 h after the donor cows resulted in pregnancy rates at Day 35 similar to those of synchronous (+/- 12 h) recipients (42 vs. 50%). Only 1 of 22 (4.8%) asynchronous (-72 h) vehicle-treated recipients established pregnancy. Similar treatments of cyclic cows with progesterone shortened (P less than 0.01) the interoestrous interval by 3.2 days. When assessed on Day 7 of pregnancy, administration of progesterone to superovulated donor cows on Days 1-4 of pregnancy did not affect early embryo development compared with superovulated cows treated with vehicle alone. Plasma progesterone increased rapidly in superovulated cows compared with cows during the oestrous cycle. The results indicate that administration of progesterone early in the oestrous cycle of the recipient can effectively advance uterine receptivity for the transfer of older asynchronous embryos.

Animals↗
PubMed1987

Follicular fluid contents as predictors of success of in-vitro fertilization-embryo transfer.

In order to establish criteria for selection of the best ova in in-vitro fertilization-embryo transfer (IVF-ET) programes we have examined the follicular fluid (FF) levels of plasminogen activator (PA), collagenolytic activity, progesterone (P) and alpha 2 macroglobulin (alpha 2M) and related them to the success of pregnancy. PA activity was similar in FF of pregnant and nonpregnant cycles, 13.8 +/- 3.9 mU/ml versus 14.6 +/- 2.9 (mean +/- SEM) respectively. By contrast, FF from pregnant cycles exhibited lower collagenolytic activity (49.6 +/- 3.9% versus 67.9 +/- 3.0; P less than 0.001). Likewise, in a semi-quantitative assay of alpha 2M, only 18.4% of the aspirates from pregnant cycles showed a precipitation line, whereas 76.8% of those from non-pregnant cycles were positive. Levels of P in aspirates from pregnant cycles were in the intermediate range, as compared with those from non-pregnant cycles (0.06-5.5 micrograms/ml versus 0.02-12.0 micrograms/ml). All these assays can be completed before ET and performed in IVF-ET programmes. In conclusion, it seems that a combination of follicular alpha 2M levels and collagenolytic activity, and to a lesser extent addition of P assay, may serve as good criteria for selecting the best embryos for establishment of pregnancy.

Cleavage Stage, Ovum↗
PubMed1999

Antiphospholipid antibodies in infertile couples with two consecutive miscarriages after in-vitro fertilization and embryo transfer.

Of 682 women who had undergone in-vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) with embryo transfer, 84 were successful on two occasions, with 16 of these resulting in miscarriage before 20 completed weeks. Antiphospholipid antibodies (APA) were estimated by enzyme-linked immunosorbent assay in these women (group 1) and compared to two control groups: 42 fertile women with three or more miscarriages (group 2) and 60 women with primary infertility undergoing IVF or ICSI (group 3). An apparently higher prevalence of seropositivity was seen in group 1 women (25%) compared to the group 3 women (6.6%) and it was similar to that seen in group 2 women (21.4%). Therefore the recommendation that women with two consecutive miscarriages after IVF or ICSI should have APA estimations performed routinely may be justified.

Abortion, Spontaneous↗
PubMed1984

[Various results of nonsurgical embryo transfer in lactating cattle under field conditions in the Netherlands].

Superovulation was induced in 129 lactating donor cows for embryo transfer under field conditions. Twenty-nine animals (22.5 per cent) responded with fewer than three corpora lutea. The number of animals flushed was ninety-nine, averaging 8.2 corpora lutea per donor cow. The average proportion of recoveries was 56.4 per cent. The quality of the embryos was satisfactory in 64 per cent of the cases. The average number of embryos and egg cells per donor was 4.6, which resulted in 2.9 good quality embryos per donor. The percentage of pregnant recipients was 56 in good quality embryos and 9 for fair quality embryos.

Animals↗
PubMed2003

Serological status and abortion rate in progeny obtained by natural service or embryo transfer from Neospora caninum-seropositive cows.

Bovine neosporosis is an important disease in dairy herds in Argentina. Embryo transfer (ET) technology offers the opportunity to minimize vertical transmission of neosporosis. The objective of this work was to compare the serological status and the incidence of abortion between heifers obtained via natural service and heifers obtained by ET from Neospora-infected cows. Progeny from eight Neospora-infected cows belonging to a commercial dairy farm where ET was routinely performed were studied. Between 1996 and 2001, 16 and 15 heifers were obtained by natural service and ET, respectively. Serostatus and reproductive performance were recorded in both progeny. Serostatus was determined by indirect fluorescent antibody test (IFAT). All heifers obtained by natural service were seropositive and six of 16 pregnancies ended in abortion. All heifers obtained by ET were seronegative and only two abortions of 15 pregnancies were recorded.

Abortion, Veterinary↗
PubMed1992

Influence of number of pre-embryos transferred, progesterone level and oestradiol/progesterone ratio at thaw on pregnancy results during replacement of cryopreserved pre-embryos in natural cycles.

When frozen-thawed pre-embryos were transferred in a natural menstrual cycle, a clinical pregnancy rate of 22% per transfer cycle was obtained. The pregnancy rates were higher when serum progesterone levels at thaw were less than or equal to 3.4 ng/ml than when they were greater than or equal to 3.5 ng/ml. This was reflected in a significantly higher oestradiol/progesterone ratio at thaw in the conception cycles than in the non-conception cycles.

Adult↗
PubMed2005

A preliminary study on reduced dose (33 or 25 microg) gonadotropin-releasing hormone agonist long protocol for multifollicular ovarian stimulation in patients with high basal serum follicle-stimulating hormone levels undergoing in vitro fertilization-embryo transfer.

The aim of the present study was to evaluate the clinical efficacy of half-dose (50 mug) and further reduced dose (33 or 25 mug) gonadotropin-releasing hormone agonist (GnRH-a; triptorelin) long protocols for multifollicular ovarian stimulation (MFOS) for patients with high basal serum follicle-stimulating hormone (FSH) level undergoing in vitro fertilization and embryo transfer (IVF-ET). One hundred and two IVF-ET cycles performed in 84 infertile patients with high basal serum FSH (>10.0 mIU/ml) were included in this retrospective study. Study subjects were assigned to two groups: continuous half-dose GnRH-a long protocol (group A, n = 63) vs. further reduced dose GnRH-a long protocol (group B, n = 39) from half-dose at the start of GnRH-a to one-third or one-quarter dose after pituitary downregulation. Exogenous FSH or human menopausal gonadotropin was administered for MFOS in step-down mode, four or fewer embryos were transferred, and the outcomes of MFOS were compared between the two groups. Serum estradiol (E(2)) level on the day of human chorionic gonadotropin administration was significantly higher in group B (mean +/- standard deviation (SD): 1318.3 +/- 1120.4 vs. 2054.9 +/- 1773.5 pg/ml, p = 0.015). The number of transferable and good-quality embryos was also significantly higher in group B (mean +/- SD: 2.9 +/- 1.7 vs. 3.7 +/- 2.0, p = 0.027; 1.8 +/- 1.4 vs. 2.7 +/- 2.0, p = 0.020). No statistically significant difference in the outcomes was observed with respect to the dose of gonadotropins administered, the number of oocytes retrieved or the clinical pregnancy rate. In conclusion, GnRH-a long protocol with a reduced dose, tapered from the starting half-dose to a third or a quarter of the normal dose after pituitary suppression, may be beneficial for MFOS in IVF-ET patients with a high basal serum FSH level. A further prospective randomized controlled study on a larger scale is needed to confirm these findings.

Adult↗
PubMed1982

Embryo transfer in vivo.

Records of 44 patients with advanced ectopic pregnancy were reviewed. The author demonstrates that in vivo embryo transfer can reimplant later than one week of gestation and that implantation does not require endometrium as the only implantation site. Other tissues and organs can support implantation, but adequate hormonal secretion is necessary.

Diagnosis, Differential↗
PubMed1987

Implications of the placental structure compatibility for interspecies embryo transfer.

Comparative histological features of the chorionic villi in placental cotyledons of the common eland (Taurotragus oryx ) and bongo (Boocercus euryceros ) antelopes and okapi (Okapia johnstoni ) and giraffe (Giraffa camelopardalis ) were examined. The chorionic villi in both antelope species showed only moderate branching and/or surface corrugation and their cross-sections were polygonal to oval. The close similarity in the structure of cotyledons has been apparently a contributing factor for success in mutual interspecies embryo transfer. The chorionic villi in okapi and giraffe had very different structures. In okapi the villi on cross-section were round and filled with thin connective tissue. They showed minimal branching and surface corrugation. In giraffe the villi showed extensive surface corrugation, had multiple fine branches, and were filled with a more dense connective tissue. Prospect for materno-fetal compatibility in mutual embryo transfer between these species is guarded.

Journal Article↗
PubMed1987

Survival of equine embryos transferred to normal and subfertile mares.

To test the hypothesis that an abnormal uterine environment was a cause of early embryonic loss in subfertile mares, morphologically normal embryos were transferred to normal mares (n = 20) and subfertile mares (n = 20), and embryo survival rates were compared. Embryos were recovered nonsurgically at Days 7 to 8 postovulation and transferred surgically to normal and subfertile mares that had ovulated on the same day or within 2 d after a donor. Survival of transferred embryos was monitored by ultrasonography of the recipient mare's uterus from Day 9 through Day 28 postovulation. There were no significant differences (P > 0.5) in the embryo survival rates at Day 12 (11 20 vs 9 20 ) or Day 28 (10 20 vs 8 20 ) for normal or subfertile mares, respectively. The uterine environment of subfertile mares was apparently adequate to support the development of transferred embryos from Days 7 or 8 through Day 28 postovulation.

Journal Article↗
PubMed2000

Day 5 versus day 3 embryo transfer: a controlled randomized trial.

Blastocyst transfer has been suggested to improve implantation rate without affecting pregnancy rate. The aim of this study was to compare the pregnancy and implantation rates of day 3 and 5 transfers in a prospective randomized manner. Patients with four or more zygotes were randomly allocated on day 1 to either day 3 or 5 transfers. Fertilization was achieved through regular IVF or intracytoplasmic sperm injection. Zygotes were kept in Medicult IVF medium for day 3 transfers and transferred into G1.2 and G2.2 on day 1 and 3 respectively for day 5 transfers. The morphologically best two or three embryos or blastocysts were chosen for transfer in both groups. Overall pregnancy rates per embryo transfer were the same (39%) in day 3 and 5 transfers. Implantation rates were 21 and 24% for day 3 and 5 transfers respectively. The pregnancy and implantation rates for day 5 transfers were significantly affected by the availability of at least one blastocyst to transfer and the number of zygotes. The number of good quality embryos on day 3 also significantly affected pregnancy and implantation rates on day 5 transfers. Multiple gestation rate, number of abortions and ongoing pregnancies were similar in both groups. In conclusion, day 3 and 5 transfer had similar pregnancy, implantation and twinning rates. Currently, day 5 transfers have no advantages over day 3 transfers.

Adult↗
PubMed1997

Antenatal detection of Meckel-Grüber syndrome in only one dizygotic twin following in vitro fertilization and embryo transfer.

The first case of Meckel-Grüber syndrome in a dizygotic twin pregnancy following in vitro fertilization and embryo transfer is reported. An ultrasound examination at 26 weeks of gestation revealed multiple malformations of the presenting twin: the combination of an occipital encephalomeningocele, bilateral polycystic kidneys and postaxial polydactyly was suggestive of Meckel-Grüber syndrome. Diagnosis was confirmed after birth. The importance of this case is stressed since particular care must be taken to avoid multiple pregnancies in couples at risk undergoing assisted reproduction.

Diseases in Twins↗
PubMed2005

Impact of a restriction in the number of embryos transferred on the multiple pregnancy rate.

OBJECTIVE: To study the impact of the introduction of reimbursement of in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) laboratory costs in Belgium which is linked to an embryo transfer strategy leading to prevention of multiple pregnancies. The impact on the incidence of multiple and twin pregnancy rate as well as on ongoing pregnancy rate in our centre is calculated. STUDY DESIGN: Observational cohort study of all patients in the first year (July 1, 2003-June 30, 2004) since the implementation of the law and comparison of ongoing pregnancy rate and multiple pregnancy rate of our centre with Belgian data. RESULTS: Our results of one year of IVF/ICSI since reimbursement of laboratory costs show a total conception rate of 42.2% with 29.7% ongoing pregnancies beyond 25 weeks amenorrhea. The multiple pregnancy rate was 8.5% including five monozygotic twin pregnancies. These data show an important decline of multiple pregnancy rate when compared to Belgian data (2002) with 24.4% multiple pregnancy rate in the year prior to reimbursement. CONCLUSION: The introduction of reimbursement of IVF/ICSI laboratory costs coupled to a restriction in the number of embryos for transfer has reached the goal of halving the multiple pregnancy rate since its introduction while maintaining an optimal ongoing pregnancy rate.

Adult↗