Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Embryos”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,369 records · Page 76Linked to original sources
PubMed1999

Oocyte morphology correlates with embryo quality and pregnancy rate after intracytoplasmic sperm injection.

OBJECTIVE: To evaluate the relation of oocyte morphology with embryo quality and pregnancy rates (PRs) after intracytoplasmic sperm injection (ICSI). DESIGN: Retrospective study of patients undergoing ICSI. SETTING: University Hospital IVF Center. PATIENT(S): Sixty-eight patients who underwent ICSI and had transfer of good-quality embryos (grade 3), 60 patients with transfer of both good- and poor-quality embryos (grade 3 and grade 2), and 18 patients with transfer of poor-quality embryos (grade 2). INTERVENTION(S): Comparison of the outcome of ICSI in the three groups of patients and the relation of oocyte morphology to embryo quality. MAIN OUTCOME MEASURE(S): Oocyte morphology and embryo quality (grade). Fertilization, cleavage, and pregnancy rates. Serum E2 on the day of hCG administration. RESULT(S): Oocytes with poor morphology (dark cytoplasm; many vacuoles or fragments in cytoplasm) led to poor-quality embryos and consequently to lower PRs (5.5% versus 29.4%). Serum E2 on the day of hCG administration was significantly higher in the group with good-quality embryos compared with that with poor-quality embryos (2,047 +/- 135.7 versus 1,651 +/- 164.8 pg/mL, respectively). CONCLUSION(S): Serum E2 on the day of hCG administration is a marker of embryo quality. Oocyte morphology correlates well with embryo quality and PRs after ICSI.

Adult↗
PubMed2003

Surgical recovery and successful surgical transfer of conventionally frozen-thawed embryos in the farmed European polecat (Mustela putorius).

Surgical transfer of in vivo produced conventionally frozen-thawed embryos of farmed European polecat (Mustela putorius) was investigated as a part of an ex-situ preservation program which has the long-term aim of developing a genome resource bank for the endangered European mink (Mustela lutreola). Eighteen oestrous yearling European polecat donors were mated once daily on two consecutive days using 13 fertile males. The donors were surgically flushed for embryos 8-9 days after the first mating. The embryo recovery rate was 60% (116 embryos/193 corpora lutea). The embryos were cryopreserved with 1.5 M ethylene glycol in a programmable freezer using a conventional slow freezing protocol. The thawed embryos were surgically transferred either after dilution with 0.5 M sucrose or directly without removal of ethylene glycol. To induce ovulation, eight recipient females were mated once daily on two consecutive days with vasectomized males starting 7 or 8 days before embryo transfer. The recipients received 7-11 embryos each and three recipients delivered a total of nine pups after a gestation length of 44-46 days. The embryo survival rate was 10% (9 pups/93 frozen embryos). This report describes the first successful cryopreservation of embryos in the Mustelidae family resulting in viable offspring. The low embryo survival rate, however, indicates that the freezing-thawing protocol needs to be improved.

Animals↗
PubMed1999

Factors affecting pregnancy rate following nonsurgical embryo transfer in buffalo (Bubalus bubalis): a retrospective study.

The objectives of this study were to determine the pregnancy rate and factors affecting it following nonsurgical embryo transfer in buffalo. Donor buffalo were superovulated with FSH, and embryos collected nonsurgically were evaluated for stage of development and quality. They were transferred nonsurgically to 91 recipients on Days 5 to 7 of the natural (n = 52) or induced (n = 39) estrus (estrus = Day 0). The overall pregnancy rate of 24/91(26.4%) was higher than in earlier reports for buffalo but was much lower than in cattle. Pregnancy rates were not affected by season (autumn vs winter), side of transfer (right vs left uterine horn), or type of estrus (spontaneous vs induced). The pregnancy rate was high 11/27(40.7%) when donors and recipients were closely synchronized, while it was compromised when recipients were in estrus at +12 h (1/7, 14.3%) and at -12 h (5/27, 18.5%). Asynchrony beyond 12 h on either side resulted into conception failure. The pregnancy rate tended to increase with the increase in CL size of recipients, while stage of embryonic development had no effect. The transfer of an 8-cell embryo with a 16-cell embryo led to the birth of heterosexual twins, indicating that the uterine milieu of Day 5 to 6 recipients may be tolerated by the out-of-phase 8-cell embryo, at least in the presence of a more mature embryo. Embryo quality had the greatest effect on pregnancy rate as it was higher (P < 0.005) after the transfer of Grade I than Grade III embryos (6/10, 60.0% vs 3/36, 13.9%). Assessment of returns to estrus indicated that among nonpregnant recipients, 17/67 (25.4%) embryos never matured sufficiently to prevent luteolysis through maternal recognition of pregnancy (MRP), while 14/67 (20.8%) embryos probably died following MRP. These results indicate that efforts to increase pregnancy rate following embryo transfer in buffalo should include prevention of luteolysis during the first week of transfer and a reduction in the incidence of embryonic mortality.

Animals↗
PubMed1997

The efficacy of trypsin for disinfection of in vitro fertilized bovine embryos exposed to bovine herpesvirus 1.

Bovine cumulus-oocyte complexes (COC) or in vitro fertilized (IVF) embryos were exposed to bovine herpesvirus 1 (BHV-1) during in vitro maturation or co-culture with uterine tubal cells, respectively. Trypsin, at a concentration of 0.25%, was applied (for approximately 90 s) to disinfect either COC or cumulus-free oocytes (CFO) 18 h after insemination, or on day 7 to embryos resulting from infected oocytes. In total, virus was not detected in 71% of 93 samples containing 233 embryos exposed to BHV-1 and trypsin treatment. BHV-1 was detected in 14% and 54% of samples containing a single embryo and five embryos, respectively. In corresponding groups of embryos exposed to BHV-1, then washed but not treated with trypsin (70 samples), 85% and 96% of samples containing one embryo and pooled embryos, respectively, were positive for the virus. There was no effect of trypsin treatment on the development of IVF-embryos. It is concluded that IVF-generated embryos have a greater tendency to carry BHV-1 after experimental exposure to the virus than IVF uterine stage embryos, and that they are more difficult to disinfect by means of the standard trypsin treatment use.

Animals↗
PubMed1996

Early embryonic development and evaluation of equine embryo viability.

Tremendous progress has been made in the development of assisted reproductive techniques that may enhance the reproductive efficiency of the horse. However, techniques that involve the manipulation of oocytes and/or embryos may themselves be detrimental to embryo viability and subsequent development. Therefore, an objective method of assessing viability of embryos before and/or after oocyte/embryo manipulation is desirable. At this time, morphologic evaluation is the most widely used method of determining the viability of equine embryos. Although morphologic assessment of embryo quality will not always accurately predict the survival of individual embryos, it is very useful for predicting the survival of groups of embryos. Other tests that have been used to evaluate equine embryo viability include (1) development during culture in vitro; (2) quantitating metabolism of the fluorescent substrate fluorescein diacetate; (3) quantitating uptake of the fluorescent stain DAPI; and (4) quantitating embryo metabolism. Although these tests offer potential advantages over morphologic assessment alone, their current limitations have prevented their routine use for embryo evaluation. It is likely that as improvements are made in these evaluation methods, they may offer advantages for use alone or in combination to more accurately assess the viability of equine embryos.

Animals↗
PubMed1994

Embryo viability associated with microassisted fertilization.

Embryo morphology and cleavage rates represent useful, but not absolute, measures of embryo viability. Oocyte and embryo chromosomal abnormalities affect embryo viability and are reflected to some degree in the morphology of oocytes and embryos. Microassisted fertilization techniques have been successfully used to treat severe male-factor infertility. Zona drilling using acidified Tyrode's solution is detrimental to oocyte and embryo viability and should not be used. Partial zona dissection (PZD) produces viable embryos that have developmental competence no different from that of routine IVF embryos, but the oocytes should be shrunken in hypertonic sucrose prior to PZD to avoid distortion and mechanical damage. The size of the cut in the zona pellucida is also critical and should be kept to a minimum to avoid loss of blastomeres during transfer. It appears from data on embryo quality, pregnancy rates and implantation rates that SUZI embryos have viability comparable to that of routine IVF embryos. Astonishingly, the passage of an injection needle directly into the ooplasm during ICSI has no effect on fertilization or developmental competence, as demonstrated by the excellent clinical pregnancy rates.

Embryo, Mammalian↗
PubMed2005

Spare embryos: 3000 reasons to rethink the significance of genetic relatedness.

IVF laws in Victoria, Australia provide that human embryos must not remain in storage in excess of 5 years. Studies reviewing the fate of surplus human embryos reveal that close to 90% of couples choose to discard their excess embryos and that hundreds of embryos are disposed of annually. It has been argued that human embryos are a valuable resource and that there is a need to consider educational programmes to encourage couples to donate spare embryos to other infertile couples, rather than discard them. Surveys show that one reason that so few embryos are donated is that couples attach great significance to genetic parenthood. Advances in reproductive technology may necessitate a review of biological definitions of family and the importance of genetic relatedness. It can be argued that it is unreasonable to conclude that genetic ties are so significant that embryos should be discarded rather than donated and raised by non-genetically related parents. It is suggested that education programmes should encourage reflection on people's beliefs about the importance of genetic relatedness with regard to what makes a family. Open embryo donation or directed embryo donation programmes might cause couples to change their minds, or alleviate their anxiety about donating embryos to others.

Attitude↗
PubMed2003

Cryopreserved human embryos in Canada and their availability for research.

OBJECTIVE: To determine the number of cryopreserved human embryos at all Canadian in vitro fertilization (IVF) clinics, the number of these embryos that have been donated to research, and the consent processes regarding the disposition of embryos no longer required for reproductive purposes. METHODS: A questionnaire was mailed to 24 fertility clinics identified as conducting IVF and cryopreservation, inviting completion of the questionnaire by telephone. Thirteen clinics (response rate 54%) completed the survey. RESULTS: As of August 2003, all 13 clinics cryopreserve embryos not required for intrauterine transfer; in total, 15,615 embryos are currently in storage in these clinics. Nine clinics specifically offer patients the option of donating embryos to research; in total, 299 embryos have been allocated for research, about 2% of all embryos stored by these 13 clinics. All 9 clinics routinely seek consent for research use of embryos, with 7 clinics currently using such embryos for research to improve clinic practices. CONCLUSION: The results highlight the difficulties of gathering accurate data on assisted human reproduction and related research in a context where there is no legislation governing these practices. Nonetheless, the data suggest there are very few cryopreserved embryos in Canada available for research and that even fewer of these may be potentially eligible for research due to incomplete or inadequate consent processes.

Canada↗
PubMed2001

Cryopreservation of mouse embryos at morula/compact stage.

PURPOSE: The objective of this article was to study mouse morula/compact stage embryo postthaw survival rates and postthaw developmental potential. METHODS: Mouse morula/compact stage embryos were classified into 3 substages. Their morphological behavior during the freezing and thawing process were examined. Postthaw survival rates and blastocyst formation rates were compared between the three substages and the pronucleate and the 2-cell stage embryos. Finally, Postthaw fully compacted and late compact embryos were transferred to foster mothers. RESULTS: Blastomeres of early compacting embryos separated from each other during the freezing process, whereas in fully compacted and late compact stages, the blastomeres remain compacted. Fully compacted and late compact stage embryos had higher Postthaw survival rates than other stages, though those were not statistically significant (P > 0.05). These two substages had significantly higher blastocyst formation rates than Postthaw pronucleate and early compacting embryos (P < 0.01). A total of 72 Postthaw fully compacted and late compact embryos were transferred and 20 live offspring were delivered. CONCLUSIONS: After passing early compacting stage, fully compacted and late compact stage mouse embryos have high Postthaw survival rates and significantly higher blastocyst formation rates. Successful cryopreservation of embryos at these two substages has a significant value in embryo selection. The results obtained in this study may provide useful information for human assisted reproductive technology.

Animals↗
PubMed2000

The viability of transferred sheep embryos after long-term cryopreservation.

The survival to term of 414 sheep embryos, thawed and transferred after conventional cryopreservation and storage for 13 years, was evaluated. A concurrent experiment involving the transfer of vitrified embryos to 91 ewes and artificial insemination of 51 ewes with frozen-thawed semen from sires of the long-term cryopreserved embryos provided forms of control treatments. The donor ewes had a mean ovulation rate of 10.9, and 7.1 embryos per ewe were cryopreserved. Each recipient ewe received two embryos and pregnancy was assessed at Day 18, Day 54 and term. The pregnancy rate was lower in the long-term embryo group than the artificial insemination group at Day 18 (P<0.01) and Day 54 (P<0.05), although the difference at term (31% v. 49%) was not significant, with the vitrified embryo group being similar to the long-term group. Embryo survival to birth was 21%, with the majority of loss (80%) occurring by Day 18. The later stage of development and higher grade of transferred embryos and the older age of donor ewes resulted in a significantly higher (P<0.01) pregnancy rate at Day 54 and term, and percentage of lambs born and weaned. Other effects of donor ewes (genotype, superovulation treatment, number of ovulations and embryos cryopreserved) were not significant. Implications for the design of genetic evaluation and germplasm conservation programmes using embryo cryopreservation technology are discussed.

Animals↗
PubMed2002

Levels of endothelin-1 in embryos from control and neonatal streptozotocin-induced diabetic rats, and their relationship with nitric oxide generation.

Endothelin-1 (ET-1), a potent vasoconstrictor peptide and modulator of vasoactive substances such as prostanoids and nitric oxide (NO), plays an important role during embryo and fetal development. In this work, ET-1, nitrate and nitrite, and prostaglandin E2 (PGE2) levels in embryos from control and neonatal streptozotocin-induced (n-stz) diabetic rats were assessed, and the modulatory pathways regulating the generation of these vasoactive agents investigated. Endothelin-1 concentrations were found to be increased in embryos from n-stz diabetic rats when compared with controls. Additions of spermine NONOate, a nitric oxide donor, enhanced ET-1 levels in embryos from both control and n-stz diabetic rats, whereas N(G)-monomethyl-L-arginine, a nitric oxide inhibitor, diminished embryonic ET-1 content. Thus, enhanced ET-1 levels in the embryos from n-stz diabetic rats may be related to the elevated NO levels found in those embryos. Additions of ET-1 or bosentan (an endothelin A and endothelin B receptor antagonist), did not alter PGE2 generation in embryos from either control or n-stz diabetic rats. Endothelin-1 additions diminished nitrate and nitrite levels in embryos from both control and n-stz diabetic rats, whereas bosentan stimulated nitrate and nitrite generation in those embryos. In the present work, it was found that ET-1 levels were enhanced in embryos from n-stz diabetic rats, probably as a result of NO overproduction, an alteration which may be related to embryonic abnormalities and growth delay. Endothelin-1 has been shown to be a negative modulator of embryonic NO levels, a mechanism likely to be important during development. Endothelin-1 may prevent damage induced by NO overproduction in embryos from n-stz diabetic rats.

Abnormalities, Multiple↗
PubMed2003

Effect of glycosaminoglycans on the preimplantation development of embryos derived from in vitro fertilization and somatic cell nuclear transfer.

The purpose of this study was to evaluate the effect of glycosaminoglycans (GAGs) added to the culture medium on the developmental competence of bovine embryos derived from in vitro fertilization (IVF) and from somatic cell nuclear transfer (SCNT). In vitro-matured oocytes were either inseminated with 1 x 10(6) spermatozoa mL(-1) or enucleated and reconstructed with bovine adult ear fibroblasts by SCNT. The embryos were then cultured in modified synthetic oviduct fluid (mSOF) containing 8 mg mL(-1) bovine serum albumin (BSA) (control mSOF) or control mSOF supplemented with various GAGs (hyaluronic acid, heparin or chondroitin sulfate) in a dose-dependent manner (0.1, 0.5 or 1.0 mg mL(-1)). Developmental competence was evaluated by monitoring the numbers of 2-cell embryos, 8-16-cell embryos and blastocysts. The mean cell number of flattened blastocysts stained with 5 microM bisbenzimide on Day 8 was counted. The percentage of blastocyst formation (IVF and SCNT embryos) from cleaved embryos was significantly higher (P < 0.05) in control mSOF supplemented with 0.5 mg mL(-1) hyaluronic acid (45% and 47%), heparin (40% and 47%) or chondroitin sulfate (38% and 44%) compared with control mSOF (30-31% and 30-33%). When compared with the efficacy of 0.5 mg mL(-1) GAGs, no significant differences were observed in the developmental competence of both IVF and SCNT embryos. Supplementing control mSOF with 0.5 mg mL(-1) GAGs had no effect on the cell number of IVF embryos. In contrast, supplementing 0.5 mg mL(-1) of hyaluronic acid, heparin or chondroitin sulfate to control mSOF significantly (P < 0.05) increased the numbers of total cells (93-98 v. 88 cells) and trophectoderm (TE) cells (64-66 v. 55 cells), and decreased the inner cell mass (ICM) to TE cell ratio (48.2-49.8 v. 61.3) in SCNT blastocysts compared with embryos in control mSOF. In conclusion, supplementation of culture media with GAGs may improve the development of bovine IVM-IVF and SCNT embryos to the blastocyst stage. The GAGs increased the quality of blastocysts by increasing total cell numbers in the SCNT embryos.

Animals↗
PubMed1990

Development of four-cell hamster embryos to the blastocyst stage in vitro and its regulation by components of the culture milieu.

Constituents of the culture milieu known to influence development of hamster 2-cell and 8-cell embryos were examined for effects on the 4-cell stage. Embryos were collected at the mid 4-cell stage (approx. 45-46 h after egg activation) from superovulated females and cultured for 24 h in a chemically defined medium (TLP-PVA). As with the 2-cell stage, inorganic phosphate (Pi) strongly inhibited development of 4-cell embryos, although some (14%) were able to reach the 8-cell stage or further in the presence of Pi. However, unlike 2-cell embryos, no significant inhibitory effect of glucose on development of 4-cell embryos was found. In the absence of glucose and Pi, development of 4-cell embryos was sensitive to amino acids in the medium: the mean cell number was increased using 21 amino acids compared with 4 amino acids, similarly to the 2-cell stage; however, late blastocyst development (blastocele formation) from 4-cell embryos was reduced using 21 compared with 4 amino acids, as with 8-cell embryos. Similarly to the 2-cell and 8-cell stages, raising the CO2 concentration from 5% to 10% in the gas atmosphere for culture increased the percentage of total blastocysts developing from the 4-cell stage, but did not affect the proportions of late-stage blastocysts. These data show that 4-cell-stage hamster embryos are somewhat similar to 2-cell embryos with respect to the regulation of development by constituents of the culture milieu, but, to some extent, the 4-cell embryo is a transitional stage of development.

Amino Acids↗
PubMed1991

Effect of early ovariectomy and steroid hormone replacement of embryo transport, development and implantation in mice.

Bilateral ovariectomy on Day 1 of pregnancy increased abnormal embryo numbers on Day 4 and delayed passage of embryos to the uterus. Progestins given on Day 1 reversed these effects; given on Day 3 they reduced numbers of abnormal embryos, but did not restore normal transport. Oestrogen given alone after ovariectomy increased embryo loss, but restored preimplantation embryo development to normal when given on Day 3 after progestins on Day 1. The results suggested that both oestrogen and progesterone were necessary for normal preimplantation embryo development in vivo. However, although Day-1 progestins produced the greatest improvement in embryo transport and preimplantation development, they supported only low implantation rates compared with progestins starting on Day 3, and no progestin treatment returned implantation rates to normal. Sham ovariectomy on Day 1 also reduced implantation rate, suggesting that surgical stress of Day-1 ovariectomy had major adverse effects on embryo viability. This view was supported by experiments involving unilateral ovariectomy, which produced abnormalities in embryo transport, development and implantation, but only on the operated side. Furthermore, the major abnormality induced in embryo development by unilateral and bilateral ovariectomy, viz embryonic autolysis, was not increased in experiments in which pregnancy was blocked by non-surgical antagonism of progesterone. It is concluded that abnormalities in embryo development induced by early ovariectomy are not caused by a deficit of endogenous hormones, but result largely from effects of surgical trauma on oviduct function which can be reversed by treatment with exogenous hormones.

Animals↗
PubMed2002

Thioredoxin, an anti-oxidant protein, protects mouse embryos from oxidative stress-induced developmental anomalies.

During the early postimplantation period, rodent embryos survive in a relatively anaerobic environment in utero and are vulnerable to a high oxygen pressure. They become resistant to oxygen stress when they are exposed to a higher oxygen pressure after the uteroplacental circulation is established. However, it is unknown how embryos acquire such resistance against oxidative stress. This study was undertaken to examine whether an antioxidant protein thioredoxin (TRX) plays a significant role in the embryonic acquisition of the tolerance to oxidative stress. E7.5 embryos of C57BL/6 wild-type (WT) and human TRX (hTRX) inserted-transgenic (Tg) embryos were cultured under 10 or 25% O2 and their growth and morphological differentiation were evaluated. The TRX expression and the products of oxidative stress (8-hydroxy-2'-deoxy-guanosine and carbonylated proteins) in their tissues were also examined. When WT embryos were cultivated in vitro under 25% O2, their growth was significantly disturbed and various developmental abnormalities were induced, which did not occur in embryos grown under 10% O2. However, such embryotoxic effects of oxygen were significantly attenuated in the hTRX Tg embryos that continuously express hTRX. Accumulation of the products of oxidative stress was significantly reduced in hTRX Tg embryos as compared with that in WT embryos. The TRX transgene appears to provide the embryo with the resistance against oxidative stress and may play a crucial role in the redox regulation in embryos.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2005

Development of interspecies cloned embryos in yak and dog.

Interspecies nuclear transfer (NT) could be an alternative to replicate animals when supply of recipient oocytes is limited or in vitro embryo production systems are incomplete. In the present study, embryonic development was assessed following interspecies NT of donor cumulus cells derived from yak and dog into the recipient ooplasm of domestic cow. The percentages of fusion and subsequent embryo development to the eight-cell stage of interspecies NT embryos were comparable to those of intraspecies NT embryos (cow-cow NT embryos). The percentage of development to blastocysts was significantly lower (p < 0.05) in yak-cow NT embryos than that in cow-cow NT embryos (10.9% vs. 39.8%). In dog-cow NT embryos, only one embryo (0.4%) developed to the blastocyst stage. These results indicate that interspecies NT embryos possess equally developmental competence to the eight-cell stage as intraspecies NT embryos, but the development to blastocysts is very low when dog somatic cells are used as the donor nuclei.

Animals↗
PubMed1998

Detection of reactive oxygen species (ROS) and apoptosis in human fragmented embryos.

In human in-vitro fertilization (IVF)-embryo transfer, the in-vitro culture environment differs from in-vivo conditions in that the oxygen concentration is higher, and in such conditions the mouse embryos show a higher concentration of reactive oxygen species (ROS) in simple culture media. ROS are believed to cause damage to cell membranes and DNA fragmentation in somatic cells. This study was conducted to ascertain the level of H2O2 concentration within embryos and the morphological features of cell damage induced by H2O2. A total of 62 human oocytes and embryos (31 fragmented, 15 non-fragmented embryos, 16 unfertilized oocytes) was obtained from the IVF-embryo transfer programme. The relative intensity of H2O2 concentrations within embryos was measured using 2',7'-dichlorodihydrofluorescein diacetate by Quanti cell 500 fluorescence imaging and DNA fragmentation was observed with transmission electron microscopy and an in-situ apoptosis detection kit. The H2O2 concentrations were significantly higher in fragmented embryos (72.21 +/- 9.62, mean +/- SEM) compared to non-fragmented embryos (31.30 +/- 3.50, P < 0.05) and unfertilized oocytes (30.75 +/- 2.67, P < 0.05). Apoptosis was observed only in fragmented embryos, and was absent in non-fragmented embryos. Electron microscopic findings confirmed apoptotic bodies and cytoplasmic condensation in the fragmented blastomeres. We conclude that there is a direct relationship between increased H2O2 concentration and apoptosis, and that further studies should be undertaken to confirm these findings.

Apoptosis↗
PubMed1999

In-vitro matured metaphase-I oocytes have a lower fertilization rate but similar embryo quality as mature metaphase-II oocytes after intracytoplasmic sperm injection.

About 4% of all the oocytes denuded prior to intracytoplasmic sperm injection (ICSI) are in metaphase-I (MI). Frequently, these oocytes achieve meiosis after a few hours of in-vitro culture and are available for ICSI on the day of oocyte retrieval. In this retrospective study, the aim was to evaluate the fertilization rate and the developmental capacity of these in-vitro matured MI oocytes. After controlled ovarian stimulation using human menopausal gonadotrophin (HMG) and human chorionic gonadotrophin (HCG) in 896 ICSI cycles, 1210 MI-to-MII-matured oocytes were injected approximately 4 h after in-vitro culture and 8803 MII oocytes were injected immediately, or later, after denudation. The fertilization rate of in-vitro matured oocytes was significantly lower than that of mature MII oocytes (52.7 and 70.8% respectively, P < 0.00l). Embryo quality was only slightly different as regards the numbers of good quality embryos: 47.4% good quality embryos were obtained in the in-vitro matured oocyte group, whereas 53.2% good quality embryos were obtained in the MII oocyte group (P < 0.05). The same proportions of excellent (5.7 and 7.0%, NS) and fair quality (17.6 and 15.3%, NS) embryos were obtained for in-vitro matured and mature oocytes respectively. Embryos derived from in-vitro matured oocytes were transferred only if they were of better quality or if there were not enough mature oocyte derived embryos available. Fifteen transfers involved only embryos derived from in-vitro matured oocytes: 11 single embryo transfers and four transfers of two embryos, resulting in one singleton pregnancy and the birth of a healthy baby. It may be concluded that in cycles with few MII oocytes it might be worthwhile to inject in-vitro matured MI oocytes in order to increase the number of embryos available for transfer.

Cell Differentiation↗