Math H.E.C. Pieters

Implantation rates after in vitro fertilization and transfer of a maximum of two embryos that have undergone three to five days of culture

OBJECTIVE To evaluate implantation and pregnancy rates in patients undergoing IVF after the transfer of a maximum of two embryos that had been cultured for 3-5 days. DESIGN Prospective study. SETTING An IVF laboratory at a tertiary referral university hospital. PATIENT(S) One thousand seven hundred eighty-seven couples who underwent their first IVF cycle between January 1995 and December 1997. INTERVENTION(S) In vitro fertilization and transfer of embryos after 3, 4, or 5 days of culture using a single medium without coculture. MAIN OUTCOME MEASURE(S) Implantation and pregnancy rates. RESULT(S) Overall implantation and pregnancy rates were not significantly different with different culture periods. Forty-one percent of all available embryos developed into blastocysts on day 5. The transfer of at least one good-quality blastocyst could be performed in 62% of patients. Blastocysts had an implantation rate of 26% per embryo, whereas the implantation rate of eight-cell embryos on day 3 was 18%. Implantation rates for retarded, normal, and advanced embryos were not significantly different with an extended culture period. CONCLUSION(S) Under the study conditions, the transfer of embryos after 5 days rather than 3 days of embryo culture did not change the overall implantation and pregnancy rates. The implantation potential of embryos available for transfer can be assessed better after an extended culture period. Five days of culture allows the transfer of a reduced number of embryos without decreasing overall pregnancy rates.

A prediction model for selecting patients undergoing in vitro fertilization for elective single embryo transfer

OBJECTIVE Construction of a prediction model to enable the selection of patients for elective single ET. DESIGN Retrospective cohort study. SETTING Fertility center in a tertiary referral university hospital. PATIENT(S) Six hundred forty-two women undergoing their first IVF treatment cycle in which no more than two embryos were transferred. INTERVENTION(S) Database analysis. MAIN OUTCOME MEASURE(S) Ongoing pregnancy and multiple pregnancy. RESULT(S) In multivariate analysis, the best predictors for ongoing pregnancy were female age, the number of retrieved oocytes, the developmental stage score and the morphology score of the two best embryos available for transfer, and the day of transfer. Younger age and high quality of transferred embryos were the best predictors for increased risk of multiple pregnancy. The resulting model enables the calculation of probabilities of pregnancy and twin pregnancy. Depending on embryo quality, there is a threshold age under which the chance of singleton pregnancy is higher if one embryo is transferred compared with two embryos. CONCLUSION(S) Application of this model may enable a reduction in the chance of twin pregnancy without compromising singleton pregnancy rates in a subgroup of patients undergoing IVF.

Cytogenetic analysis of in vitro fertilization (IVF) failures.

SummaryCytogenetic studies were carried out on 150 oocytes obtained in a human in vitro fertilization (IVF) program. Although all cells lacked signs of fertilization at light microscopy, 46 (30.7%) appeared to show cytological evidence of fertilization. At least one-third of these cells (with development arrested before first cleavage) had chromosomal aberrations. An aneuploidy rate of 35% was found in unfertilized oocytes. The results of this study explain some of the fertilization failures and of the failures of postfertilization development.

Immaturity and aneuploidy in human oocytes after different stimulation protocols

OBJECTIVE To study immaturity and aneuploidy in human oocytes after two different stimulation protocols. DESIGN Retrospective. SETTING Outpatient IVF clinic/laboratory. PATIENTS One hundred forty-three patients of whom 65 were stimulated with clomiphene citrate (CC)/human menopausal gonadotropin (hMG) and 78 were stimulated with gonadotropin-releasing hormone agonist (GnRH-a)/hMG. Only patients with at least one oocyte unfertilized were included in this study. RESULTS Stimulation with GnRH-a/hMG, as compared with CC/hMG stimulation, resulted in larger numbers of oocytes (P less than 0.00001), a higher fertilization rate (P less than 0.02), and oocyte retrieval at a later average cycle day (P less than 0.000005). Cytogenetic findings of immaturity were observed in 33.9% of unfertilized oocytes after CC/hMG stimulation, compared with only 17.8% after GnRH-a/hMG stimulation (P less than 0.0005). Aneuploidy findings were the same for both groups. CONCLUSION In GnRH-a/hMG stimulation, oocytes approach the normal day of ovulation more closely. This may allow for better oocyte maturation and higher fertilization and pregnancy rates.

Current progress in preimplantation genetic diagnosis

Preimplantation genetic diagnosis (PGD) was first undertaken for X-linked diseases in 1989 (1) and for autosomal recessive conditions in 1990 (2). Since then children without detectable birth defects have been born following the procedure, presenting evidence for possible clinical application (3-9). However, two misdiagnosis have also been reported, showing the need for further development and improvement (10,11). The Third Annual Meeting of the International Working Group was organized in .association with the ESHRE-93 meeting to update the clinical experience of centers performing or setting up PGD, to review techniques and problems of PGD of single-gene and chromosomal diseases, to develop a standardized format for reporting the data, and to review national attitudes and legal status of PGD in different countries.

RS46(DXS548) genotyping of reproductive cells : approaching preimplantation testing of the fragile-X syndrome

In order to approach preimplantation testing for the fragile-X syndrome, we used genotyping of the polymorphic RS46(DXS548) locus closely linked to the FMR1 gene, in single reproductive cells of females. The RS46(DXS548) amplification was adjusted to the single cell level by a two-round polymerase chain reaction (PCR) procedure. Unfertilized oocytes and extruded polar bodies were subjected to PCR. RS46(DXS548) genotyping at the single cell level was successful in 95% of the samples. In two-third of the metaphase II oocytes and first polar bodies obtained from women who were heterozygous at the RS46(DXS548) locus, both maternal RS46(DXS548) alleles were observed because of crossing over during the first meiotic division. This makes gamete selection by first polar body analysis inefficient. From the allele frequencies found in 56 unrelated individuals, a heterozygote frequency of 51% was estimated, whereas the observed heterozygote frequency was 56%. The whole PCR procedure can be performed within 16 h after blastomere biopsy. Consequently, the selection and transfer of the diagnosed embryos can be carried out within an acceptable time. Therefore, preimplantation testing for the fragile-X syndrome with the RS46(DXS548) AC-repeat may be an alternative choice for prenatal testing for those carrier females who are heterozygous (informative) at the RS46(DXS548) locus.