Our results showed that survival rates in cryopreserved expanded blastocysts could be improved by reducing the fluid content. This was presumably because mechanical damage caused by ice crystal formation was avoided. These observations should be considered when establishing a strategy and a protocol for cryopreservation of day 5 embryos.

The multicentric study regroups 128 cases of the ovarian hyperstimulation syndrome (OHSS) in in-vitro fertilization (IVF) and 256 selected controls. Values of serum oestradiol obtained from different laboratories were found to be normally distributed after logarithmic transformation. Comparative study of clinical and biological characteristics indicates that among OHSS patients (i) mean age was lower; (ii) tubal indications for IVF were less frequent; (iii) polycystic ovary-like conditions (i.e. hyperandrogenism, anovulation, luteinizing hormone/follicle stimulating hormone ratio > 2) were more frequent. OHSS patients displayed ovarian hypersensitivity reflected by higher oestradiol peak concentrations in response to lower dosage of human menopausal gonadotrophin and by a steeper slope of oestradiol increment during stimulation. In these patients, the collection of greater numbers of fertilizable oocytes allowed replacement of more embryos with a good vitality score. Ongoing pregnancy rate was found to be higher among the OHSS patients. The following complications were recorded among OHSS cases: abdominal fluid at echographic examination or clinical ascites (86.7 and 71.1%, respectively); pleural and pericardial effusion (21 and 3%, respectively); haemoconcentration (71.1%); electrolytic disorders (6.2%). Although significantly different between groups, clinical and biological parameters under study showed considerable overlap of their distributions in control and OHSS cases. Therefore, these data must be submitted to discriminant analysis in order to derive a formula predictive of the risk of OHSS.

No abstract

The aim of this work was to evaluate the relationship between follicular size at the time of oocyte retrieval, and the subsequent oocyte competence to be fertilized and to develop in vitro. All the obtained oocytes were classified according to the corresponding volume of aspirated follicular fluid. Aspirated volume of follicular fluid <2 ml corresponded to a follicular diameter <16 mm and constituted the small size group. Volume of follicular fluid from 2 to 6 ml corresponded to a diameter from 16 to 23 mm and constituted the medium size group. The large size group contained follicles with diameter >23 mm and corresponded to an aspirated volume of follicular fluid of >6 ml. A progressive and significant increase in the rates of oocytes with a first polar body was observed from the small size group to the other groups and from the medium to the large size group: 75.3, 85.9 and 95.3% respectively. After classical in-vitro fertilization (IVF), significantly better rates of fertilization and development were obtained in the medium size group compared to the two other groups. Moreover, a positive relationship was observed between follicular diameter and rates of embryos scored as 'good' when oocytes were fertilized by intracytoplasmic sperm injection (ICSI). These results demonstrated that follicular size is positively related to the oocyte ability to be fertilized and to develop. Although oocytes from small follicles gave lower percentages of development probably due to partial oocyte incompetence, they allowed an increase in the total number of embryos scored as 'good'.

Sometimes spermatozoa from ejaculate, epididymis or testis show a total absence of motility. For some patients, however, very few spermatozoa with very poor motility can be found after several hours of incubation (initially immotile spermatozoa). Other samples show no motility at all even after extended culture (totally immotile spermatozoa). Intracytoplasmic sperm injection (ICSI) is the only method available to select and retrieve a single immotile or initially immotile spermatozoon and inject it into the oocyte. A total of 103 patients with asthenozoospermia underwent ICSI in this study. It was shown that initially immotile and totally immotile spermatozoa, whatever their origin, have the capacity to fertilize an oocyte after ICSI. No significant difference could be observed between the fertilizing capacity of testicular or epididymal spermatozoa. Totally immotile ejaculated spermatozoa, however, fertilized significantly fewer oocytes after ICSI when compared with initially immotile ejaculated spermatozoa. Embryos of lower quality tended to be produced when totally immotile spermatozoa of any origin were used, compared with embryos resulting from initially immotile spermatozoa. Ongoing pregnancies were conceived after ICSI with initially immotile spermatozoa from any origin and totally immotile spermatozoa retrieved from testis only. One biochemical pregnancy was the result of embryo transfer after ICSI with totally immotile ejaculated spermatozoa. No supernumerary embryos could be cryopreserved for patients with totally immotile spermatozoa from ejaculate or epididymis. For a Kartagener patient, subzonal insemination (SUZI) seemed to be a better approach for obtaining fertilization and pregnancy than ICSI because no fertilization occurred after ICSI on sibling oocytes. Hence a healthy pregnancy was obtained after SUZI.