Current problems in human in vitro fertilization and embryo implantation

Abstract

Recently, in several centers, there have been striking in creases in the pregnancy rates from human in vitro fertilization (IVF). Some of the improvements are 1) refinement and individualization of ovulation induction with clomiphene citrate and human menopausal gonadotropin and timing of hCG administration, aided by monitoring of plasma estradiol, cervical mucus characteristics, and follicle size and number; 2) preincubation of oocytes before insemination; 3) improvements in embryo transfer procedures, including smaller diameter catheters, smaller fluid volume, and the inclusion of a high proportion of serum in the transfer medium. Although there are still unresolved problems at all stages it would be of significant assistance to the induction and culture if a noninvasive monitor of oocyte maturity and health were available. The appearance of the living oocyte under the light microscope has proved of limited diagnostic value. With this aim in mind, the microscopic appearance of cumulus cells and follicular fluid protein levels have been assessed with respect to their usefulness in indirect oocyte assessment. Follicular fluid proteins from patients who had become pregnant after the transfer of a single embryo have been separated by broad spectrum pH isoelectric focusing. The complex band profiles were quantitated by laser beam densitometry. Statistical analyses of the results, grouped according to the performance of the oocyte and resulting embryo following IVF, indicate that there are differences between the groups in which the oocytes fertilized, cleaved, and produced pregnancies and those which did not. Further studies are underway to assess the predictive value of the individual isoelectric focusing profiles. Also being investigated is their possible usefulness in monitoring ovulation induction regimens.