Sex ratio and birth weights of infants born as a result of blastocyst transfers compared with early cleavage stage embryo transfers.

Objective: To analyze the birth weights and sex ratio of infants born as a result of blastocyst transfer and compare them with data resulting from the transfer of early-cleavage stage embryos.

Design: Retrospective analysis.

Setting: Monash IVF (private in vitro fertilization clinic).

Oocyte maturation.

Primary oocytes recovered from small and growing follicles of > or = 3 mm in the ovaries of untreated women, can be matured in vitro, will fertilize and develop in vitro, and when transferred to the patient, develop to term. However, the implantation rate of cleaved embryos has been disappointingly low and when embryos are allowed to develop beyond the 4-cell in vitro, retardation of development and blockage is frequently observed, with relatively few embryos developing to blastocysts. We have devised new culture systems for human embryos to enable high rates of development of in-vivo matured oocytes to blastocysts within 5-6 days of culture, and high implantation rates of these blastocysts when they are transferred to the patients' uterus.

Evolution of a culture protocol for successful blastocyst development and pregnancy.

A cell-free culture system was designed for human embryo development to the blastocyst stage by testing a range of culture conditions in a series of protocols. The culture system that was evolved has a brief 1 h exposure to spermatozoa and then culture of the pronucleate zygote for 2 days in IVF-50 medium. Two or three embryos were cultured together in 20 microl microdrops of medium under oil.

Is the acrosome reaction a prerequisite for sperm incorporation after intra-cytoplasmic sperm injection (ICSI)?

There is debate as to whether the acrosome reaction is necessary for sperm incorporation after intra-cytoplasmic sperm injection (ICSI). Ultrastructural evidence is presented to show that the acrosome reaction could occur in the ooplasm before sperm incorporation in mature human oocytes or the acrosome could be discarded intact before sperm incorporation in immature oocytes, matured in vitro. Both germinal vesicle and growing follicular oocytes showed sperm chromatin decondensation, with discarded acrosomes close to the sites of incorporation, and were able to form male pronuclei.

Production of embryos from in vitro-matured primary human oocytes.

Objective: To determine the factors that influence the number and quality of embryos produced from primary oocytes collected from untreated regularly ovulating and irregular or anovulatory polycystic women.

Design: A direct comparison between two patient groups whose oocytes were matured in vitro and a comparison of the embryo development of in vitro-matured oocytes from untreated patients with in vivo-matured oocytes of superovulated IVF-ET patients obtained during the same period.

Setting: The Monash IVF Clinic, involving patients who expressed the desire to avoid super-ovulation with fertility drugs.