Follicular and endocrine profiles associated with different GnRH-antagonist regimens: a randomized controlled trial.

This trial assessed the impact of early initiation of gonadotrophin-releasing hormone (GnRH) antagonist on follicular and endocrine profiles compared with the fixed GnRH-antagonist protocol. Eighty-five oocyte donors were randomized to GnRH antagonist starting in the mid-luteal phase of the prestimulation cycle (degarelix-ML group), on stimulation day 1 (early follicular phase, degarelix-EF group) or day 6 (fixed protocol) (mid-follicular phase, ganirelix-MF group). Subjects in the degarelix-EF and ganirelix-MF groups received placebo in the prestimulation cycle. At start of stimulation, serum concentrations of FSH (4.6 ± 2.3 versus 6.0 ± 1.8IU/l), LH (2.7 ± 1.4 versus 4.7 ± 1.9IU/l) and oestradiol (87 ± 35 versus 129 ± 50pmol/l) were markedly lower (P<0.001) in the degarelix-ML group than in the placebo group. The coefficients of variation of follicle size (36.7 ± 5.5% versus 39.2 ± 9.4%) were not significantly different. No differences in endometrial histology, embryo quality and pregnancy rates in recipient cycles were observed between the regimens. In conclusion, early administration of GnRH antagonist altered the endocrine profile without modifying the follicular synchrony for the majority of subjects. Whether patients with a more heterogeneous follicle size at start of stimulation may benefit from an earlier intervention remains to be proven.

Evaluation of reproductive potential after intracytoplasmic sperm injection of varied human semen tested by antiacrosomal antibodies.

OBJECTIVE: To determine whether varied human spermatozoa, as detected with monoclonal antibodies against acrosomal proteins, have an influence on fertilization, transfer, pregnancy, and implantation rates when intracytoplasmic sperm injection is used. DESIGN: A retrospective study. SETTING: A private IVF center and academic research laboratory. PATIENT(S): One thousand two hundred forty men participating in the intracytoplasmic sperm injection program. INTERVENTION(S): Sperm were divided into seven groups: oligozoospermia, oligoasthenozoospermia, and oligoasthenoteratozoospermia and fresh and frozen-thawed epididymal and fresh and frozen-thawed testicular sperm. Fertilization, transfer, pregnancy, and implantation rates were recorded in each category. Sperm were tested with antibodies for detection of the of the sperm acrosome. MAIN OUTCOME MEASURE(S): Fertilization, transfer, pregnancy and implantation rates, and percentage of acrosome-reacted cells. RESULT(S): The fertilization rate and statistical evaluation showed differences between morphologically normal and pathological sperm and other groups. The freezing-thawing procedure had no influence on the fertilization of testicular sperm, but epididymal frozen-thawed sperm had a higher fertilization rate. Immunofluorescence proved decreasing sperm quality in all groups compared with the control group. This difference is not manifested in other parameters (transfer, pregnancy, implantation rates). CONCLUSION(S): The spermatozoa with varied semen characteristics and good quality, also detected with specific antibodies, gave the best fertilization rates. The paternal effect is not proved in other parameters.

DNA methylation pattern in human zygotes and developing embryos.

We report on observations of the global methylation/demethylation pattern of both pronuclei in human zygotes and in early embryos up to the blastocyst stage. Our results demonstrate that in about half of the zygotes examined the paternal chromatin was less methylated than the maternal chromatin. In the other half, both pronuclei exhibited the same intensity of labeling. The nuclei in developing embryos were intensively labeled for up to the four-cell stage; thereafter, a decline of labeling intensity was detected. Remethylation in some nuclei starts in late morulae. Surprisingly, and unlike the mouse, at the blastocyst stage the inner cell mass showed a weaker intensity of labeling than the trophectodermal cells.

Failure of oocyte maturation: possible mechanisms for oocyte maturation arrest.

For human IVF, the patient's ovaries are hormonally stimulated to ensure the collection of fully matured oocytes that are at the metaphase II stage. Only these oocytes can be successfully fertilized either when mixed with sperm or after ICSI. Nevertheless, in some cases immature or maturing oocytes are recovered from follicles. Surprisingly, sometimes these oocytes do not complete maturation when cultured in vitro, for unknown reasons. In this article we discuss some possible mechanisms that may be responsible for those atypical arrests.