Human oocytes containing large cytoplasmic vacuoles can result in pregnancy and viable offspring.

The effect of oocyte dysmorphism on further embryo development is controversial. It is generally accepted that serious oocyte abnormalities can have a negative effect on further fertilization and development. A couple reported to the clinic following 2 years of infertility and underwent five IVF/intracytoplasmic sperm injection treatments due to severe male factor infertility. A total of 42 oocytes were collected. The majority of the oocytes showed at least one large, fluid-filled and centrally located cytoplasmic vacuole and unusually thin zona pellucida. Only seven oocytes showed normal fertilization. The first four IVF treatments did not result in pregnancy. In the fifth IVF treatment, three poor-quality vacuolized embryos were transferred. A singleton pregnancy was detected. A baby girl was born at term who required surgery because of a double left kidney and ureter. This case report demonstrates that serious oocyte abnormalities can be a recurrent phenomenon in the same patient. However, the presence of a large vacuole does not completely block the fertilization process and this abnormal cohort of oocytes can still result in normal embryo development and a viable offspring. Rigorous prenatal care and follow-up should be carried out following the transfer of embryos developed from dysmorphic oocytes.

Impact of GnRH analogues on oocyte/embryo quality and embryo development in in vitro fertilization/intracytoplasmic sperm injection cycles: a case control study.

BACKGROUND: Despite the clinical outcomes of ovarian stimulation with either GnRH-agonist or GnRH-antagonist analogues for in vitro fertilization (IVF) being well analysed, the effect of analogues on oocyte/embryo quality and embryo development is still not known in detail. The aim of this case-control study was to compare the efficacy of a multiple-dose GnRH antagonist protocol with that of the GnRH agonist long protocol with a view to oocyte and embryo quality, embryo development and IVF treatment outcome. METHODS: Between October 2001 and December 2008, 100 patients were stimulated with human menopausal gonadotrophin (HMG) and GnRH antagonist in their first treatment cycle for IVF or intracytoplasmic sperm injection (ICSI). One hundred combined GnRH agonist + HMG (long protocol) cycles were matched to the GnRH antagonist + HMG cycles by age, BMI, baseline FSH levels and by cause of infertility. We determined the number and quality of retrieved oocytes, the rate of early-cleavage embryos, the morphology and development of embryos, as well as clinical pregnancy rates. Statistical analysis was performed using Wilcoxon's matched pairs rank sum test and McNemar's chi-square test. P < 0.05 was considered statistically significant. RESULTS: The rate of cytoplasmic abnormalities in retrieved oocytes was significantly higher with the use of GnRH antagonist than in GnRH agonist cycles (62.1% vs. 49.9%; P < 0.01). We observed lower rate of zygotes showing normal pronuclear morphology (49.3% vs. 58.0%; P < 0.01), and higher cell-number of preembryos on day 2 after fertilization (4.28 vs. 4.03; P < 0.01) with the use of GnRH antagonist analogues. The rate of mature oocytes, rate of presence of multinucleated blastomers, amount of fragmentation in embryos and rate of early-cleaved embryos was similar in the two groups. Clinical pregnancy rate per embryo transfer was lower in the antagonist group than in the agonist group (30.8% vs. 40.4%) although this difference did not reach statistical significance (P = 0.17). CONCLUSION: Antagonist seemed to influence favourably some parameters of early embryo development dynamics, while other morphological parameters seemed not to be altered according to GnRH analogue used for ovarian stimulation in IVF cycles.