Controlled natural cycle IVF with antagonist use and blastocyst transfer.

A method of controlled natural cycle IVF (CONCIVF) was sought to provide simpler and shorter treatment without the risks of ovarian hyperstimulation syndrome and multiple pregnancies. A total of 138 couples with normal ovulation and normal sperm parameters, in whom the women were <40 years old, were the candidates for this study. Gonadotrophin-releasing hormone antagonist was used before human chorionic gonadotrophin (HCG) administration if LH increased to a concentration of 10 mIU/ml before HCG injection. Treatment was initiated at > or =16 mm follicular growth and at oestradiol concentrations > or =400 pmol/l with 5000 IU HCG induction. All the embryos were cultured to the blastocyst stage and transferred only if they reached early or advanced blastulation. A total of 126 patients underwent oocyte retrieval. In 102 cases, one oocyte was retrieved; 95% of the oocytes fertilized, 99% cleaved and 47.9% achieved the blastocyst stage. The implantation rate per blastocyst transfer was 53.3% and the live-birth rate per embryo transfer was 40%. Therefore, CONCIVF with blastocyst transfer gives acceptable blastocyst development and implantation rates without the long- or short-term side effects of ovulation induction.