Recently, it has been suggested that culture of embryos in EmbryoGen medium can increase the live birth rate in IVF patients with a previous history of pregnancy loss.

Couples requiring IVF treatment and with a past experience of implantation failure will be included in the study.

Controlled ovarian stimulation protocol will consist of an agonist down regulation and follicular stimulation by recombinant FSH. Fertilization will be achieved by standard IVF or intracytoplasmic sperm injection. Fertilized eggs will be cultured in 6% CO2, 5% O2, 89% N2 atmosphere in microdrops. In the treatment group EmbryoGen culture medium (EG, Origio, Måløv, Denmark) will be adopted throughout the culture period. In the control group, inseminated oocytes will be cultured in standard culture conditions, i.e. IMS1 medium (ISM1, Origio, Måløv, Denmark), maintaining unchanged all other culture conditions.

Procedures of embryo transfer, will be carried out on day 2 using EmbryoGen or ISM1 respectively. The endometrial support will be the same in the two groups.

Inclusion Criteria:

• women experiencing at least two (maximum 4) failures of implantation after ART treatments (with elective embryo transfer)

Exclusion Criteria:

• Frozen spermatozoa
• Frozen oocytes
• women PCO and PCOS
• women with previous pregnancy, miscarriage or biochemical pregnancy

Infertile couple with an indication for standard IVF or intracytoplasmic sperm injection. Moreover all couples had previous implantation failures after ART treatment (minimun 2 maximun 4 embryo replacements).