Assisted Reproductive Techniques (ART) separating oocytes in sibling oocytes treated either by conventional IVF or ICSI is called mid-IVF/ICSI. We sum up here 487 attempts of this kind from six French ART centers. The mid-IVF/ICSI technique was performed in 5.6% of cases. The fertilization rate by micro-injected oocytes was significantly higher (P<0.01) than oocytes inseminated conventionally, 72.6% versus 53.4%. A failure of fertilization was observed only in mid-IVF in 21.6% of cases, which prevented a complete fertilization failure when we decided to propose to the couples concerned the mid-IVF/ICSI technique. Conversely, in 75.2% of cases, fertilization was found for the two batches of oocytes. The overall pregnancy rate has improved since the use of the mid-IVF/ICSI technique (33.1% versus 28.9%, P=0.013) and the fertilization failures decreased (10.4% versus 14.3%, P=0. 019). The pregnancy rate in only mid-IVF/ICSI cases is very high at 39.8% but for a selected population. The indications for mid-IVF/ICSI remain to be clarified especially with regard to male and idiopathic indications.
