OBJECTIVETo determine an optimal insemination technique for patients suspected of high risk of fertilization failure and undergoing assisted reproduction treatment.

METHODSNinety-nine couples were treated by conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) in one cycle (half-ICSI) by dividing the sibling oocytes in halves. The clinical and laboratory data were analyzed, and the rates of fertilization, cleavage, good embryos and clinical pregnancy were compared between different fertilization methods.

RESULTSIn the half-ICSI group, the fertilization rate of ICSI (80.5%) was significantly higher than that of IVF (42.9%) (P < 0.01), and so were the rates of complete fertilization failure (21.2%) and low fertilization (16.2%) of IVF than those of ICSI (0 and 3.0%). No significant differences were observed in the rates of cleavage and good-quality embryos between the two groups (P > 0.05).

CONCLUSIONICSI can help to avoid complete fertilization failure, achieve more high quality embryos for transfer and improve the rate of pregnancy for patients with high risk of fertilization failure.