Relationship between first polar body morphology before intracytoplasmic sperm injection and fertilization rate, cleavage rate, and embryo quality

Abstract

OBJECTIVES: To evaluate the influence of the morphology of the first polar body (PB) on intracytoplasmic sperm injection (ICSI) outcomes. METHODS: The morphology of the first PB was assessed in 3177 metaphase II oocytes and classified as: intact and normal size, fragmented, or enlarged size. The rates of fertilization, cleavage, and embryo quality were evaluated on day 2. RESULTS: The rates of fertilization, cleavage, and formation of good quality embryos resulting from the insemination of oocytes with an enlarged first PB (20.7%, 18.7%, and 5.0%, respectively) were significantly lower than those for oocytes with an intact first PB of normal size (70.8%, 62.5%, and 19%, respectively) or a fragmented first PB (69.7%, 60.5%, and 17.1%, respectively). Rates did not differ significantly between oocytes with an intact first PB of normal size and oocytes with a fragmented first PB (P>0.05). CONCLUSIONS: The presence of an enlarged PB is related to poorer rates of fertilization, cleavage, and top quality embryos. However, identification of first PB fragmentation does not seem to interfere with ICSI outcomes.