Embryo implantation in in vitro fertilization and intracytoplasmic sperm injection: impact of cleavage status, morphology grade, and number of embryos transferred.

Objective: The aims of this study were to compare preimplantation embryo quality in intracytoplasmic sperm injection (ICSI) with standard IVF and to examine the impact of age and number and quality of embryos transferred on implantation and pregnancy.

Design: Retrospective, controlled clinical study.

Setting: Academic tertiary center.

Patient(s): We examined 211 consecutive couples undergoing ICSI who were matched with 211 couples undergoing IVF therapy during the same time frame.

Intervention(s): In vitro embryo culture.

Main Outcome Measure(s): Day 3 embryo quality as judged by the number of blastomeres and morphology scoring.

Result(s): Patients undergoing ICSI had a significantly reduced number of embryos with good morphology and cleavage compared with IVF cases. Nevertheless, pregnancy and abortion rates were similar when adjusted by age and number of embryos transferred. Average cleavage status and age were significant predictors of implantation. Women of advanced age had significantly lower embryo cleavage and implantation rates.

Conclusion(s): [1] The cleaving status of day 3 embryos is a valuable, although limited, indicator of implantation outcome. [2] In vitro fertilization-derived embryos had better cleavage rates and morphology scores than ICSI-derived embryos; however, the implantation potential was similar for both groups. [3] The age-related decline in implantation rate was associated with impaired embryo growth rates.