The aim of this study was to investigate whether equally high-quality embryos derived from standard in vitro fertilization (IVF) or from intracytoplasmic sperm injection (ICSI) differ in pregnancy potential. We evaluated all consecutive cycles from January 1996 to December 1997, in which only high-quality embryos were transferred. A total of 171 IVF and 148 ICSI cycle procedures, conducted in 153 and 130 women respectively, met with the inclusion criteria. A higher clinical pregnancy rate was recorded for the IVF group than the ICSI group (35% versus 29% respectively), although the difference did not achieve statistical significance. This result was detected despite the significantly higher mean age of the IVF patients compared with the ICSI patients (35 ± 4.9 years and 33 ± 5.2 years respectively). Controlling for the effect of patient age using linear regression analysis yielded a significantly higher clinical pregnancy rate for IVF therapy. In conclusion, IVF is associated with a significantly higher clinical pregnancy rate than ICSI even when high-quality, morphologically comparable embryos are utilized.
- Embryo morphology