A comparative analysis of embryo implantation potential in patients with severe teratozoospermia undergoing in-vitro fertilization with a high insemination concentration or intracytoplasmic sperm injection

The objective of this study was to assess fertilization, implantationand pregnancy rates in infertile patients with severe teratozoospermiaP (poor prognosis) pattern sperm morphology assessed by strictcriteria] treated by in-vitro fertilization (IVF) using a highinsemination concentration (HIC), or by intracytoplasmic sperminjection (ICSI). This was a retrospective cohort study performedin an academic tertiary institution. The outcome of 115 consecutiveICSI cycles was compared to that of a similar number of cyclesof IVF with HIC performed during a similar time frame and matchedby woman's age and basal serum (cycle day 3) follicle stimulatinghormone concentrations. The inclusion criteria were sperm morphology4% normal forms (P pattern) and 1 x106 total motile spermatozoaper ejaculate. The diploid fertilization rate in the HIC-IVFgroup was 86% and in the ICSI group 68% (P < 0.05). Importantly,an equal number of embryos was transferred to both groups ofpatients. The morphological quality of the embryos (proportionof transfers having superior morphology embryo scores) was significantlybetter in the ICSI group than in the patients receiving HIC-IVF.Although there was a clear trend for better implantation andpregnancy rates in the ICSI group, these differences were notstatistically significant We conclude that, although HIC-IVFresulted in a higher fertilization rate than ICSI in patientswith severe teratozoospermia, ICSI produced a significantlyhigher proportion of morphologically superior embryos with atendency towards a higher implantation potential. Therefore,teratozoospermic patients having adequate numbers of motilespermatozoa should be offered ICSI as an alternative to modified(HIC) IVF treatment.