SPERM MORPHOLOGY AS DIAGNOSED BY STRICT CRITERIA - PROBING THE IMPACTOF TERATOZOOSPERMIA ON FERTILIZATION RATE AND PREGNANCY OUTCOME IN A LARGE IN-VITRO FERTILIZATION POPULATION

Objective: To investigate the predictive value of sperm morphology ass essed by strict criteria on IVF outcome. Design: Retrospective analysi s of all IVF cycles (January 1987 to December 1992). Main Outcome Meas ures: All patients were assigned to one of three groups based on sperm morphology: P-pattern (<4% normal forms), G-pattern (4% to 14% normal forms), and N-pattern (>14% normal forms). Morphology pattern was rel ated to other semen characteristics and IVF outcome. Results: Despite corrective measures at oocyte insemination, the fertilization rate was significantly different among the three morphology groups, P < G < N. N-pattern sperm produced a mean fertilization rate over 85% regardles s of low motility or concentration. In a cohort study, P-pattern cycle s produced a lower implantation rate and lower ongoing pregnancy rate, independent of the lower fertilization rate. Conclusions: Strict morp hology is an excellent biomarker of sperm fertilizing capacity, indepe ndent of motility and concentration. P-pattern sperm may denote a poor er prognosis for establishing a pregnancy, even after a satisfactory f ertilization rate is achieved.