The sperm deformity index: a reliable predictor of the outcome of oocyte fertilization in vitro.
OBJECTIVE
To evaluate a novel expression of sperm morphological parameters, the sperm deformity index, as a predictor of fertilization in vitro.


METHODS
Prospective blind clinical trial.


METHODS
Academic tertiary referral center.


METHODS
Detailed sperm morphological assessment applying strict morphological criteria and a multiple entry technique for an unselected male population undergoing IVF. The sperm deformity index, defined as the average number of deformities per sperm assessed, was calculated.


METHODS
One hundred fifty-eight patients undergoing IVF treatment. Females with conditions negatively influencing fertilization were excluded.


METHODS
Fertilization rates and pregnancy.


RESULTS
Seventy-three percent of patients achieved fertilization. Patients achieving fertilization had a significantly higher median proportion of normal forms and a significantly lower median sperm deformity index than the nonfertilizers. The receiver operator characteristic (ROC) curves identified cutoff points that maximized the sum of sensitivity and specificity at sperm deformity index 1.6 and normal forms 4%. The sperm deformity index had a greater sensitivity (96%), specificity (72%), positive predictive value (90%), and negative predictive value (86%) than the proportion of normal sperm morphology (87%, 69%, 89%, 66%, respectively) at the optimal cutoff points. The area under the ROC curve was greater for the sperm deformity index (0.875) than for the proportion of normal sperm morphology (0.622). Achieving pregnancy did not correlated with sperm morphology.


CONCLUSIONS
The sperm deformity index is a more reliable predictor of the outcome of fertilization in vitro than the proportion of normal sperm morphology and can assist to identify patients who require techniques such as intracytoplasmic sperm injection.
Aziz
N
N
University of Liverpool, United Kingdom.
Buchan
I
I
Taylor
C
C
Kingsland
C R
CR
Lewis-Jones
I
I
D000328:Adult; D004311:Double-Blind Method; D005260:Female; D005306:Fertilization; D005307:Fertilization in Vitro; D005544:Forecasting; D006801:Humans; D008297:Male; D009865:Oocytes / Q000502:physiology*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D012016:Reference Values; D013076:Sperm Count; D013081:Sperm Motility; D013094:Spermatozoa / Q000002:abnormalities* / Q000166:cytology / Q000502:physiology; D016896:Treatment Outcome