The relationship between sperm ultrastructural features and fertilizing capacity in vitro.
OBJECTIVE
To evaluate the relationship between ultramorphological features of the human sperm and its fertilizing capacity in vitro.


METHODS
The study was performed retrospectively. Ultrastructural features were assessed using scanning and transmission electron microscopes in sperm samples of individuals who underwent an in vitro fertilization (IVF) treatment cycle no more than 6 months before the study.


METHODS
Institutional clinical care.


METHODS
Fifty-six infertile couples in whom mechanical infertility was diagnosed in the female partner. Patients were categorized as fertilizing when fertilization of at least 30% of the oocytes occurred (n = 27) and nonfertilizing when none of the oocytes fertilized in at least two consecutive IVF treatment cycles (n = 29).


RESULTS
The two groups differed significantly only in ultramorphological parameters of the sperm head and acrosome (head, F(8,36) = 2.8, P less than 0.02; acrosome, F(4,40) = 2.8, P less than 0.04), and especially in the following malformation patterns: hyperelongated head, acrosome deficiency, and acrosome damage. The suggested score based on these findings was able to predict 90% and 76% of the cases with and without fertilizing potential, respectively.


CONCLUSIONS
The ultrastructural morphology of the sperm head components is a key parameter for assessing the sperm fertilizing capacity in vitro.
Mashiach
R
R
Department of Obstetrics and Gynecology, Beilinson Medical Center, Sackler School of Medicine, Tel Aviv University, Petah Tikva, Israel.
Fisch
B
B
Eltes
F
F
Tadir
Y
Y
Ovadia
J
J
Bartoov
B
B
D000328:Adult; D000704:Analysis of Variance; D016002:Discriminant Analysis; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008297:Male; D008854:Microscopy, Electron; D013094:Spermatozoa / Q000502:physiology / Q000648:ultrastructure*