Role of electron microscopy of sperm in the evaluation of male infertility during the era of assisted reproduction

Abstract

Objectives. To determine whether there are indications for and benefits from electron microscopy (EM) of sperm during the era of assisted reproductive technology. Methods. The medical history, semen analyses, and EM findings of 55 patients with pure male-factor infertility were reviewed to determine: (1) which semen characteristics (seminal volume, sperm concentration, percent motility, and percent normal morphology) were associated with normal or abnormal ultrastructure as determined by EM, (2) whether EM findings correlated with success or failure of in vitro fertilization (IVF), and (3) whether EM could screen for potentially inheritable genetic disorders. Results. Principal EM diagnoses were normal sperm ultrastructure (11 of 55; 20%), tail abnormalities (21 of 55; 38%), necrospermia (12 of 55; 22%), acrosomal defects (9 of 55; 16%), neck abnormalities (1 of 55; 2%), and incomplete maturation (1 of 55; 2%). Every patient with an abnormal EM study had impaired motility (33% or below) and abnormal morphology (13% or lower normal forms by World Health Organization criteria). The percentage of normal sperm morphology differed significantly across EM diagnoses ( P < 0.0001). Differences in motility across the groups could not be detected because EM was only performed on patients with impaired motility. Although the partner of 1 patient with a normal EM study who underwent IVF achieved pregnancy, 11 with abnormal EM studies failed to establish a pregnancy by IVF. Finally, 5 (11%) of 44 patients with abnormal EM findings were diagnosed with primary ciliary dyskinesia directly as a result of EM. In addition, 3 (6.8%) of the 44 patients with abnormal EM findings were diagnosed with complete acrosomal loss. Conclusions. Patients with severely abnormal motility and morphology on routine semen analysis may benefit from EM study of sperm. Our data indicate that EM findings correlate with success or failure of IVF, and that EM can screen for potentially inheritable genetic disorders.