Abnormal shape and movement of sperm will prevent the sperm to quickly and accurately reach or penetrate the egg. Causes include:
a) Infections:Active bacterial or viral infections may have a negative effect on sperm production or sperm function. Sexually transmitted diseases ( STD’s) and mumps, or inflammation of the testicles, prostate, urethra, or epididymis can temporarily or permanently affect movement/motility of the sperm. White blood cells, which are the body’s response to infection, may also have a negative effect on sperm membranes making them less hearty.
b) Anti-sperm antibodies:Triggered by a man's immunologic response to his own sperm, antibodies are usually the product of injury, surgery or infection. In attacking the sperm, they prevent normal movement and function of the sperm. making it more difficult for sperm to swim to the uterus and penetrate eggs.