NYU Langone urologists who specialize in male infertility work together with female reproduction specialists to diagnose and manage infertility in couples. About 15 percent of couples trying to conceive are unable to do so within a year, and male infertility can be a contributing factor for about half of them.
For a pregnancy to occur, a man’s sperm, which is the male reproductive cell, must fertilize a woman’s egg. The fertilized egg forms an embryo that implants into the wall of the woman’s uterus.
Sperm is produced in the testicles and stored in the epididymis—the ducts behind the testicles—before it travels through the vas deferens and then the penis during ejaculation. Problems with any part of this process can lead to infertility. This can include problems with hormones, problems with sperm production, obstruction in the ducts, and genetic abnormalities.
The causes of male infertility are broadly classified as obstructive or nonobstructive. In obstructive infertility, sperm is blocked from exiting the penis during ejaculation. In nonobstructive infertility, there may be a problem with sperm production or quality or with its ability to fertilize an egg.
A total absence of sperm is the cause of infertility in about 10 to 15 percent of infertile men. This is called azoospermia, and it can be caused by a genetic irregularity, hormone imbalance, or blockage in the tubes that carry sperm to the urethra.
The causes of obstructive male infertility may include retrograde ejaculation, which is when semen enters the bladder rather than being ejaculated from the penis. Infections, including those due to sexually transmitted diseases, may also be a cause. Sometimes, surgery for conditions such as hernia or prostate cancer may cause scar tissue that causes blockages. Inherited genetic conditions, such as cystic fibrosis, can also cause an obstruction that leads to male infertility.
Causes of nonobstructive male infertility include varicocele, which is when the veins in the testicles enlarge, reducing the sperm count and quality. Varicocele occurs when one-way valves in the veins along the spermatic cord, which supports the testicles, don’t open and close properly, causing blood to back up. This leads to a swelling of the veins, similar to varicose veins in the legs. In most men, this causes no symptoms, although pain or heaviness in the scrotum can occur.
Doctors can diagnose varicocele by performing a physical examination. Your doctor may recommend an ultrasound for further evaluation of the size of the varicocele.
Other nonobstructive causes include hormone imbalances, such as low testosterone; erectile dysfunction; and certain medications, such as anabolic steroids, which reduce sperm production.
Langone urologist asks about your medical history and performs a physical examination. Sometimes, he or she also requests that certain tests be performed.
To determine the cause of infertility and choose the treatment or treatments that best suit your needs, your NYU Langone urologist asks about your medical history and performs a physical examination. Sometimes, he or she also requests that certain tests be performed.
NYU Langone urologists may test a man’s semen to determine causes of infertility. Doctors examine semen volume, as well as the number of sperm, their shape, and their motility, or movement. A semen sample can be provided in a cup at the NYU Langone Fertility Center or NYU Langone Reproductive Specialists of New York, or another laboratory of your choice.
Blood tests can identify a man’s levels of the reproductive hormone testosterone and other related hormones. Hormone imbalances can lead to low sperm counts, cause erectile dysfunction, and lower sex drive.
You may be asked to provide a sample of your urine after ejaculation. Doctors check the urine for the presence of sperm, which can occur as a result of retrograde ejaculation.
Doctors use transrectal ultrasound to detect blockages in the tubes that carry semen out of the body or problems with the prostate, such as benign prostatic hyperplasia, in which the prostate becomes enlarged. During an ultrasound, sound waves produce images that allow doctors to visualize the reproductive organs.
Doctors may perform blood tests to detect genetic causes of infertility. These tests include chromosome analysis and evaluation of the male sex chromosome, known as the Y chromosome, which can determine if genetic information is altered or missing, thereby affecting sperm production.
Genetic conditions that can affect male fertility include Klinefelter Syndrome, which results when a male infant is born with an abnormal number of sex chromosomes, causing few or no sperm to be produced.
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