Infertility: Causes

Until approximately 50 years ago, infertility was thought to be woman's disease. Now, however, it is known that almost half of all infertility problems are due to male factor infertility. The most common causes of female and male factor infertility are discussed below.

Female Factor Infertility - causes of infertility in women usually involve problems with ovulation. Signs of ovulation difficulties include non-existent or irregular menstrual cycles. Birth defects within the uterus and uterine fibroids also cause infertility through miscarriage. In addition, blocked fallopian tubes can cause infertility.

Male Factor Infertility - causes of infertility in men usually involve the production of sperm. One factor that affects sperm production is called varicocele - a condition in which enlarged veins on the scrotum cause temperature abnormalities within the testis, severely limiting the production of sperm. Men who produce no sperm suffer from a condition called azoospermia and men who produce very little sperm suffer from oligospermia. In addition, blocked reproductive tracts, malformed sperm, or non-vigorous sperm can cause infertility.

Causes of Female Infertility

There are several conditions that contribute to female factor infertility, including:

• Abnormal cervical mucus - the cervix produces watery mucus just prior to ovulation that allows the sperm to reach the fallopian tubes and fertilize the egg. If the mucus is too thick it can prevent sperm from fertilizing the egg.
• Abnormal ovulation - hormonal changes are usually the culprit during abnormal ovulation. Any number of factors can contribute to this condition, including premature menopause, polycystic ovarian syndrome (a condition in which an excessive amount of luteinizing hormone causes irregular ovulation), chemotherapy, tumors, infections, heavy exercise or dieting, and hyperprolactinemia (excessive production of prolactin).
• Abnormal uterus - the ability of the uterus to accept implantation of an embryo and nurture it throughout the pregnancy can be affected by several factors, including fibroids, poor endometrial lining, and scarring or inflammation from endometriosis.
• Abnormal pelvic area - abnormalities in the pelvic area such as blocked fallopian tubes or excessive scarring near the pelvic organs can cause infertility. There are a few conditions that contribute to this problem, including pelvic inflammatory disease, endometriosis, and pelvic surgery that results in excessive scar tissue.

Causes of Male Infertility

There are several conditions that contribute to male factor infertility, including:

• Low sperm count (oligospermia) - low sperm count can be caused by a variety of factors, including stress, chemotherapy, high fever, lack of sleep, environmental toxins, over-heating, and other unknown causes.
• Abnormal sperm motility - motility refers to the ability of the sperm to move. If the sperm are slow or if they are unable to move straight forward, they will have difficulty penetrating the egg.
• Abnormal sperm shape - if the shape of the sperm is abnormal (normal shaped sperm should have an oval head and long tail) it will not be able to fertilize the egg.
• Germ-cell aplasia - a condition in which sperm-producing cells develop abnormally.
• Abnormal semen - a decreased amount of semen or semen that does not liquefy properly.
• Tube blockages - blockages of the vas deferens or epididymis can be caused by varicoceles (enlarged veins that restrict the production of sperm in the testicles), gonorrhea, and chlamydia
• Sperm allergy - an immune reaction that produces antibodies that kill the sperm. This can occur in both men and women.