Infertility - Distribution and Causes

Infertility is all too common. Studies show that approximately 15% of American couples struggle with infertility. Approximately half of these patients seek treatment, and most significantly, about 85% of this group will conceive with the appropriate medical treatment.

Infertility is typically defined as a condition in which a healthy couple of childbearing age cannot conceive after more than a year of unprotected sexual intercourse. In women over 35 years of age, the time frame may be shortened to six months. Infertility categories are further subdivided into primary infertility - patients without any prior pregnancies, and secondary infertility - couples who are experiencing infertility after having had previous conceptions.

Infertility causes are varied and complex. During the normal fertility process, a sufficient number of normal sperm must be deposited in the vagina at the appropriate time during the menstrual cycle when sperm can penetrate the cervical mucus, ascend through the uterus and fallopian tubes, and fertilize the egg ( male factor infertility ).

The female must produce a healthy, mature egg that is released from the ovary. After release, the egg must travel down the fallopian tube so that the sperm may fertilize it. The fertilized egg then travels into the uterus and implants in the endometrium ( the uterine lining ), which will nourish the embryo's further development.

Infertility may be caused by disruption in any of these processes. Egg development and ovulation are under the control of complex hormonal interactions including FSH, LH, estradiol, progesterone, and others. Diseases of the thyroid, adrenal, pituitary, or hypothalamus glands can lead to ovulatory dysfunction. Certain conditions, such as polycystic ovarian syndrome, cause irregular or absent ovulation that leads to infertility.

Endometriosis

Blockage of the fallopian tubes can occur as a result of serious infection, congenital abnormalities, scarring from previous surgery, or endometriosis. Endometriosis is a major cause of infertility and may be present with no symptoms. Some studies indicate that endometriosis decreases pregnancy rates even though there may be little visible organ damage. Endometrial tissue attaches to organs, grows, divides, and can penetrate causing obstruction and other types of damage. Endometrial tissue is dependent upon estrogen for growth. The medications used to treat endometriosis lower estrogen levels, thus "starving" the aberrant tissue.

Multiple Causes

In many infertility cases, patients may experience more than one of the following conditions. Accordingly, a thorough evaluation of both partners is required. Research suggests that infertility cases fall into these categories:

• Abnormal sperm parameters in as many as 30% - 45% of cases ( male infertility )
• Ovulation and egg quality disorders in approximately 35% of cases
• Pelvic adhesions
• Endometriosis
• Fallopian tube disorders
• Uterine anomalies ( about 25% )
• Combined male and female causes ( 10% )
• Unexplained infertility - causative factors in 10% of infertile couples cannot be identified

IVF or other advanced reproductive technologies are not always the treatments of first choice. Other less extensive treatments are often effective depending on the causal factors. A complete examination and diagnosis is crucial to determine the cause and timely medical treatment to insure a healthy pregnancy.

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