Unexplained infertility is a diagnosis of exclusion given to infertile couples who have had a thorough infertility evaluation with no abnormal findings. It is estimated that 15 percent of infertile couples have unexplained infertility. However, some studies suggest that the incidence is much higher than this. The primary reason for inconsistency is that experts disagree about what a complete evaluation really includes.
While the complete evaluation of an infertile couple varies, most experts would agree that a number of steps are standard. A complete history of both members of the couple including a family and genetic history are essential. A physical examination of the woman and a semen analysis from the man are also standard. If the man’s semen analysis is abnormal in any way, it is generally felt that he should be referred to an expert in male infertility for an evaluation and other diagnostic testing that may be indicated.
In addition to a physical examination, the female partner should have an evaluation of her pelvic anatomy, ovulation, and ovarian function. The pelvic anatomy is evaluated by examination, a pelvic ultrasound, and a hysterosalpingogram (HSG). The pelvic ultrasound will allow the doctor to diagnose abnormalities of the uterus such as fibroids or masses in the pelvis or ovaries. In order to evaluate the pelvic anatomy by HSG, a small amount of radio-opaque contrast (dye) is injected through the cervix into the uterine cavity because the uterus and fallopian tubes are not visible on x-ray. Generally this is between 1 and 2 teaspoons of contrast. The pattern seen on the x-ray will allow the physician to infer information about the uterine cavity and fallopian tubes. Usually the doctor will be able to tell whether or not the tubes are open and whether there is a significant abnormality of the uterine cavity. In uncommon circumstances where significant structural defects are found, computerized tomography (CT), or magnetic resonance imaging (MRI) is indicated. However, this is not commonly the case.
Evaluation of ovulation is usually undertaken at the same time as the anatomy is being evaluated. Ovarian testing can include assessment of several hormone levels early in the woman’s cycle. These commonly include follicle stimulating hormone (FSH), estrogen level (estradiol), and anti-mullerian hormone (AMH). Other common tests would include evaluation of thyroid function and prolactin, a hormone that can interfere with ovulation. Ultrasound can often give a sense of ovarian function as well by taking measurements of the ovary and counting small follicles within the ovaries.
When all of these tests are normal, patients are often told they have unexplained infertility. However, there is significant disagreement among physicians as to whether the steps described above truly reflect a complete evaluation. Many physicians feel that the evaluation is not comprehensive without visual diagnosis of the pelvis and the uterine cavity. Laparoscopy is a surgical procedure to evaluate the pelvis. Laparoscopy is performed by passing a surgical telescope through an incision in the naval. This allows the physician to diagnose problems such as pelvic scarring (adhesions) or endometriosis, which are not diagnosable by the other studies described. Laparoscopy is performed in an operating room with the woman under general anesthesia. When abnormalities such as scarring around the tubes are identified, they can usually be treated through the laparoscope at the time of the surgery. Like any surgical procedure, laparoscopy is associated with risks but the incidence of severe complications reported is low, approximately 1 percent. Physicians at University of Colorado Advanced Reproductive Medicine have a rate of significant complications closer to 0.1 percent.
Evaluation of the uterine cavity (hysteroscopy) is usually performed at the same time as laparoscopy. Hysteroscopy is performed by inserting a speculum into the vagina and gently dilating the cervix to about a 1/4 inch (5 millimeter) opening. A small scope is then passed through the cervix into the uterine cavity. This allows the physician to thoroughly evaluate the cavity and rule out the possibility of problems such as uterine fibroids or polyps that might prevent pregnancy. Again, problems that are identified during hysteroscopy can usually be treated at the time of surgery.