Infertility Evaluation & Establish a Diagnosis
Establish a Diagnosis
The normal menstrual cycle is a repetitive process, which might be viewed as "reproductive failure." As the normal physiologic intention of the menstrual cycle is to result in a pregnancy each and every time it occurs, menstrual bleeding might be viewed as failure of this process. The hallmarks of the menstrual cycle include a dynamic coordination of the hypothalamic-pituitary-ovarian-endometrial axes, culminating in the release of a mature oocyte.
This mature oocyte must be successfully retrieved by the fimbriated end of the fallopian tube and made available for fertilization. In an independent process, sperm placed in the vagina at the time of intercourse must successfully survive the hostile environment of the vagina, enter the favorable confines of the cervical mucus, and ultimately work themselves into the upper genital tract. The head of each sperm contains specific binding sites for the outer layer of the egg (zona pellucida). Once the sperm has bound to the zona pellucida then the fertilization process can occur. After ovulation, the egg lives for approximately 24 hours and the sperm live for about 72 hours. Therefore, intercourse every other day around the mid- cycle should successfully result in a condition in which fertilization can be maximized. Realizing the intricacies of this system, the normal fertility curve can be appreciated.
Cycle fecundity is a term used to describe the likelihood of a pregnancy occurring with each individual menstrual cycle. The human is a relatively inefficient reproducer and, in fact, the cycle fecundity is approximately 22% percent. If one views this fertility curve over time, successful reproduction is a result of repetitive attempts at this intricate fertilization process. Realizing and keeping in perspective the normal fecundity curve can allow patients and physicians to embark on fertility treatments with realistic expectations.
The infertility evaluation consists of a variety of tests to document normal sperm, normal ovulation, fallopian tubal patency, normal endometrial environment, and a normal pelvis. There are multiple, controversial tests that have been proposed to evaluate the reproductive condition and identify particular pathologic disorders. Tests that fall into this controversial category including the following: post-coital test, late luteal phase endometrial biopsy, antisperm antibody determinations, hamster egg penetration tests, and serial ultrasounds to determine the luteinized-unruptured-follicle syndrome. All these controversial tests have relatively poor sensitivity and specificity and, as a result, are fraught with false negatives and false positives. Use of these tests, therefore, should be approached with caution. Certainly many pregnancies have resulted in couples in whom antisperm antibodies have been identified as well as 0 percent hamster egg penetrations.
The diagnosis of "unexplained infertility" then becomes a diagnosis of exclusion. It reflects our lack of understanding of the reproductive process and includes couples that are normal as well as couples who may have subtle defects in the reproductive process. The treatments for unexplained infertility place a couple in a relatively favorable prognostic category. When viewed with other common causes of infertility, unexplained infertility often results in either treatment-dependent or treatment-independent success.