Unexplained infertility is the inability to conceive or carry a pregnancy following one year of unprotected intercourse when the infertility evaluation is completely negative. About 10 to 20 percent of infertile couples are diagnosed as having unexplained infertility. It doesn’t mean that there is no reason for the infertility, just that the reason is unidentified at that time and standard infertility testing has not found a cause for the failure to conceive.
Unexplained infertility is frustrating for patients and medical caregivers alike. The data suggest that with appropriate treatment, at least 80 percent of patients with unexplained infertility eventually conceive.
Causes of Infertility
In reality, there are probably hundreds of “causes” of infertility. For example, the egg may not be released at the optimum time for fertilization, it may not enter the fallopian tube, sperm may not be able to reach the egg, fertilization may fail to occur, transport of the fertilized egg may be disturbed, or implantation fails.
There are hundreds of molecular and biochemical events that have to happen perfectly in order to have a pregnancy develop. Standard tests for infertility, such as blocked tubes, abnormal sperm count, ovulation problems do not address the molecular issues. Read more about the conditions required for conception (link to section below, “Conception 101).
Unexplained infertility and female age. Women of advanced maternal age have eggs of reduced capacity for normal and successful fertilization. The reason for this is that there are more likely to be egg quantity and quality problems as women age. The older the female partner, the more likely that there is an egg related issue causing the fertility problem. Unfortunately, there is currently no specific test for “egg quality.” The likelihood of a diagnosis of unexplained infertility is greater in women 35 and over, and higher in women over 38. Many women over 40 who try to get pregnant will have difficulty, and fertility over age 44 is rare, even in women who are ovulating regularly every month.
Mild endometriosis. Some experts consider infertility associated with mild endometriosis to be in the “unexplained” category. A cause and effect relationship between mild endometriosis and fertility problems has not been firmly established.
Duration. The duration of infertility is important. The longer the period of infertility, the less likely the couple is to conceive on their own. After five years of infertility, a couple with unexplained infertility has less than a 10 percent chance for success on their own.
What Are Treatment Options for Unexplained Infertility?
Assisted reproductive technologies such as Intrauterine Insemination (IUI), also called artificial insemination, and In-vitro Fertilization (IVF) have high success rates for women who have unexplained infertility. Typically, women under 40 will try about three artificial inseminations and if they do not become pregnant, use IVF.