Unexplained Infertility

For a significant number of infertile couples, even the experts don’t know why they can't get pregnant. Can new tests help diagnose unexplained infertility?

Sound hard to believe? Despite all the super science, all the headlines extolling new tests and new pregnancy options, unexplained infertility is still very much a reality. Some couples may simply be achingly slow to conceive, or have problems that are so subtle that scientists aren’t even aware of them yet or that don’t show up on current tests. While precise numbers are hard to come by, unexplained infertility affects roughly 15 percent of all infertile couples—and are two of the most difficult words to hear and to accept.

“Couples want to know why they’re not getting pregnant. Doctors are also trained to make a specific diagnosis. It’s incredibly stressful for everyone involved,” admits Nanette Santoro, M.D., professor and director of reproductive endocrinology and infertility, Albert Einstein College of Medicine, New York City. “Unfortunately,” she adds, “this emotional reality can lead to use of medically available but meaningless tests along with questionable practices that take advantage of couples who feel incredibly vulnerable.”

Unexplained Infertility: A Problem Without a Cause?

“Unexplained infertility” is defined as the inability to achieve pregnancy after one year of regular unprotected intercourse despite no apparent medical cause. It’s a diagnosis of exclusion, to be made only after accepted fertility check-ups and testing have been completed for a woman and a man. It sounds straightforward, but consider this: almost every word of the definition can be interpreted differently.

“At a very basic level, defining infertility has always hinged on a couple’s having ‘regular unprotected intercourse at the optimum time.’ But let’s face it; no one really knows just how many people in any given population are trying to get pregnant. It’s very difficult to get at this kind of information precisely,” acknowledges Phyllis C. Leppert, M.D., Ph.D., chief of the reproductive services branch of the National Institute of Child Health and Human Development, National Institutes of Health. What’s more, human reproduction is, as one expert put it, maddeningly inefficient: Even the most fertile young woman paired with an equally fertile young man has only a 20 to 30 percent chance of getting pregnant in any given month.

And just what constitutes a proper fertility workup? It starts with complete physicals for the woman and man, as well as thorough reviews of both partners’ medical and sexual histories. After that, it should always include the following four types of tests:
- For the man, a semen analysis to measure the amount, movement, appearance and shape of sperm (two are generally recommended over 2-6 months);
- For the woman, a hysterosalpingogram (HSG), or special x-ray of the fallopian tubes and uterus to check that her tubes are ‘clear’ (not blocked by scar tissue, for instance);
- Also for her, an assessment of ovulation, either by using a home ovulation kit, tracking basal body temperature, using a more extensive home monitoring device provided by the doctor, or having a blood progesterone test done in the doctor’s office;
- Finally, another test for women: a day-3 FSH (follicle stimulating hormone) test to rule out low ovarian reserve (especially if a woman is over 35). “Based upon the physician’s suspicion, it may be reasonable to also check a woman for some mild hormonal problems that could impact fertility by doing a thyroid test panel or a blood prolactin test,” says Dr. Santoro. Other doctors routinely check for chlamydia antibodies as a screen for prior pelvic infections that could decrease fertility.