January 24, 2018

Most infertility is unexplained

A lot of people ask me about unexplained infertility. Well, allow me to explain the unexplainable in very practical terms. If you have gotten pregnant and now have a baby, you are obviously not infertile, so this would not pertain to you. On the other hand, if you’ve been trying for some time, but are still not pregnant, then obviously you are not happy about the situation. I don’t want to restrict the definition of the word infertility with a set time frame, because it differs for each individual. Some people are sad and miserable if they are not pregnant after four months. Others will patiently keep trying beyond three years without any intention of asking for help. So, let’s just say if you are not pregnant yet and you want to be and you have been having unprotected sex for at least six months, then this will be of interest to you.

Prior to any sort of investigation, all infertility is unexplained. After a proper infertility workup, MOST infertility is still unexplained. I will repeat this, modifying it a bit because it goes against what you may have read elsewhere. Repeat. After a proper infertility workup, MOST infertility is still somewhat technically unexplained. Why? It’s like this. When you have finished doing testing for infertility, there are three basic scenarios you could reach. One is the OBVIOUS PROBLEM SCENARIO. This means our testing has unearthed an obvious red-flag big problem. Under these circumstances, couples have essentially zero chance of getting pregnant without medical help. Examples of this include someone whose tubes are both blocked, or who has a husband with zero sperm or someone whose ovaries have completely shut down into premature menopause. If any of these conditions are found, then your search is over and you will have to directly address these issues, because you’re not going to have a baby without medical help.

The second scenario is the EVERYTHING NORMAL SCENARIO. In this case, everything that you have tested, and I’m talking about the basics of a semen analysis, HSG and documentation of ovulation, comes back normal, or even above-average. This is what is classically referred to an unexplained infertility. It means everything looks fine on paper, but yet you are still not getting pregnant. Very frustrating.

The third scenario that is found in reality every day, but is not classically defined by medical textbooks is the SUBOPTIMAL FINDINGS SCENARIO. In these cases, there are found to be one or more things that are not quite perfect, but yet are not bad enough to sentence you to zero chance of conception. These include things like a low (but not zero) sperm count, one-sided tubal blockage with the other side open, surgically-documented scar tissue or endometriosis or evidence of inconsistent, but not absolutely absent, ovulation, or just advanced ovarian age whether chronologically (you really ARE 36) or biologically (you are 26 but your ovaries act 36).

Sometimes, a patient comes to me feeling like they know their diagnosis. “Doctor, we have already been checked out by our OB and we now that the problem is my husband’s sperm”. For example, this might be said to me by a couple for whom the semen analysis shows a 13 million / cc count with 39% motility. This is certainly below average and even in the abnormal range according to set criteria. However, if you went to every first-grade class in the country, hunted down the biological father of every healthy child and subjected these fathers to a semen analysis, I would bet that you would find not one, but many samples which have counts less than 13 million. As an additional example, if you did an HSG on every mother, you would find quite a few who have one blocked tube. So basically, in these situations, you have found something, but it’s not necessarily enough to explain the infertility, because it can’t pass the litmus-test question “Can other people with this condition ever get pregnant?” By the way, having said that, in very rare cases, even couples in the first scenario, the OBVIOUS PROBLEM SCENARIO, have been reported to get pregnant. How can a woman with two blocked tubes get pregnant? One theory is that the test was a false positive, like perhaps her tubes went into spasm at the time of the HSG and showed up blocked when in reality there was still a tiny tiny passageway or perhaps the films were misread by the radiologist or perhaps a clerical error led to the report of someone else’s test under her name. You get the point. These situations are extremely rare, but not entirely impossible.

So as many of you know by now, my way of thinking is always focused on solutions, decisions and actions, so while it’s a fascinating intellectual exercise to discuss these definitions and scenarios, the key question is what do we do about it? In the first scenario, the OBVIOUS PROBLEM SCENARIO, you would directly address the obvious problem. Duh. Depending on which problem, some solutions would include IVF, sperm donation, egg donation or attempted sperm extraction.

For the couples in the SUBOPTIMAL FINDINGS and EVERYTHING NORMAL scenarios, there is overlap in the treatment options. The focus becomes more of a shotgun strategy, meaning we can just try to universally give everything a boost. Get some improved egg quality and quantity (ovulation medications). Send the sperm closer to the egg and with perfect timing (IUI). Minimize uncertainty by physically putting the eggs and sperm together in the laboratory (IVF). We do this even if that’s not the suspected problem. So we give fertility medications to a couple with low sperm, in the hopes that more eggs will make up for fewer sperm. It’s like a football team with a terrible defense signing a top free-agent QB and RB and WR to try and overcompensate for the shortcomings on the other side of the ball.

The choice of which strategy depends on many factors including medical ones (test results, past treatment and response history) and non-medical ones (financial choices, personal attitude towards medical treatment, sense of urgency). We will address the important issue of how to approach unexplained infertility in future posts. But just remember the take-home message. In a strict sense, MOST infertility is unexplained.