I read your article concerning cervical mucus with respect to fertility. I was surprised to read that you consider it a poor predictor of fertility. I have read many articles written by researchers that indicate exactly the opposite. Many claim that "fertile" mucus is a necessity in order for the sperm to make it to the egg. Do you consider this research to be flawed in some way? Dr. Erik Odeblad from Sweden is one of the doctors I am aware of who has done some of this research.

Donna

From my position as a doctor, I need to consider how I would assess the quality of the mucus, and what I would do with the results of any test. One conventional approach is a postcoital test (PCT). But there are no studies that use appropriate statistical methodology that show that using the PCT during infertility treatment improves results. There are also no studies that use appropriate statistical measures to test various ways of doing the PCT. By this I mean that the specific methodology (e.g. how long from intercourse to check, when in the cycle to perform the test, how to collect mucus) and the criteria for determining normal results (e.g. how many total sperm, percent that are moving, total number moving, number of white blood cells, presence of shaking sperm) have not been standardized. A PCT by one researcher may not be the same as another researcher.

For a medical test to be of value it must meet certain criteria. First, it must have sensitivity and good specificity. That means it must do a good job picking out all those couples who have a fertility problem due to poor mucus, while not labeling couples as having a problem where none exists. Most older PCT studies only look at infertile women; they do not look at normal fertile women. When both fertile and infertile women are checked, we again find that the PCT offers little help in predicting who will conceive and who will fail. Since many women with poor PCT results conceive, I am not sure that "bad mucus" is a fertility problem.

The next consideration is whether the test provides information on how to best treat your fertility problem. Again, PCT fails in this regard. Let's look at this a bit closer. If I suspect an infection, I will perform a culture and tailor the treatment according to the results. If the test shows you have an infection, I can treat it with an antibiotic, and the test also indicates which antibiotic to choose. PCT does not work like this. If the PCT is abnormal, the recommended treatment would be intrauterine insemination (IUI). There are no well-designed studies (randomized and controlled) that show any improvement in monthly pregnancy rates by using such approaches as cough syrup, low-dose estrogen or cervical insemination, so it looks like the IUI is our only option. And what if the test is normal? Assuming all other factors are normal, we call the problem "unexplained infertility," and again the appropriate approach is IUI, which has been shown in well-designed studies to improve monthly conception rates in cases of unexplained fertility. So, spending time and money on the PCT does not change the recommendation I would make to help you conceive.

The use of evidence-based medicine is helping us review the quality of medical research and the impact of testing and treatment on patients' success. Unfortunately, much of what we previously considered "standard of care" does not meet the statistical criteria to be considered medically useful or effective in light of newer statistical methods.