We have been trying to conceive for two and a half years. I have been on Clomid (50mg) for five months and Premarin before that. My husband's semen analysis is perfect, and I am ovulating on time (according to my ovulation kit). We are having sex on the night of the LH surge and the next two nights. I have had three postcoital exams that show that my mucus is great, but there isn't any sperm present. Have you ever heard of this happening when the sperm count and mucus are both perfect? Where is the sperm going? My doctor said there is nothing she can do and sees no reason to give me any more medication.

Y.Z.

This situation is one of many that demonstrates the futility of the postcoital test. This test, which involves examining the woman's cervical mucus after sex, has a very low predictive value. That means it is not a good predictor of who will conceive and who won't.

In the past, the postcoital test was a part of my evaluation process for infertility. I remember patients in whom a properly timed postcoital test revealed no sperm present in the mucus. Yet in that very cycle they conceived. Where did the sperm go? Well, one possibility is that the moving sperm quickly entered into the uterine cavity and the fallopian tubes. Recent studies have shed light on this situation. Researchers placed special sperm-sized particles at the top of the vagina and tracked their movement in the body. They found that tiny contractions of the uterus caused a wavelike motion, drawing these particles up to and into the fallopian tube. Surprisingly, most of these particles were actively transferred into the tube leading to the ovary where an egg was growing. So, both swimming action of the sperm as well as uterine transport can effectively clear the sperm from the cervical mucus.

Now, regarding your own situation: If you already ovulate, using clomiphene (Clomid) alone will not likely improve your fertility. In fact, clomiphene use can often adversely effect the cervical mucus. While the use of estrogen (Premarin) may improve cervical mucus, there is little evidence that fertility is actually enhanced by combining clomiphene and Premarin in the face of unexplained infertility. As clomiphene works as an anti-estrogen, giving more estrogen would be counterproductive and merely take you back to where you were before you took the clomiphene.

I would recommend you seek a thorough review of your history by a fellowship-trained reproductive endocrinologist. Ovulation induction combined with intrauterine insemination will likely be recommended.