Cervical mucus changes throughout a woman’s cycle. After the menstrual flow has ceased, the cervix begins producing cervical mucus in response to the increasing levels of estrogen. The mucus increases in volume and the texture changes. Estrogen increases until ovulation and the mucus (referred to as fertile mucus) becomes clear, slippery, and stretchy. Once ovulation occurs, the ovary begins producing progesterone, which changes the mucus into a sticky state. Sperm can more easily penetrate the fertile mucus than the mucus that becomes sticky.
The first reported evaluation of sperm and the cervical mucus was performed by J. Marion Sims and later described by Max Huhner. The test became known as the Sims-Huhner test. The purpose of this test was to evaluate the sperm interaction with a woman’s cervical mucus. The test must be done within one to two days before ovulation, when the cervical mucus is abundant and has the qualities of being slippery and stretchy. Basal body temperature charts or ovulation-predicting kits are very helpful in determining the time of ovulation. A couple should abstain from intercourse for 2 days before ovulation, and then have intercourse 2-8 hours prior to the office visit for the PCT. Women are instructed to not use a lubricant during sex and to not douche or take a bath after sex, although taking a shower is permissible.
This PCT test is a quick and painless. Patients undergo a pelvic examination very similar to a Pap smear. A vaginal speculum is inserted into the vagina to visualize the cervix. A catheter with a syringe is used to aspirate the mucus from the cervix. The mucus is placed on a slide and examined under a microscope. The physician evaluates the slide for the presence of active sperm in the mucus. A normal result would be the presence of many moving sperm on the slide. If no sperm are seen or only non-motile sperm are seen, the PCT test is considered to be abnormal. It is felt that a poor PCT may indicate sperm or mucous problems and, possibly, immune factors that could inactivate sperm.
There have been many studies suggesting that the test is neither accurate nor predictive of fertility. With the application of principles of evidenced-based medicine, the role of the PCT has been questioned and its use has become controversial. A classic study by Collins from Canada in 1984 essentially discredited the PCT. Collins reviewed data on couples who had completed their fertility evaluation. These couples were contacted to determine who had become pregnant without any further fertility treatments. He correlated this information with results from their PCT. Patients were compared who had many motile sperm, some motile sperm, few motile sperm, only non-motile sperm, and no sperm in their cervical mucus. The percentage of pregnancies was statistically equal in all of the groups.
Our group has only performed the PCT on a very rare occasion in the last 15-20 years. Since it appears to be of very limited value, we have eliminated the PCT as one of the tests for the basic evaluation of couples having trouble conceiving.