What is a Huhner test?

The Huhner test is a type of fertility test in which the compatibility of sperm and cervical mucus is evaluated. This is an important test because up to 8% of infertility cases are related to incompatibility between cervical mucus and sperm. The Huhner test, also known as the Sims-Huhner test or the postcoital test, is performed by an infertility diagnostician, who tests these fluids several hours after intercourse.

The cervical cells secrete mucus that changes in consistency according to the different phases of the menstrual cycle. As the cycle approaches the time of ovulation, the cervical cells produce large amounts of mucus. The mucus also changes qualitatively, to approach a pH and viscosity more compatible with sperm migration. In order for sperm to pass from the cervix to the uterus, the mucus present in the cervix must generally have a pH of 7 to 8.5 and have a certain degree of stickiness and stretch. Infertility can occur if the cervical mucus and sperm are incompatible.

To determine if the cervical mucus has the required pH and viscosity, the Huhner test is performed several hours after intercourse, around the time of a woman's ovulation. Generally, a couple undergoing testing is asked to avoid sexual intercourse for 48 hours before the test, and then to have sexual intercourse four to eight hours before the test appointment is scheduled. During the testing appointment, mucus samples are collected from the woman's cervix and then examined in a diagnostic laboratory.

Several different aspects of cervical mucus are evaluated during a Huhner test. First, the mucus is examined for clarity and stickiness. The mucus obtained from the cervix at the time of ovulation should be clear and watery, and viscous enough that a portion of the mucus can stretch at least 8 cm (3.15 inches) before it breaks. The pH of the mucus is also recorded; The optimum level is pH 7 to 8.5.

The next part of the Huhner test involves microscopic examination of the mucus to check how many sperm are present. A drop of mucus must contain a dozen or more sperm, which must swim with a strong forward motion. If there are too few sperm, this may indicate that the pH of the mucus is too low for sperm to survive. If the sperm can't swim hard, the mucus may be too thick.

The presence of other cell types, including immune cells and yeast cells, is also seen. If there are a higher number of immune cells than normal, an infection may be affecting the quality of the cervical mucus. Similarly, the presence of yeast cells indicates an infection that can also affect sperm survival and motility. In some cases, resolving the infection will improve the quality of the mucus enough to allow the woman to conceive.

If the quality of a woman's cervical mucus is reducing her ability to conceive, and this problem has no other underlying cause, she may be prescribed hormonal medications that can improve the quality of the mucus. When medication does not resolve the problem, artificial insemination may be recommended. This procedure allows the sperm to bypass the cervical mucus, improving the chances of conception.

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