Cervical mucus
Cervical mucus is produced in the cervical canal. Prior to ovulation it becomes very watery, allowing the sperm to swim through. After ovulation the mucus becomes thick and prevents the sperm from swimming through. Once the sperm are in the mucus, they can stay there for a few days. Thus the mucus acts as a sperm reservoir.
This mainly concerns insufficient cervical mucous (CM). The mucous is a necessary part of conception because the sperm are nourished by the CM and also transported by the CM. Another problem that can be determined by examining the CM is when the female is allergic to the male’s sperm and has an allergic reaction to them that actually causes antibodies to be produced that destroy the sperm.
Cervical mucus is a substance secreted within the vagina in response to various hormones within the blood. The characteristics of this substance change in response to reproductive hormones such as oestrogen. Inappropriate changes in the cervical mucus can lead to a hostile environment for the sperm. Cervical mucus incompatibility accounts for approximately 5% of female infertility. A post-coital test is done hours after intercourse and can help assess weather the cause of infertility is related to cervical mucus incompatibility. This test analyses the mucus for volume, consistency, PH and viscosity. If the PH is too acidic as in bacterial and yeast infections, the sperm will die off prematurely. If the cervical mucus is highly viscous then the sperm will have a difficult time penetrating their way to the egg.
Cervical mucus hostility is the inability of sperm to penetrate the cervical mucus, therefore preventing migration through the cervical canal. It may be possible to bypass hostile mucus by intrauterine insemination (IUI).
The cervical glands secrete cervical fluid, which serves as a media for sperm transport. Sperm are deposited in the vagina and swim in the cervical fluid through the cervix and into the uterus. The cervical fluid is rich in nutrients and must have the correct consistency to support sperm transport. If the cervical mucus is too “thick or sticky”, the sperm cannot reach the uterus resulting in infertility.
The cervical mucus must also be free of antisperm antibodies. These antibodies are sometimes mistakenly made by the female’s immune system and can destroy sperm. The antibodies recognize sperm as invading pathogens, such as virus or bacteria, and seek to destroy them. The male may rarely make antibodies to his own sperm, as can be seen with vasectomy reversal.
When female antisperm antibodies are present, or if the cervical mucus is inadequate, intrauterine insemination (IUI) is often the treatment of choice. In IUI, the sperm are washed and concentrated and then placed directly into the uterus using a small catheter, thus avoiding sperm contact with the cervical mucus.
Cervical causes
• Infections
• Hostile mucus
• Hypoplastic cervix
• Cervical anomalies
