Cervical Mucus Hostility
The cervical mucus is a jelly-like substance produced by minute glands in the cervical canal. It changes in consistency and composition with the menstrual cycle. Just before ovulation and under the effect of the hormone estrogen it becomes very watery and copious to allow the sperm to swim through it. After ovulation and under the effect of progesterone, the mucus becomes thick and sticky, which render it impenetrable to the sperm. Once the sperm are in the mucus, they can stay there for a few days. Thus the mucus acts as a sperm reservoir.
Cervical mucus hostility is the inability of sperm to penetrate the cervical mucus. The significance of cervical mucus hostility is disputable among infertility specialists. Problems with cervical mucus usually cause no symptoms.
- The mucus is too sticky and thick (and there is not enough of it to allow sperm to swim through). This may be due to poor estrogen stimulation of the cervical glands (e.g. wrong timing of the test or lack of ovulation) or poor functioning cervical glands due to infection or damage caused by surgery, as may occur after cone biopsy.
- Mucus contains antisperm antibodies.
- Abnormal or defective sperm.