Cervical and infertility Factor

The tip of the uterus that extends into the vagina is called the cervix. As a part of natural defense mechanism, during most of the month, thick mucus plugs is there in cervix which does not allow out side foreign matters to enter uterus. Around time of ovulation, because of a rising estrogen levels, the cervical mucus become thinner and thus makes it easier for sperm can enter and swim up into the uterus. After the coitus external os bathe in the seminal pool.

Once sperm are ejaculated into the vagina they must swim through the cervical mucus, pass the cervix, and enter the uterus. Their final destination is the end of the fallopian tube, where fertilization occurs. Abnormalities in the cervical mucus can slow, damage, or destroy sperm.

Some women also have an abnormal narrowing of the cervical opening called cervical stenosis or the cervical canal may be obstructed by a polyp this can also interfere with both infertility testing and procedures. 

Anatomic defects like congenital elongation of the cervix, second degree uterine prolapse and acute retroverted uterus prevents the sperm to enter.  These conditions prevent the external os to bathe in the seminal pool

Few women may have abnormally thick cervical mucus which can make it harder for conception. A test known as a post-coital test (PCT) can be performed within 6 hours of intercourse, just prior to ovulation timings, to see if the mucus is thin and stretchy, and to see if motile sperm are present within the mucus. The presence of motile sperm and normalcy of cervical mucus are the parameters for a normal post-coital test (PCT). 

The post coital test has been the traditional method for identifying cervical factor infertility. It involves collection of a specimen of cervical mucus (by aspiration with a syringe) shortly before the expected time of ovulation and 2 - 4 hours after intercourse. The PCT includes both a gross and microscopic examination to grade mucus characteristics and to assess the number and motility of surviving sperm.

Normal Cervical Mucus:-

1. Ferning - When the cervical mucus dries on a microscope slide, it should take on the appearance of ferns. This assures that the mucus has been exposed to adequate levels of estrogen without any exposure to progesterone.
2. Amount - Cervical mucus production normally increases dramatically just prior to ovulation.
3. Clarity - It should be very clear, almost watery.
4. Cellularity - There should be relatively few cells present, other than sperm.
5. Spinnbarkeit - This is the stretchiness of the cervical mucus. It should be almost elastic and may stretch 10 cms or more.

There is a direct relation between the plasma oestradiol concentration and the individual cervical score

The most common explanation for poor results or a "negative" PCT is improper timing, cervicitis (inflammation of the cervix), previous injury to the endocervical, and treatment with antiestrogens (clomiphene citrate).

Possible explanations for the absence of motile sperm in good quality mucus include ineffective coital technique, failed ejaculation, poor semen quality, and use of coital lubricants that may be toxic to sperm

It is possible that the female produces antibodies to the sperm. The body "mistakes" the sperm for invading pathogens and the immune system produces antibodies to destroy them. This is essentially the same reaction seen when the body’s natural defense mechanism identifies a foreign bacteria or virus.

Results of the post-coital test- PCT can be correlated for successful treatment of infertility. PCT can also be judge as parameter for success in treatment of infertility. In women having an abnormal PCT, the sperm are then unable to penetrate the mucus and can have failure of treatment of infertility. An abnormal PCT with proper timing should be repeated to be corrected and have a normal one for successful outcome.