Cervical mucus defect is a slight modification in cervical mucus and may rapidly transform the cervix into a "hostile" environment, which, together with changes in vaginal environment and cervix structure, may prevent natural conception and be a cause of infertility. 

Several hundred glands in the endocervix produce 20–60 mg of cervical mucus a day, increasing to 600 mg around the time of ovulation. It is viscous as it contains large proteins known as mucins. The viscosity and water content varies during the menstrual cycle; mucus is composed of around 93% water, reaching 98% at midcycle. These changes allow it to function either as a barrier or a transport medium to spermatozoa. It contains electrolytes such as calcium, sodium, and potassium; organic components such as glucose, amino acids, and soluble proteins; trace elements including zinc, copper, iron, manganese, and selenium; free fatty acids; enzymes such as amylase; and prostaglandins. Its consistency is determined by the influence of the hormones estrogen and  progesterone. At midcycle around the time of ovulation — a period of high estrogen levels — the mucus is thin and serous to allow sperm to enter the uterus, and is more alkaline and hence more hospitable to sperm. It is also higher in electrolytes, which results in the "ferning" pattern that can be observed in drying mucus under low magnification; as the mucus dries, the salts crystallize, resembling the leaves of a fern.The mucus has stretchy character described as Spinnbarkeit most prominent around the time of ovulation.

At other times in the cycle, the mucus is thick and more acidic due to the effects of progesterone. This "infertile" mucus acts as a barrier to sperm from entering the uterus. Women taking an oral contraceptive pill also have thick mucus from the effects of progesterone. Thick mucus also prevents pathogens from interfering with a nascent pregnancy.

A cervical mucus plug, called the operculum, forms inside the cervical canal during pregnancy. This provides a protective seal for the uterus against the entry of pathogens and against leakage of uterine fluids. The mucus plug is also known to have antibacterial properties. This plug is released as the cervix dilates, either during the first stage of childbirth or shortly before. It is visible as a blood-tinged mucous discharge.

Associated diseases 


Local inflammation causes changes in cervical mucus that can affect sperm and their exit, managing to infertility.

Risk factors 

  • an infection in the lower reproductive tract
  • a poor, acidic diet
  • cervical mucous that is too thick or scanty

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.

The postcoital test (PCT) (also known as Sims test, Huhner test or Sims-Huhner test) is a test in the evaluation of infertility. The test examines interaction between sperm and mucus of the cervix. The PCT is scheduled close to ovulation when mucus is abundant, and the infertile couple is asked to have sexual intercourse, preferably in early hours of morning. Several hours later (usually 2), the woman is examined by the physician. The mucus is aspirated from cervical canal and spread on a glass slide. Smear from posterior fornix is used as control. 10-50 motile sperms per high power field are considered normal. Rotatory or shaky motion of sperms indicates presence of antispermal antibody. Cervical mucus is examined for quality, viscosity and fern test.

Scant, thick, sticky cervical mucus even during ovulation but problems with cervical mucus usually cause no symptoms.

Sometimes, simply changing your diet or growing your water intake may help to improve your cervical mucus.



Surgical therapy 


Other therapies

Estrogen therapy to stimulate production of mucus that aids the sperm in reaching the egg.

Treatment of cervical mucus defect may include placing semen directly in the uterus to bypass the mucus (IUI) and treating any infections that are identified. Pregnancy rate after IUI differ between studies according to patient selection criteria, the presence of various infertility factors, ovarian stimulation methods, number of cycles performed, different sperm parameters and preparation technique. 

If IUI doesn't work, the next stage is to use ICSI (intracytoplasmic sperm injection) and then the best quality embryos are selected and transferred to the woman's womb.

Find more about related issues


Cervix ―sourced from Wikipedia licensed under CC BY-SA 3.0
Cervical Mucus Hostility ―sourced from cvxReproTech licensed under CC BY-SA 3.0
Postcoital test ―sourced from Wikipedia licensed under CC BY-SA 3.0
Fertile Cervical Mucus ―by Almondineverything licensed under CC BY-SA 3.0
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