The cervix is the opening between the vagina and the uterus.
Cervix is lined by cervical glands, these glands produce mucus.
Once sperm are ejaculated they swim through this mucus from the vagina through the cervix and into the uterus. The mucus also provides nourishment for the sperm. If the cervical mucus is inadequate, the sperm cannot reach and fertilize the egg.
Estrogen stimulates the production of cervical mucus and low levels of this hormone can lead to diminished or thickened cervical mucus which inhibits sperm transport.
How cervix can be the cause for infertility:
Consistency of cervical mucus plays major role in sperm transport. Thin cervical mucus can assist sperms to swim up inside the uterus after intercourse and Thick or less cervical mucus will hamper the sperm movements.
In fertile period when the follicle has ruptured and egg is released cervical mucus present in the cervix is thin slimy and in more quantity, so if intercourse takes place the semen deposited on cervix, sperms directly can swim up inside uterus.
Some drugs given for fertility treatment can deteriorate the cervical mucus quality, making cervical mucus thick and hostile for sperms.
Infection at the cervix also may cause bad quality of cervical mucus.
Sometimes cervical mucus may have anti sperm antibodies. These anti sperm antibodies sense the sperms as foreign body and destroy them, either by formation of large clumps-agglutination or make them immobile.
Anatomical defects/growths at the level of cervix may be responsible for the mechanical obstruction for the sperms to swim up inside uterus.
How to diagnose cervical factors of infertility:
1. Generally when we do the genital examination of the patient, we directly see the cervix and can visually inspect if there is any infection, cervical erosion, any growth at the cervix, quality of the cervical mucus etc.
2. The post coital (after intercourse) test is used to determine the ability of sperm to survive in the cervical mucus. During post coital test a sample of the mucus is obtained after intercourse and examined under a microscope. If numerous dead or immobile sperm are seen it indicates a possible antigen/antibody reaction. Now-a-days Post coital test is not done frequently.
3. Transvaginal ultrasound may diagnose anatomical defects/ growths at the cervical level.
Treatment for the cervical factors of infertility:
1. Anatomical defect/grow can be surgically removed or corrected.
2. Treatment of the existing infection may help if the infection is the main culprit.
3. When cervical factor infertility is diagnosed such as bad mucus anti sperm antibodies the first line treatment is usually intrauterine insemination (IUI). In an IUI cycle, the sperm are collected by masturbation, concentrated, washed and specially prepared, and inserted directly into the uterus using a small catheter. Unwashed sperm can cause very serious allergic reactions and should never be placed in the uterus. IUI bypasses the cervical mucus insuring that the sperm reach the uterus.
4. If three to six cycles of stimulated (using injectable FSH) IUI fail, in vitro fertilization is usually the next treatment option.