(See also Overview of Infertility Overview of Infertility Infertility is usually defined as the inability of a couple to achieve a pregnancy after repeated intercourse without contraception for 1 year. Frequent intercourse without birth control usually... read more 
.)
Cervical mucus Uterus and cervix is secreted by glands in the cervix (the lower part of the uterus that opens into the vagina). Normally, this mucus is thick and impenetrable to sperm until just before release of an egg (ovulation). Then, just before ovulation, the mucus becomes clear and elastic (because the level of the hormone estrogen increases). As a result, sperm can move through the mucus into the uterus to the fallopian tubes, where fertilization can take place.
Abnormal mucus may do the following:
Not change at ovulation (usually because of an infection), making pregnancy unlikely
Allow bacteria in the vagina, usually those that cause infection in the cervix (cervicitis Cervicitis Cervicitis is inflammation of the cervix (the lower, narrow part of the uterus that opens into the vagina). It may be caused by an infection or another condition. Cervicitis is often caused... read more ), to enter the uterus, sometimes resulting in the destruction of sperm
Contain antibodies to sperm, which kill sperm before they can reach the egg (a rare problem)
However, problems with cervical mucus rarely impair fertility significantly, except in women who have chronic cervicitis or a cervix that has been narrowed (called cervical stenosis Cervical Stenosis Cervical stenosis is narrowing of the passageway through the cervix (the lower part of the uterus). Cervical stenosis often causes no symptoms. Rarely, the uterus fills with blood or pus. The... read more ) by treatment for a precancerous abnormality of the cervix (cervical dysplasia Cervical Cancer 
).
Diagnosis of Cervical Mucus Problems
A doctor's evaluation
Doctors do a pelvic examination Pelvic Examination For gynecologic care, a woman should choose a health care practitioner with whom she can comfortably discuss sensitive topics, such as sex, birth control, pregnancy, and problems related to... read more to see whether the cervix is narrow and to check for infection.
Treatment of Cervical Mucus Problems
Assisted reproductive techniques
Treatment of infections
Treatment of cervical mucus problems may include placing semen directly in the uterus to bypass the mucus (intrauterine insemination), doing in vitro (test tube) fertilization In vitro (test tube) fertilization (IVF) Assisted reproductive techniques involve manipulating sperm and eggs or embryos in a laboratory (in vitro) with the goal of producing a pregnancy. (See also Overview of Infertility.) If treatment... read more 
, and treating any infections that are identified. Whether using assisted reproductive techniques Assisted Reproductive Techniques Assisted reproductive techniques involve manipulating sperm and eggs or embryos in a laboratory (in vitro) with the goal of producing a pregnancy. (See also Overview of Infertility.) If treatment... read more increases pregnancy rates in women with abnormal cervical mucus is unknown.
