(See also Overview of Infertility Overview of Infertility Infertility is usually defined as the inability to conceive after 1 year of regular, unprotected sexual intercourse. Infertility is defined as a disease by the World Health Organization (WHO)... read more .)
Normally, cervical mucus is stimulated to change from thick and impenetrable to thin and stretchable by an increase in estradiol levels during the follicular phase of the menstrual cycle Menstrual Cycle Hormonal interaction between the hypothalamus, anterior pituitary gland, and ovaries regulates the female reproductive system. The hypothalamus secretes a small peptide, gonadotropin-releasing... read more .
Abnormal cervical mucus may
Remain impenetrable to sperm around the time of ovulation
Promote sperm destruction by facilitating influx of vaginal bacteria (eg, due to cervicitis)
Contain antibodies to sperm (rarely)
Abnormal mucus rarely impairs fertility significantly, except in women with chronic cervicitis Cervicitis Cervicitis is infectious or noninfectious inflammation of the cervix. Findings may include vaginal discharge, vaginal bleeding, and cervical erythema and friability. Women are tested for infectious... read more 
or cervical stenosis Cervical Stenosis Cervical stenosis is stricture of the internal cervical os. Cervical stenosis may be congenital or acquired. The most common acquired causes of cervical stenosis are Menopause Cervical surgery... read more due to prior treatment for cervical intraepithelial neoplasia.
Diagnosis of Abnormal Cervical Mucus
Examination to check for cervicitis and cervical stenosis
A pelvic examination is done to check for cervicitis and cervical stenosis. If cervicitis is suspected because women have cervical exudate (purulent or mucopurulent) or cervical friability, a cervical swab is done to test for gonorrhea and chlamydial infection. Complete cervical stenosis is diagnosed if a 1- to 2-mm diameter probe cannot be passed into the uterine cavity.
Postcoital testing of cervical mucus to determine whether viable sperm are present (which used to be routine during infertility evaluation) is no longer considered useful because results do not correlate with subsequent pregnancy rates.
Treatment of Abnormal Cervical Mucus
Antibiotics, if cervicitis is present
Sometimes cervical dilation for cervical stenosis
Sometimes intrauterine insemination or in vitro fertilization
Treatment may include intrauterine insemination and in vitro fertilization In vitro fertilization (IVF) Assisted reproductive techniques (ARTs) involve manipulation of sperm and ova or embryos in vitro with the goal of producing a pregnancy. For assisted reproductive techniques, oocytes and sperm... read more 
. However, whether either treatment is effective in women with abnormal cervical mucus is unproved.
There is no evidence that using drugs to thin the mucus (eg, guaifenesin) improves fertility.
Key Points
Abnormal cervical mucus rarely impairs fertility significantly, except in women with chronic cervicitis Cervicitis Cervicitis is infectious or noninfectious inflammation of the cervix. Findings may include vaginal discharge, vaginal bleeding, and cervical erythema and friability. Women are tested for infectious... read more
or cervical stenosis Cervical Stenosis Cervical stenosis is stricture of the internal cervical os. Cervical stenosis may be congenital or acquired. The most common acquired causes of cervical stenosis are Menopause Cervical surgery... read more .Do a pelvic examination to check for cervicitis and cervical stenosis.
Postcoital testing of cervical mucus is not useful.
Consider intrauterine insemination and in vitro fertilization, but whether either results in pregnancy when cervical mucus is abnormal is unproved.
