The Cervical Factor
from the book How to Have a Baby:
by Dr. Aniruddha Malpani, MD and Dr. Anjali Malpani, MD.
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Normal cervical mucus
Cervical mucus is a jelly-like substance produced by tiny glands in the
cervix called cervical crypts. It has a protective function and may prevent
bacteria from getting into the uterine cavity. The mucus changes predictably and
cyclically during the menstrual cycle. During the first half of the cycle before
ovulation, when the hormone estrogen is produced in ever increasing amounts, the
mucus made by the cervical glands becomes watery and copious. Sperm can
penetrate the watery mucus easily, and when intercourse takes place, they swim
through it into the uterus.
After ovulation the quality of the mucus changes because the corpus luteum of
the ovary now starts to make the hormone progesterone. Mucus produced under the
influence of progesterone is thicker, stickier and its quantity is reduced.
Sperm cannot swim through this mucus, and it forms a barrier to sperm entry into
the uterine cavity.
Even if intercourse occurs at the time the cervical mucus is at its most
favourable, only about 1 in every 2000 sperm enter the mucus. The rest of the
sperm remain in the vagina, where they die, because of the acidic pH of the
vagina. Those sperm that have entered the mucus can survive there for long
periods - certainly for several days after intercourse. Once in the cervical
mucus, they steadily swim upwards from it into the uterus over a period of 48 to
72 hours. Thus the cervical mucus acts as a sperm reservoir, to be banked on if
intercourse does not take place at ovulation. This is why you donít need to
have sex everyday in order to conceive! The cervical mucus also acts as a filter
- and allows only the best sperm to swim through it into the uterus and up
towards the egg present in the fallopian tube.
Observing the mucus
Mucus flows from the cervix down the walls of the vagina and can be observed
when it reaches the vulva. You can learn to observe the changes in your mucus by
becoming aware of the wet, lubricative feeling produced by the mucus, and by
observing the mucus itself at the vulva. This is called the Billing (fertility
awareness) method, and is very useful in allowing you to determine when you
You need to chart what the mucus looks like and feels like daily, from the
day your bleeding stops. You will find the mucus present at your vaginal opening
- the vulva. Remember, you do not need to feel inside the vagina; this will
simply confuse the picture, because the vagina is always moist. It is the vulva
which is the mucus (fertility) monitor.
In a typical 28 days menstrual cycle, at the end of bleeding, the sensation
you experience is one of dryness and no mucus is seen or felt. In some women,
there is some mucus, but it is thick, sticky, and scanty. This is the basic
infertile pattern of dryness and lasts for two to three days. Once this is over,
you may notice a feeling of moistness at the vulva and the mucus will change in
appearance and feel. It becomes thinner, clearer, more profuse and stretchy,
like raw egg white. This fertile-type mucus produces a slippery wet lubricative
sensation at the vulva. The last day of this fertile-type mucus That is, the
vulva feels lubricative) is called the peak of fertility, because it is the most
fertile day of the cycle. You will know it is the last day only in retrospect;
and after this, the important to realize that the peak day is not necessarily
the day of the highest mucus formation; it is simply the last day that the mucus
discharged has fertile characteristics. Ovulation usually occurs with 24 hours
of the peak mucus signal. Therefore, these are the best days to have intercourse
in order to maximize the chances of conception.
Fig 1. Normal cervix
Fig 2. Profuse cervical mucus
Fig 3. The Billing calendar for charting cervical mucus. The
time period marked C is the "fertile period".
Problems with the cervical mucus
In some women, the cervical mucus may prevent the sperm from moving freely
into the uterus. Such a barrier may be because of the following reasons:
- There is not enough of it to allow the sperm to move easily
- The mucus is too thick and sticky
- The mucus is not compatible with the husband's sperm.
Tests on the cervical mucus
Problems with cervical mucus usually cause no symptoms. Tests need to be done
to assess whether the mucus is normal or not.
The doctor examines the cervix and the cervical mucus daily from about the
tenth day of the period. The mouth of the cervix is graded, depending upon how
open it is; and the mucus is graded for its amount; its stretchability ("spinnbarkeit")
; and its ability to fern. For the ferning test, a small drop of mucus is placed
on a glass slide and allowed to dry. It should crystallize, forming branches
which look very like fern leaves. These grades are added to give an Insler mucus
score. Healthy cervical mucus is profuse in volume; very stretchable (upto 10 cm
in length); and ferns easily.
The post coital test (PCT) :- This is one of the oldest tests in
investigating infertility and has been done for well over 100years. Timing the
PCT is critical, and it must be done in the preovulatory period, when the mucus
is profuse and clear. The gynaecologist examines a small sample of the cervical
mucus under a microscope some hours after sexual intercourse. The mucus is
sucked painlessly from the cervical canal during an internal examination. Most
doctors feel that the best time to do this is about 6 to 24 hours after sex, but
this timing is not critical. The test is said to be positive if many normal live
sperm are seen swimming in the mucus sample. The sperm should be swimming in a
fairly straight line and reasonably vigorously. A positive PCT is very
reassuring and implies that :
- The husband is likely to be producing enough normal sperm
- Intercourse results in semen being deposited in the vagina
- The cervical glands are healthy
- Sufficient estrogen is being produced before ovulation, suggesting that
ovulation is normal
- There are no antibodies in the mucus hostile to the sperm
What if the PCT is negative (that is, no sperm are seen in the mucus; or they
are all dead)? Some of the reasons for a negative test are:
- The PCT was not done at the best time. For example, the PCT may have been
done too early or too late in the cycle. Wrong timing is the commonest reason
for a negative test and can even cause repeatedly negative tests.
- There was no ovulation the month of the test - perhaps because of the strain
or stress of making love to order.
- The sperm count was poor. Obviously, men with persistently low sperm counts,
or men with poor motile sperm, may be responsible for a negative PCT.
- There may be an abnormality of the cervix - for example, chronic infection in
the cervix may prevent production of adequate mucus; and some women with a
scarred cervix may not produce enough mucus.Patients who have had surgery on the
cervix ( for example, cervical conisation, in which a cone of cervical tissue is
removed to treat cervical dysplasia) often have this problem.
- The cervix is producing antibodies to the sperm.
- Medications such as clomiphene, tamoxifen, progesterones and danazol - all
drugs used for infertility problems - can interfere with the production of good
Remember that a negative test is meaningful only if it is repeatedly negative
under perfect conditions.
If the mucus is good but the post-coital test is repeatedly bad, an
'in-vitro' mucus penetration test, or sperm invasion test, can be performed.
This is performed simply by putting a drop of freshly removed mucus next to a
drop of freshly ejaculated semen on a microscope slide. The interface between
the two drops is examined for about a quarter of an hour, and it is then
possible to see if the sperm are penetrating the mucus and swimming actively in
it. If this does not occur, then it is likely that there is some form of immune
response between the sperm and the mucus, and further tests should be conducted
to examine this.
Cross-over testing can be performed using the mucus and semen under
examination in various combinations with donor mucus and semen. This will show
if the problem is with the sperm or the mucus.
Another simple test for antisperm antibodies in the mucus is called the sperm
cervical mucus contact test (SCMC for short) where the sperm and mucus are mixed
together. If, under the microscope, the sperm are seen to be shaking in a
characteristic way, this means that there are anti-bodies present.
Cervical problems can be corrected depending upon what the cause is. For
example, if the reason for the poor mucus is:
- lack of ovulation, then ovulation can be induced
- cervical infection, then this can be treated by cauterising or freezing the
abnormal cervical tissue, so that this is destroyed, and is then replaced by
healthy cervical glands
- thick or viscous mucus can occasionally be treated by cough medicines
(expectorants, which contain guaifensin ( Robitussin) in a dose of 1-2 tsp per
day, beginning three to four days prior to when you want to conceive.) Just like
guaifensin helps to thin the thick phlegm if you have a cough, it also helps to
thin the cervical mucus.
- scanty mucus, then mucus production can be enhanced by supplemental
For resistant cervical problems, the easiest solution may be to bypass the
cervix entirely, by injecting the sperm direct into the uterus - intrauterine
Sometimes the problem is one of cervical hostility to the sperm - that is
there are antisperm antibodies in the mucus that are killing the sperm. For this
condition the outlook is now more hopeful:
- Some doctors recommend that the woman avoid contact with sperm for a period
of time. This may cause the antibodies to disappear because their production is
no longer being stimulated by repeated exposure to the antigen. The couple can
have sex, but the husband must wear a condom so that the sperm don't come into
contact with the cervix. This course may be recommended for six months, until
the antibodies have disappeared. For obvious reasons, this treatment is rarely
suggested now a days!
- Some doctors have tried insemination with the husband's semen directly into
the uterus - intrauterine insemination. This means bypassing the cervix and
therefore the site of the antibodies. This treatment has had limited success in
some clinics but there is doubt about its value. This is because if antibodies
are being produced, they may be in the tube and the uterine cavity as well.
- Steroids may be given to prevent production of antibodies. To be effective
they have to be given in high doses and this may cause serious side effects.
However, these treatments are rather experimental and not definitely effective.
- IVF. The presence of antisperm antibodies in the cervix will not interfere
with in vitro fertilisation; and this may be a treatment option for difficult
by Dr. Aniruddha Malpani, MD and Dr. Anjali Malpani, MD.
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