Unexplained
Infertility
from the book How to Have a Baby:
Overcoming Infertility
by Dr. Aniruddha Malpani, MD
and Dr. Anjali Malpani, MD.
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Unexplained
infertility simply means we do not know why the couple is infertile -
it is a confession of medical ignorance. Patients with unexplained infertility
fall into two groups. One is the group who really have no infertility
problem whatsoever, but are just plain "unlucky". The other is the group
which do have a reason for their infertility - but the reason is so subtle,
that with present-day medical technology, we cannot find it.
Infertility
may be said to be 'unexplained' if the woman is ovulating regularly, has
open fallopian tubes with no adhesions or endometriosis ; if the man has
normal sperm production; and the postcoital test is positive. Intercourse
must take place frequently, particularly around the time of ovulation,
and the couple must have been trying to conceive for at least one year.
Using these
criteria, about 10% of all infertile couples have unexplained infertility.
However, the percentage of couples classified as having unexplained infertility
will depend upon the thoroughness of testing; and the sophistication of
medical technology.
The diagnosis
is one of exclusion - that is, one which is made only after all the tests
have been performed and their results found to be normal. This is why,
the frequency of this diagnosis will depend upon how many tests are done
by the clinic - the fewer the tests, the more frequent this diagnosis.
Possible
causes of unexplained infertility
- Tubal
Abnormalities: It is possible that there may be a subtle defect
in the mechanism by which the fimbria "pick up" the egg at ovulation;
or the cilia in the tube may not function properly.
- Abnormal
eggs: It would appear that a very small number of cases of unexplained
infertility are due to the persistent production of abnormal eggs. These
may have a deformed structure or chromosomal abnormalities.
- Trapped
eggs: In some cases it would appear that eggs are produced, and
mature correctly within the follicle which then goes on to become a
corpus luteum without however first bursting to release the egg. The
egg is therefore effectively 'trapped' inside the unbroken corpus luteum
- called a luteinized unruptured follicle (LUF) syndrome.
- Luteal
phase abnormalities: The luteal phase is the part of the cycle that
follows after the egg has been released from the ovary. It may be inadequate
in one way - and this is called a luteal phase defect.
The corpus luteum produces the hormone called progesterone. Progesterone
is essential for preparing the endometrium to receive the fertilized
egg. Several things can go wrong with progesterone production: the rise
in output can be too slow, the level can be too low, or the length of
time over which it is produced can be too short. Another possibility
is a defective endometrium that does not respond properly to the progesterone.
Luteal phase defects can be investigated either by a properly timed
endometrial biopsy; or by monitoring the progesterone output by taking
a number of blood samples on different days after ovulation and measuring
the progesterone level in them.
- Immunological
factors: The immune system can react against the man's sperm, and
kill them, immobilize them or make them stick together.
Women can also develop an immune reaction to the coating of their own
eggs, which can prevent sperm from attaching to them.
- Infections:
Certain infections have been shown to be responsible for some cases
of unexplained infertility. For example, mycoplasma or chlamydia may
be present in numbers that are not enough to show up in a clinical examination,
but which nevertheless cause infertility. This is why some doctors use
empiric therapy with antibiotics.
- Inability
of sperm to penetrate eggs: Some men have a completely normal sperm
count, but their sperm cannot fertilise the egg. The only way to make
this diagnosis is by IVF; if donor sperm can fertilize the eggs; but
the husband's sperm fail to do so, then the diagnosis is confirmed.
- Uterine
factor: Some women have an abnormal endometrium ( uterine lining)
which does not allow the embryo to implant . This is a subtle finding,
which is often missed. It can be diagnosed by doing serial vaginal ultrasound
scans, to assess the thickness and texture of the endometrium. In some
infertile women, the endometrium remains persistently thin. This may
be because of inadequate uterine blood flow, or poor estrogen receptors
in the endometrial cells. This can be a difficult problem to treat,
and therapy is usually empirical ( either low-dose aspirin or high doses
of estrogen).
- Psychological
factors: Studies on infertile groups of men and women have produced
contradictory findings about the importance of psychological factors
in causing infertility. Emotional disturbances undoubtedly appear to
have some significance. This is only reasonable if you realise that
the whole hormonal cycle, with its delicate adjustments, is controlled
from the brain. This is an area which needs further investigation.
Has anything
been missed?
Previous
tests should be carefully reviewed to ensure that the diagnosis is in
fact "unexplained" - and that no test has been omitted or missed. It may
sometimes be necessary to repeat certain investigations. Thus, for example,
if a previous Laparoscopy has been done by a single puncture and been
reported as normal, it may be necessary to repeat the Laparoscopy with
a double puncture, to look for early endometriosis.
How can
unexplained infertility be treated?
Remember,
you still have a fairly good chance of getting pregnant on your own without
needing any treatment at all! If no abnormality is found, your chance
of getting pregnant without treatment within 3 years is about 1 in 3.
Taking treatment helps to increase the chances of your conceiving - and
also makes it likelier that you will get pregnant sooner.
The treatment
of luteal phase defects is as controversial as their diagnosis. They can
be treated by using clomiphene which may help by augmenting the secretion
of FSH and thus improving the quality of the follicle (and therefore the
corpus luteum which develops from it). Direct treatment with progesterone
can also help luteal phase abnormalities. The progesterone can be given
either as injections or vaginal suppositories.
Many patients
are worried that if we are not able to find the cause of the infertility,
we will not be able to treat them. Fortunately, this is not true – today,
our technology for treating infertility is far superior than our technology
for making a diagnosis ! In any case, most infertile couples are not really
interested in a diagnosis of what the problem is – they are much more
interested in finding the solution to their problem - getting a baby !
Today, with assisted reproductive technology, the chance of treatment
being successful is very good. Intrauterine insemination with superovulation
is the simplest approach, and it helps because it increases the chances
of the egg and sperm meeting; but some patients may also need IVF or ZIFT
. IVF can be helpful, because it provides information about the sperm's
fertilizing ability, and also allows the doctor to perform in the lab
what is not happening in the bedroom ( whatever the reason for this )
; ZIFT, on the other hand, has a higher pregnancy rate, and is very useful
in these patients, since they have normal fallopian tubes.
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