from
the book How to Have a Baby: Overcoming Infertility
by Dr. Aniruddha Malpani, MD and Dr. Anjali Malpani,
MD.
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What
are the new techniques for studying the role of the
endometrium in infertility ?
Endometrial or uterine polyps are soft, fingerlike growths
which develop in the lining of the uterus (the endometrium).
They develop because of excessive multiplication of
the endometrial cells, and are hormonally dependent
, so that they increase in size depending upon the estrogen
level. They can usually be detected on an ultrasound
scan if this is done mid-cycle, when estrogen levels
are maximal, but are easily missed if the scan is not
done at the right time of the menstrual cycle. Polyps
are an uncommon but important cause of infertility,
because they can easily be removed during hysteroscopic
surgery.
Fig 1. Uterine polyp as seen during hysteroscopy
Fig 2. Uterine polyp seen during ultrasound scan after
infusion of saline which outlines the polyp in the cavity
While the commonest problem found in the uterus is a
fibroid (myoma or leiomyoma), this is rarely a cause
of infertility, and is usually an incidental finding
of little importance. Fibroids are common benign smooth
muscle tumors which arise in the wall of the uterus,
and may be single or multiple. About 25% of all women
over the age of 35 have fibroids.
Most fibroids develop in the wall of
the uterus (intramural ) or protrude outside of the
uterine wall (subserous fibroids), and these can usually
be left alone, since they do not hinder fertility, and
neither do they cause problems during the pregnancy.
In fact, unnecessary surgery to remove the fibroid often
causes more harm than good. This surgery often creates
adhesions, which causes the tubes to get blocked.
However, if the fibroids are very large,
they may need surgical removal, and this procedure is
called a myomectomy. Some doctors give an injection
of a GnRH analog prior to surgery in order to shrink
the fibroid and make surgery technically easier. When
performed by an expert, it is a safe and effective procedure
which can be accomplished with minimal blood loss. However,
sometimes because of uncontrollable bleeding the surgeon
may be forced to remove the entire uterus (a procedure
called a hysterectomy), and this is obviously a disaster
for the infertile woman!
The standard technique for removing
a fibroid is through open surgery (laparotomy). It is
now also possible to remove fibroids through the laparoscope,
but laparoscopic myomectomy does not allow for optimal
reconstruction of the uterus. Submucous fibroids are
an important cause of infertility, because they interfere
with implantation of the embryo, by acting as a foreign
body. These are best removed by an operative hysteroscopy.
While surgery can remove the fibroid, it can recur again,
and most doctors advise the patient to try to conceive
as soon as possible after surgery.
Fig 2. Schematic showing a submucous fibroid; and a
subserous fibroid compressing the right fallopian tube
Fibroids may grow larger during the
pregnancy, but usually pregnancy and delivery are uneventful.
In rare cases, after a myomectomy, uterine rupture may
occur during pregnancy or delivery, and this complication
may result in severe blood loss, fetal loss and even
maternal death.
Because of the potential for catastrophic
results, it is recommended that women have cesarean
deliveries in the following circumstances: 1) when the
myomectomy involved full-thickness incision of the uterine
wall or multiple deep uterine incisions or 2) when myomectomy
was complicated by infection which may have weakened
the uterine wall or 3) when there is doubt regarding
the adequacy or extent of the uterine repair.
The uterus was often a neglected organ
in the infertility workup, partly because we did not
have the tools to study it properly. Hysteroscopy, hysterosalpingography
and vaginal ultrasound are all complementary procedures
for evaluating the uterine cavity in the infertile woman.
The HSG is good for looking for polyps, adhesions and
septa which appear as "filling defects" on the X-ray.
However, careful radiologic technique is a must. Vaginal
ultrasound is excellent for detecting submucosal fibroids
or polyps, which can be missed on hysteroscopy and HSG.
Of course, the major advantage of hysteroscopy is it
offers the chance of treating the problem as well!
What
are the new techniques for studying the role of the
endometrium in infertility ?
We are now also developing newer techniques
to study the uterus. One of our major areas of ignorance
today is the complex process of embryo implantation.
It is obvious that the endometrium has a key role to
play in this process, in which the embryo has to appose
and attach itself to the maternal endometrium and invade
into it. At present, the tools we have to study endometrial
function and receptivity are very crude. They include
primarily transvaginal ultrasound, to assess the endometrial
thickness and texture, but this provides very limited
and indirect evidence of endometrial functions. Colour
Doppler ultrasound has also been used to assess endometrial
blood flow ( perfusion), but its utility is limited.
Since embryo-endometrium interaction
is a biochemical process, a lot of study has been done
on the role of the molecules involved in this process.
Recent research has shown that the normal endometrium
contains various cell adhesion proteins called integrins,
which allow the embryo to interact with it. Studies
have shown that the endometrium of some infertile women
is deficient in some of these integrins, and this deficiency
may be responsible for failure of the embryo to implant
successfully. Thus, testing the endometrium for beta
integrin can be a useful marker for uterine receptivity.
This test involves doing an endometrial biopsy at a
specific point in the menstrual cycle, and evaluating
this with special staining techniques, but is only available
on a research basis so far.
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