If every woman with some displacement
of her uterus had trouble getting pregnant, there would be a significant
drop in the number of babies being born. Almost 20-40% of women who
have never had a baby have some displacement. And over 50-60% of
women who have had a baby have some, too. In other words, the position
of the uterus, when different from what is considered normal, is not pathology
but a variation of the normal.
The classical position of the
pear-shaped, pear-sized uterus is tilted up such that it's top is positioned
behind and above the bladder. The division between the cervix--that
part that sticks through the vaginal wall to be an exit for the baby at
delivery--and the rest of the uterus--called the "corpus," or body of the
uterus--has a pivot. That is, the cervix lies parallel to the long
axis of the woman's body, and the fundus pivots up away from it at an angle,
pointing it up as described above.
When the corpus of the uterus
is pivoted up like this, it is said to be "anteflexed," or angled upward.
If on the other hand it pivots down toward the rectum, it is said to be
"retroflexed." Sometimes it's lying in the same plane
as the cervix, the inside of the cervix and corpus all in one straight
line, with the arrangement between the two referred to as "axial."
I wish explaining this were
easy, but it gets worse.
If the whole uterus, corpus
and cervix, are held loosely in the pelvis such that the whole structure
is relaxed back, it's called "retroverted." So it's possible that
the angle of pivot between the corpus and cervix can still represent a
anteflexed angle, but everything is retroverted. This would tend
to pivot the cervix upward in the vagina against the ceiling, which is
also the floor of the bladder. Such women may feel they have to urinate
because of the pressure against the bladder. On the other hand, a
retroflexed uterus may have pressure falling on the rectum, giving the
sensation of needing to move the bowels.
In the classically normal anteflexed
uterus, there are a number of ligaments that hold it in that position.
The uterosacral ligaments go from the cervix, through the vaginal wall,
and then insert on the sacrum. A growing pregnant uterus will twang
these ligaments giving the famous lower
back pain. The round ligaments originate from the sides of the
uterus, travel away from it toward the pelvic sidewalls where they travel
through the inguinal rings and then spread to insert on the vaginal sidewalls
and inner thighs. A growing pregnant uterus will stretch these as
well, giving the frequent "round ligament" pain
that hurts usually to one side in the inguinal region. The main support
for the uterus are the cardinal ligaments, tough fibrous supports that
line the sides of the lower part of the uterus. The other ligaments
are often lax long before the cardinal ligaments ever weaken.
Of course, once a baby distorts
the anatomy by pulling the ligaments some distance, all bets are off.
But not to worry, because the displacement of the uterus will not contribute
to any infertility. This is due to the relationship between the vagina
and the cervix.
The vagina is called a "potential"
space. (Alright, guys, this isn't because it has a lot of potential.)
What this means is that the vagina is collapsed onto itself unless something
occupies it, be it a baby or the penetration of intercourse. It has
the potential to be a space. Otherwise, it's a collapse of adjacent
tissues. After intercourse, when the semen has been deposited and
the penis withdrawn, the vaginal walls once again fall together, squeezing
the semen like a lubricating layer applied along the adjacent surfaces.
In this enviroment sits the cervix, the opening to the uterus and entrance
for sperm to attempt the long swim toward fertilizing an egg.
What is happening is semen
presented to the cervix by the collapsing vaginal walls. So no matter
whether the uterus is retroflexed, retroverted, prolapsed, etc., infertility
is not a result.
About the only problem a retroflexed
uterus may present in pregnancy is at about 12 weeks, when the uterus is
no longer small enough to fit in the pelvis. At this point is size
mandates it to be an abdominal organ, and if it's jammed into the sacrum
(top of the tail bone) it may hurt in that cramped position until it pops
up into the abdomen for the rest of the pregnancy. This pain is harmless,
thankfully.
Sometimes a displaced uterus
can cause pain: lower back pain, pain with
intercourse, a feeling of heaviness by the end of the day, pelvic aching
after exercise, or painful periods.
(A sharply flexed corpus can provide quite an impediment to the exit of
menstrual clots from the uterus. This tends to cause cramping as the uterus
tries its hardest to expel the menstrual flow.)
Non-steroidal anti-inflammatory
drugs (NSAIDS) are effective in treating this type of pain for the most
part.When even they can't ameliorate the pain, women are faced with
the dilemma of either living with the anatomy that pains them or having
a hysterectomy. A middle ground therapy involves
an operation called a "uterine suspension." One would think this
is a good solution for women who aren't ready to consider hysterectomy.
Unfortunately this operation, which involves tightening or suspending the
round ligaments, usually fails because of using the weakest ligaments.
Displacement of the uterus
is usually an incidental finding on physical exam. Sometimes it can
be in association with weakening of other pelvic supports, leading to rectal
pain or urinary incontinence, but in most women
is without any symptoms and requires no intervention.
And in answer to your question,
it won't interfere with fertility.
