Uterine Position and Infertility

December 14, 2007

Uterine prolapse (descensus), retroverted uterus, etc., and pain

Uterine Prolapse

Q & A: I have a retroverted, prolapsed uterus.  Will this make it harder for me to get pregnant?  What are other problems associated with this?

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.

Dealing With Pain

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.

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