Frequently asked questions about Malposition of Uterus
Mal-position of the Uterus
Introduction
Intermittent myometrial contractions and changes in uterine position are normal during pregnancy. Infrequently, various obstetric complications result from uterine malpositioning (retroversion or incarceration), inversion, and, in rare cases, prolapse, torsion, or herniation. Special devices and many surgical techniques were developed to either reposition the uterus or to hold it in its presumed correct location. These operations and manipulations were believed to be necessary for the maintenance or restoration of normal functioning.
In modern time, surgery for the correction of uterine retroversion in the absence of evidence of endometriosis or other specific pathologic conditions has fallen into disrepute.
Retroversion from any cause becomes an issue of clinical importance if it progresses to uterine incarceration once a pregnancy is established. Fixation of the uterus by adhesions is also a risk factor for the rare complication of uterine torsion.
Uterine Retroversion or Incarceration
Frequency
During early pregnancy, uterine retroversion is a normal positional variant. Typically, first-trimester retroversion is intermittently present 10-20% of the time. If retroversion persists into the mid trimester, uterine incarceration is possible, but the likelihood of this complication is low.
Pathophysiology
Normal pelvic anatomy permits the fundus of the uterus to move relatively freely in the sagittal, vertical, oblique, and anteroposterior planes. In retroversion, the uterus is tipped posteriorly and may be fixed in this position by the presence of adhesions. Cases of marked retroversion with the uterine fundus positioned below the sacral promontory in the hollow of the pelvis lead to incarceration as the uterus enlarges during pregnancy. As the uterus becomes bigger, the fundus progressively moves posteriorly as it cannot escape from the cul de sac. As this occurs, the cervix is driven underneath and then behind the pubic symphysis. At some critical juncture of uterine size, tissue laxity, and other unknown factors, the uterus becomes entrapped. At this point, the fundus cannot easily exit the hollow of the sacrum or it is incapable of spontaneously rotating anteriorly past the sacral promontory.
Entrapment usually occurs after the 12th week of gestation. However, it may occur earlier if special conditions such as a multiple gestation or a müllerian anomaly exist, or if a strategically located leiomyoma or adnexal tumor is present.
In cases, a variety of conditions are possible:
- Adhesions due to previous surgery
- Adhesions due to endometriosis
- Adhesions due to previous pelvic inflammatory disease
- Müllerian abnormalities with a posterior uterine horn or a rudimentary horn
- Adnexal tumor or a fundal or posterior leiomyoma
As gestation advances, the incarceration worsens. Because the enlarging uterus cannot rotate anteriorly, it is wedged progressively firmly into the hollow of sacrum while the cervix exerts increasing pressure toward the urethra and/or bladder. Normal voiding eventually becomes difficult or impossible as progressive upward cervical pressure restricts normal funneling of the bladder outlet and obliterates the posterior uterovesical angle.
Clinical Presentation
Recurrence is possible. Thus, women with a history of symptomatic incarceration should be evaluated frequently in the late first trimester and early second trimester to ensure that the uterus does not become fully incarcerated if it remains retroverted.
When incarceration occurs, the acute symptoms mimic those of more common obstetric conditions. Yet, in most instances, the correct diagnosis is readily established by reviewing the clinical history and performing a pelvic examination. Conducting a real-time ultrasonic examination is confirmatory.
Uterine repositioning is usually easy and successful if the diagnosis is made early.
Common clinical symptoms include the following:
- Vaginal bleeding (threatened spontaneous abortion)
- Pain
- Uterine contractions or cramping
- Paradoxical urinary symptoms (e.g., incontinence, frequency, and, eventually, retention)
- Bowel dysfunction (e.g., tenesmus, rectal pressure, constipation)
Diagnosis
The diagnosis of incarceration is established by performing a pelvic examination and pelvic sonography and by considering these data in combination with the characteristic clinical history.
In cases of retroversion with incarceration, clinical examination usually yields the following striking findings:
- A soft, smooth, non tender mass filling the cul-de-sac
- Acute anterior angulation of the vagina
- A cervix abutting firmly against or positioned well behind the pubic symphysis
- An inability to palpate the uterus during abdominal examination or a uterine fundus too small for the known gestational age
Treatment
Possible therapies for retroversion with incarceration include the following:
- Manual uterine replacement: manipulation of the uterus into its usual anatomic position, with or without tocolysis and/or anesthesia
- Bladder decompression by means of intermittent or indwelling catheter drainage
- Colonoscopic manipulation of the uterine fundus with the patient under anesthesia
- Patient positioning (e.g., intermittent knee-chest or all-fours positioning, sleeping prone)
- Application of specialized and rarely attempted techniques of replacement (e.g., use of a mercury-filled Voorhees bag in the vagina, amniocentesis with manipulations or surgical exploration and replacement)
Bladder decompression and patient positioning
The best initial treatment for symptomatic mid trimester incarceration of a normal uterus is a trial of bladder decompression combined with a program of patient positioning. Such management relieves most cases.
Manipulation of the uterus
Before the procedure begins, the woman is instructed to void, or, if a Foley catheter was placed, it is fully drained. An attendant is present to support and encourage the patient and to help prevent a fall. In the replacement procedure, a speculum is passed and the anterior lip of the cervix is grasped by using a long Allis clamp or another atraumatic clamp.
The patient is then placed in the knee-chest or all-fours position. The surgeon inserts a finger into the vagina or rectum and applies pressure to the incarcerated fundus while simultaneously applying gentle but constant traction to the cervix. With this combined technique, the uterus should slowly rotate into its normal position. In theory, passing the fundus to either side of the sacral promontory, where more room is available, is probably best. Use of real-time sonographic guidance during manipulation procedures is prudent. Successful replacement is verified by means of palpation and real-time ultrasonography.
Postprocedural care
After any procedures to attempt uterine replacement, administration of Rh immunoglobulin is indicated in Rh-negative patients who are not isoimmunized.
In rare cases of chronic uterine retroversion, ballooning out of the uterine wall (sacculation) may permit the uterus to expand abdominally. If this occurs, the pregnancy may progress even into the third trimester. In such instances, the correct diagnosis is established only when dystocia in labor ensues or when abdominal and/or pelvic examination reveals markedly unusual findings that lead to an MRI study. In the rare case that reaches the third trimester, the uterine malpositioning is fixed and cesarean delivery is required. In the mid trimester, spontaneous abortion may occur because of incarceration alone, or it may follow manual uterine replacement. The risk of such loss is believed to be low.
Etiology of retroversion
In non pregnant women, if retroversion alone is the cause of symptoms, these are usually minimal. Pelvic pain and similar symptoms are principally due to coincidental pathology. Evidence to show that isolated retroversion is responsible for abortion or infertility is lacking. When these conditions are encountered, another etiology must be sought.
Multiple gestations
Multiple gestations, which now often occur in association with assisted reproductive technologies, are special cases. In this setting, the uterus can become incarcerated earlier in gestation than when only a single fetus is present. This change is presumably due simply to the increased size of the uterus. Therefore, if characteristic symptoms occur in women with known multiple gestations—even when the pregnancy has not reached 12 weeks of gestation—retroversion or incarceration should remain in the differential diagnosis.
Persistent retroversion
In a few cases, the uterus remains retroverted and cannot be repositioned despite the administration of tocolysis and the use of regional anesthesia. The best management strategy in this setting is moot.
Counseling
Patients should be informed that both symptomatic incarceration and efforts for its relief carry some risk of pregnancy loss.
Ultrasonography
Because of the general uncertainties, a real-time sonographic examination should precede any intervention. This imaging study is done to reassure both the patient and practitioner, to verify the original diagnosis, to confirm that an anatomically normal and living fetus is present, and to verify that a mass or tumor is not the cause of the incarceration. The study is repeated after repositioning to confirm success of the procedure to verify the presence of an active fetus and normal amniotic fluid.
Other Syndromes of Pelvic Pain/Retroversion
Allen-Masters syndrome: The pelvic congestion syndrome
In non pregnant patients, the evaluation of chronic pelvic pain that accompanies uterine retroversion includes a consideration of 2 indistinct and somewhat suspect syndrome complexes: pelvic congestion syndrome (PCS) and Allen-Masters syndrome (AMS).
Pelvic congestion (Taylor) syndrome
Another possible diagnosis is PCS, or Taylor syndrome. This condition is characterized by menometrorrhagia and symptoms of continuous pelvic pain. On examination, the uterus is variably enlarged and soft, and some degree of tenderness is present. Uterine retroversion is again a common but not invariable finding. The cervix may be patulous or cyanotic. Among other treatment possibilities, both hysterectomy and vascular embolization have been used to manage PCS. The symptoms of this condition are nonspecific and poorly defined. Both this and the AMS are suspect diagnostic entities. In unusual or difficult cases, MRI can safely complement ultrasonography to help establish the correct diagnosis.
Uterine Torsion
Frequency
Uterine torsion is a rare condition in humans, and the existing papers are restricted to scattered case reports. Most cases of torsion are reported in the veterinary literature.
Pathophysiology
Dextrorotation is the most common finding. This is the normal orientation of the myometrial fibers. In rare situations, the torsion is of a sufficient degree to interfere with uterine circulation. This results in acute maternal symptoms or threatens fetal survival by directly restricting blood flow or by inducing abruption placentae.
Entities reportedly associated with torsion include the following:
- External cephalic version procedures
- Interstitial pregnancy
- Abnormal fetal presentation (e.g., a transverse lie)
- Pelvic adhesions
- Distortion in uterine shape due to uterine leiomyomas
- Müllerian anomalies
- Large ovarian neoplasms that distort the shape or position of the uterus
- Congenital weakness at the junction of the cervix and uterine corpus
- Sudden maternal movements, as may occur during automobile accidents or, most rarely, during normal activity
- Long or rigid cervix or structural weakness at the junction of the cervix and the uterine corpus (possibly after a prior cesarean delivery)
- Abnormal pelvic architecture
- Hydramnios
- Multiple gestation
- Hyperactive fetus
- Unknown and/or idiopathic factors
Clinical Presentation
If the torsion occurs at term, obstructed labor is possible, or an acutely abnormal electronic fetal monitoring tracing may develop.
Diagnosis
The clinical challenge of uterine torsion lies in its elusive diagnosis. However, MRI has recently been used to make the diagnosis prior to exploratory surgery.
Uterine torsion is a rare obstetric complication. Nonetheless, because of its associated risks, torsion should be included in the differential diagnosis when severe but nonspecific abdominal pain occurs during pregnancy.
Treatment
In general, treatment of torsion depends on the gestational age. When torsion is discovered during exploratory surgery before the period of presumed fetal survival (i.e., before 23-24 wk), promptly returning the uterus to the normal position is the principal therapy.
When the fetus is beyond the 34th week at the time of diagnosis, the best approach is cesarean delivery at the time of the original laparotomy procedure.
Timing of diagnosis and maternal/fetal risk
Because potentially serious sequelae are possible, establishing the correct diagnosis of uterine torsion early, before complications ensue, is the challenge for clinicians.
Uterine Herniation
Frequency
Herniation of the uterus through an abdominal wall defect (also known as incisional hernia or umbilical hernia of pregnancy) is, at best, an uncommon condition.
Presentation
The clinical presentation is striking. Usually during the mid-trimester, the uterus prolapses into the hernia sac via anterior anteflexion. The protrusion of the abdomen is remarkable. Necrosis or ulceration of overlying skin is also possible.
Pathophysiology
A number of potentially serious complications including spontaneous abortion, strangulation/incarceration, abruptio placentae, uterine rupture, and intrauterine death have been associated with these hernias. The constant pressure of the uterus against the hernia sac may also result in ulceration of the overlying skin.
Diagnosis
The diagnosis is confirmed by a combination of simple palpation and real time ultrasound scanning.
Treatment
Both incarceration and serious complications are possible with this disorder.
Herniorrhaphy has been performed during pregnancy but definitive repair of the abdominal wall defect is normally conducted only following delivery. The abdominal wall is often so attenuated that extensive repair with a permanent mesh is required.
Uterine Inversion
Frequency
Postpartum partial or complete uterine inversion is an uncommon but potentially life-threatening obstetric complication.
Pathophysiology
Terminology for the severity of an inversion is based on 2 clinical features: (1) the extent of prolapse in relation to the cervix and (2) how far down the birth canal the resultant mass extends.
Associations with uterine inversion include the following:
- Idiopathic factors
- Precipitate labor
- Fetal macrosomia
- Excessive cord traction or a short umbilical cord
- Intrapartum fundal pressure (Credé maneuver)
- Myometrial weakness or uterine sacculation
- Trials of vaginal birth after cesarean delivery (VBAC)
- Placenta accreta, increta, or percreta
- Fundal implantation of the placenta
- Chronic endometritis
- Acute tocolysis with nitroglycerin or other potent tocolytic drugs
- Cesarean delivery
Clinical Presentation
Early-onset postpartum hemorrhage and the sudden appearance of a vaginal mass followed by various degrees of maternal cardiovascular collapse are the classical symptoms. Postpartum hemorrhage is usually the most striking symptom and initially commands the clinician's attention.
Due to the potential complexities of presentation, prompt ultrasonographic scanning is the most helpful technique in uncertain cases. If accompanying hemorrhage or shock is sufficiently alarming to prompt immediate surgical exploration, the correct diagnosis may be established only at laparotomy.
Chronic uterine inversion:
This diagnosis is difficult to establish on clinical grounds alone. Here again, real-time ultrasonography is especially helpful. Most of these late cases will require surgical procedures for replacement.
Diagnosis
The following entities are included in the differential diagnosis of uterine inversion:
- Occult laceration of the genital tract
- Prolapse of a uterine tumor or a large cervical polyp
- Uterine rupture
- Foreign body in the vagina
- Passage of previously unsuspected secundines or a succenturiate lobe
- Gestational trophoblastic disease
- Severe uterine atony
- Unanticipated delivery of a second twin
Treatment
Rapid diagnosis and aggressive management of uterine inversion minimizes the principal risks of acute inversion, which are hemorrhage, and cardiovascular collapse or shock. Proper treatment tests the ability of the institution to mount a prompt team-based response to this normally unanticipated, but potentially serious, obstetric complication. After uterine inversion occurs, prompt treatment of hemorrhage and shock is vital in limiting maternal morbidity and the risk of mortality.
Manage shock
Summon nursing assistance and another surgeon.
Begin fluid resuscitation with 2 large-bore intravenous lines. Promptly administer 1 L or more of an isotonic salt solution (Ringer's lactate).
Submit specimens to the laboratory to prepare for possible transfusion of blood or blood products. Also send samples to determine baseline values of the following:
- Hematocrit
- Hemoglobin concentration
- Coagulation factors (e.g., prothrombin time, activated partial thromboplastin and time, level of fibrinogen)
Insert a Foley catheter.
Immediately summon an anesthesiologist.
Treat aggressively
Administer oxygen.
Order the appropriate surgical equipment, and instruct assistants to prepare the operating room for possible laparotomy.
Once in the operating room, administer tocolytics to promote uterine relaxation. These drugs may include one of following:
- Terbutaline 0.100-0.250 mg given slowly intravenously
- Nitroglycerin 0.250-0.500 mg given intravenously over 1-2 minutes (preferred)
- Magnesium sulfate 4-6 g administered intravenously over 20 minutes (less effective and not recommended as initial treatment)
Attempt prompt replacement of the uterus:
- Begin with a trial of manual replacement per vagina. Conducted with adequate uterine relaxation, this maneuver is highly likely to be successful.
- If manual replacement fails, promptly perform laparotomy to achieve surgical replacement unless the clinician is trained in one of the vaginal surgical approaches. During laparotomy, general anesthesia with a uterine-relaxing agent is best, especially if a parenteral tocolytic was not previously given or if it appears to have failed.
Repair
Manually replace uterus.
Suture lacerations of the birth canal and any surgical incisions in the cervix or vagina,
Perform uterine massage after replacement of the uterus.
Administer uterotonics.
Closely monitor the patient for several hours after the uterus is replaced to detect spontaneous reinversion.
Surgical techniques
If 2 or more attempts at manual replacement are unsuccessful despite adequate tocolysis and analgesia, a surgical procedure is indicated. An abdominal approach for uterine replacement is favored.
Inversion in non pregnant women
Inversion is rarely observed in non pregnant women. The characteristic finding in these most unusual patients is a pedunculated subserosal leiomyoma or other neoplasm at or adjacent to the uterine fundus. The usual culprits are endometrial polyps and pedunculated leiomyomata.
Consultations
In the rare case when pregnancy-related inversion is long standing or when manual replacement is unsuccessful and surgical replacement is required, consultation with an experienced clinician is advised. During surgery, the presence of 2 operators speeds above-and-below procedures and reduces the risk of iatrogenic injury to the uterus or adjacent structures
Uterine Prolapse
Frequency
Uterine prolapse during gestation is an infrequent clinical problem, though moderate degrees of descensus are common before pregnancy, especially in multiparas. If not severe, pregnancy-associated prolapse often partially or completely resolves in the mid trimester as the fundus grows and the uterus becomes an abdominal organ, drawing the cervix upward. In such cases, symptomatic prolapse usually recurs in the third trimester, or, on occasion, it is first observed at this time.
Pathophysiology
The female pelvic viscera are best considered to be suspended from above and supported from below. To maintain the pelvic organs in their proper position, their suspensory and support structures must remain intact and interact. This joint function depends on the integrity of the muscular, fascial, and neurologic components of these various tissues. Substantial injury to one or more of these systems can result in a loss of support and result in a degree of prolapse that may prove permanent.
Clinical Presentation
Signs and symptoms associated with uterine prolapse may include the following:
- Preterm labor
- Pelvic pressure or discomfort
- Preterm membrane rupture
- Lower back pain
- Cervicitis, vaginitis, vaginal discharge
- Urinary tract infection
- Vaginal or perineal mass
- Paradoxical urinary tract symptoms (e.g., acute retention, incontinence)
- Bleeding due to mucosal ulcerations or cervicitis
- Constipation
Diagnosis
Establishing the diagnosis is not a challenge. On examination, the clinician observes unusual cervical descent, accompanied by variable protrusion of the anterior and posterior vaginal walls.
Uterine distortion due to tumors such as large leiomyomas or other masses, prolapse of a cervical or endocervical tumor, or a müllerian anomaly must be considered in the differential diagnosis.
Results from physical examination and ultrasonographic study should promptly establish the correct diagnosis.
Treatment
Aspects of treatment are as follows:
- Restrict activity.
- Aggressively treat cervicitis or soft tissue erosions of the birth canal.
- Conduct a trial of a pessary.
- Treat associated urinary tract infections.
- Determine the fetal fibronectin value.
- Administer corticosteroids to enhance fetal pulmonic maturity.
- Serially assess fetal growth, and sonographically verify normality of fetal anatomy.
- If appropriate, conduct ultrasound.
Serious complications
A number of serious complications are there in association with prolapse during pregnancy.
Among non pregnant women, hysterectomy with vault suspension is usually required to definitively repair advanced degrees of prolapse. The necessary procedure depends on the severity of the problem and on the individual's pelvic anatomy.
